Testing CI

Fix Mobile View for MUI data-grid (CARD 108)

.github/CODEOWNERS

@@ -36,5 +36,5 @@ Cargo.* @durch @futurechimp @jstuczyn @neacsu
 
 # Explorer and wallet should probably get looked by the product team
 /explorer/ @nymtech/product 
-/tauri-wallet/ @nymtech/product 
+/nym-wallet/ @nymtech/product 
 /wallet-web/ @nymtech/product

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,32 @@
+---
+name: Feature request
+about: Suggest an enhancement to the product
+title: "[Feature Request]"
+labels: enhancement
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is...
+
+**Is your request a feature not related to an existing problem? A new feature.**
+For example. 
+- Given I am using the nym wallet
+- When I transfer nym tokens across the network
+- Then I want to have an url link in the wallet which navigates outside the application to the nym-explorer
+
+**Where does the feature fit in the Nym real estate?**
+- Application / UI 
+
+**What is this solving?**
+How will this improve the product...
+
+**Is this an update to packages or libraries?**
+If so, please list them. If not, please ignore this section.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.

.github/ISSUE_TEMPLATE/report.md

@@ -0,0 +1,43 @@
+---
+name: Report
+about: To help identify and reproduce issues
+title: "[Issue]"
+labels: bug, bug-needs-triage, qa
+assignees: tommyv1987
+
+---
+
+**Describe the issue**
+A clear and concise description of what the issue is...
+
+**Expected behaviour**
+A clear and concise description of what you expected to happen...
+
+**Stack Traces**
+If there are stack traces or logs, please provide them here...
+
+**Steps to Reproduce**
+Steps to reproduce the behaviour, if you're familiar with BDD syntax, please write it in this style:
+- Given I was doing X
+- And I installed Y
+- When I actioned Y
+- Then I expect Z
+
+*An example:*
+- Given I was setting up a mix-node following the instructions in the docs
+- And I successfully bonded my node via the the wallet
+- When I went to start my mixnode
+- Then I was presented with an error
+
+**Screenshots**
+If applicable, add screenshots to help explain your problem...
+
+**Which area of Nym were you using?**
+ - UI: [e.g. Websites - network-explorer, nym-website]
+ - Application: [e.g Gateway, Client, Wallet]
+ - OS: [e.g. Ubuntu 20.x, MacOs Big Sur, Windows 10]
+ - Browser: [e.g Chrome (if applicable)]
+ - Version: [e.g. nym binary(0.11.0), browser(94.0)]
+
+**Additional context**
+Please provide any other information

.github/workflows/build.yml

@@ -1,16 +1,32 @@
 name: Continuous integration
 
-on: [push, pull_request]
+on:
+  push:
+    paths-ignore:
+      - 'explorer/**'
+  pull_request:
+    paths-ignore:
+      - 'explorer/**'
 
 jobs:
+  matrix_prep:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      # creates the matrix strategy from build_matrix_includes.json
+      - uses: actions/checkout@v2
+      - id: set-matrix
+        uses: JoshuaTheMiller/conditional-build-matrix@main
+        with:
+          inputFile: '.github/workflows/build_matrix_includes.json'
+          filter: '[?runOnEvent==`${{ github.event_name }}` || runOnEvent==`always`]'
   build:
+    needs: matrix_prep
+    strategy:
+      matrix: ${{fromJson(needs.matrix_prep.outputs.matrix)}}
     runs-on: ${{ matrix.os }}
     continue-on-error: ${{ matrix.rust == 'nightly' || matrix.rust == 'beta' || matrix.os == 'windows-latest' }}
-    strategy:
-      matrix:
-        rust: [stable, beta, nightly]
-        os: [ubuntu-latest, macos-latest, windows-latest]
-
     steps:
       - name: Install Dependencies (Linux)
         run: sudo apt-get update && sudo apt-get install libwebkit2gtk-4.0-dev build-essential curl wget libssl-dev libgtk-3-dev squashfs-tools
@@ -45,6 +61,13 @@ jobs:
           command: fmt
           args: --all -- --check
 
+      - uses: actions-rs/clippy-check@v1
+        name: Clippy checks
+#        if: matrix.os == 'ubuntu-latest' && matrix.rust == 'stable'
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: --all-features
+
       - name: Run clippy
         uses: actions-rs/cargo@v1
         if: ${{ matrix.rust != 'nightly' }}
@@ -59,78 +82,21 @@ jobs:
         with:
           command: clean
 
-      # BUILD
-      - name: Build gateway with coconut feature
+      - name: Build all binaries with coconut enabled
         uses: actions-rs/cargo@v1
         with:
           command: build
-          args: --bin nym-gateway --features=coconut
+          args: --all --features=coconut
 
-      - name: Build native client with coconut feature
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --bin nym-client --features=coconut
-
-      - name: Build socks5 client with coconut feature
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --bin nym-socks5-client --features=coconut
-
-      - name: Build validator-api with coconut feature
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --bin nym-validator-api --features=coconut
-
-# TEST
-      - name: Test gateway with coconut feature
+      - name: Run all tests with coconut enabled
         uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --bin nym-gateway --features=coconut
+          args: --all --features=coconut
 
-      - name: Test native client with coconut feature
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --bin nym-client --features=coconut
-
-      - name: Test socks5 client with coconut feature
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --bin nym-socks5-client --features=coconut
-
-      - name: Test validator-api with coconut feature
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --bin nym-validator-api --features=coconut
-
-# CLIPPY
-
-      - name: Run clippy on gateway with coconut feature
+      - name: Run clippy with coconut enabled
         uses: actions-rs/cargo@v1
+        if: ${{ matrix.rust != 'nightly' }}
         with:
           command: clippy
-          args: --bin nym-gateway --features=coconut -- -D warnings
-
-      - name: Run clippy on native client with coconut feature
-        uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: --bin nym-client --features=coconut -- -D warnings
-
-      - name: Run clippy on socks5 client with coconut feature
-        uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: --bin nym-socks5-client --features=coconut -- -D warnings
-
-      - name: Run clippy on validator-api with coconut feature
-        uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: --bin nym-validator-api --features=coconut -- -D warnings
+          args: --features=coconut -- -D warnings

.github/workflows/build_matrix_includes.json

@@ -0,0 +1,50 @@
+[
+  {
+    "os":"ubuntu-latest",
+    "rust":"stable",
+    "runOnEvent":"always"
+  },
+
+  {
+    "os":"windows-latest",
+    "rust":"stable",
+    "runOnEvent":"pull_request"
+  },
+  {
+    "os":"macos-latest",
+    "rust":"stable",
+    "runOnEvent":"pull_request"
+  },
+
+  {
+    "os":"ubuntu-latest",
+    "rust":"beta",
+    "runOnEvent":"pull_request"
+  },
+  {
+    "os":"windows-latest",
+    "rust":"beta",
+    "runOnEvent":"pull_request"
+  },
+  {
+    "os":"macos-latest",
+    "rust":"beta",
+    "runOnEvent":"pull_request"
+  },
+
+  {
+    "os":"ubuntu-latest",
+    "rust":"nightly",
+    "runOnEvent":"pull_request"
+  },
+  {
+    "os":"windows-latest",
+    "rust":"nightly",
+    "runOnEvent":"pull_request"
+  },
+  {
+    "os":"macos-latest",
+    "rust":"nightly",
+    "runOnEvent":"pull_request"
+  }
+]

.github/workflows/clippy_check.yml

@@ -1,14 +0,0 @@
-name: Clippy check
-
-on: push
-
-jobs:
-  clippy_check:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v1
-      - run: rustup component add clippy
-      - uses: actions-rs/clippy-check@v1
-        with:
-          token: ${{ secrets.GITHUB_TOKEN }}
-          args: --all-features 

.github/workflows/contract_matrix_includes.json

@@ -0,0 +1,14 @@
+[
+  {
+    "rust":"stable",
+    "runOnEvent":"always"
+  },
+  {
+    "rust":"beta",
+    "runOnEvent":"pull_request"
+  },
+  {
+    "rust":"nightly",
+    "runOnEvent":"pull_request"
+  }
+]

.github/workflows/erc20_bridge_contract.yml

@@ -0,0 +1,58 @@
+name: ERC20 Bridge Contract
+
+on: [ push, pull_request ]
+
+jobs:
+  matrix_prep:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      # creates the matrix strategy from build_matrix_includes.json
+      - uses: actions/checkout@v2
+      - id: set-matrix
+        uses: JoshuaTheMiller/conditional-build-matrix@main
+        with:
+          inputFile: '.github/workflows/contract_matrix_includes.json'
+          filter: '[?runOnEvent==`${{ github.event_name }}` || runOnEvent==`always`]'
+  erc20-bridge-contract:
+    needs: matrix_prep
+    strategy:
+      matrix: ${{fromJson(needs.matrix_prep.outputs.matrix)}}
+    # since it's going to be compiled into wasm, there's absolutely
+    # no point in running CI on different OS-es
+    runs-on: ubuntu-latest
+    continue-on-error: ${{ matrix.rust == 'nightly' }}
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.rust }}
+          target: wasm32-unknown-unknown
+          override: true
+          components: rustfmt, clippy
+
+      - uses: actions-rs/cargo@v1
+        env:
+          RUSTFLAGS: '-C link-arg=-s'
+        with:
+          command: build
+          args: --manifest-path contracts/erc20-bridge/Cargo.toml --target wasm32-unknown-unknown
+
+      - uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --manifest-path contracts/erc20-bridge/Cargo.toml
+
+      - uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: --manifest-path contracts/erc20-bridge/Cargo.toml -- --check
+
+      - uses: actions-rs/cargo@v1
+        if: ${{ matrix.rust != 'nightly' }}
+        with:
+          command: clippy
+          args: --manifest-path contracts/erc20-bridge/Cargo.toml -- -D warnings

.github/workflows/mixnet_contract.yml

@@ -1,16 +1,34 @@
 name: Mixnet Contract
 
-on: [push, pull_request]
+on:
+  push:
+    paths-ignore:
+      - 'explorer/**'
+  pull_request:
+    paths-ignore:
+      - 'explorer/**'
 
 jobs:
+  matrix_prep:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      # creates the matrix strategy from build_matrix_includes.json
+      - uses: actions/checkout@v2
+      - id: set-matrix
+        uses: JoshuaTheMiller/conditional-build-matrix@main
+        with:
+          inputFile: '.github/workflows/contract_matrix_includes.json'
+          filter: '[?runOnEvent==`${{ github.event_name }}` || runOnEvent==`always`]'
   mixnet-contract:
     # since it's going to be compiled into wasm, there's absolutely
     # no point in running CI on different OS-es
     runs-on: ubuntu-latest
     continue-on-error: ${{ matrix.rust == 'nightly' }}
+    needs: matrix_prep
     strategy:
-      matrix:
-        rust: [ stable, beta, nightly ]
+      matrix: ${{fromJson(needs.matrix_prep.outputs.matrix)}}
     steps:
       - uses: actions/checkout@v2
 
@@ -23,6 +41,8 @@ jobs:
           components: rustfmt, clippy
 
       - uses: actions-rs/cargo@v1
+        env:
+          RUSTFLAGS: '-C link-arg=-s'
         with:
           command: build
           args: --manifest-path contracts/mixnet/Cargo.toml --target wasm32-unknown-unknown

.github/workflows/network-explorer-lint.yml

@@ -0,0 +1,23 @@
+name: Linting for Network Explorer (eslint/prettier)
+
+on:
+  pull_request:
+    paths:
+      - 'explorer/**'
+
+defaults:
+  run:
+    working-directory: explorer
+
+jobs:
+  build:
+    runs-on: custom-runner-linux
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: '14'
+      - run: npm install
+      - name: Run ESLint
+        # GitHub should automatically annotate the PR
+        run: npm run lint

.github/workflows/network-explorer.yml

@@ -11,7 +11,7 @@ defaults:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: custom-runner-linux
     steps:
     - uses: actions/checkout@v2
     - name: Install rsync
@@ -35,7 +35,7 @@ jobs:
         SOURCE: "explorer/dist/"
         REMOTE_HOST: ${{ secrets.CI_WWW_REMOTE_HOST }}
         REMOTE_USER: ${{ secrets.CI_WWW_REMOTE_USER }}
-        TARGET: ${{ secrets.CI_WWW_REMOTE_TARGET }}/${{ env.GITHUB_REF_SLUG }}
+        TARGET: ${{ secrets.CI_WWW_REMOTE_TARGET }}/network-explorer-${{ env.GITHUB_REF_SLUG }}
         EXCLUDE: "/dist/, /node_modules/"
     - name: Keybase - Node Install
       run: npm install
@@ -44,6 +44,7 @@ jobs:
       env:
         NYM_PROJECT_NAME: "Network Explorer"
         NYM_CI_WWW_BASE: "${{ secrets.NYM_CI_WWW_BASE }}"
+        NYM_CI_WWW_LOCATION: "network-explorer-${{ env.GITHUB_REF_SLUG }}"
         GIT_COMMIT_MESSAGE: "${{ github.event.head_commit.message }}"
         GIT_BRANCH: "${GITHUB_REF##*/}"
         KEYBASE_NYMBOT_USERNAME: "${{ secrets.KEYBASE_NYMBOT_USERNAME }}"

.github/workflows/nym_wallet.yml

@@ -1,18 +1,18 @@
 name: Webdriverio tests for nym wallet
 
-on: 
- push:
+on:
+  push:
     paths:
-      - 'tauri-wallet/**'
-      
+      - "nym-wallet/**"
+
 defaults:
   run:
-    working-directory: tauri-wallet
+    working-directory: nym-wallet
 
 jobs:
   test:
     name: wallet tests
-    runs-on: ubuntu-latest 
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
 
@@ -30,8 +30,8 @@ jobs:
       - name: Install minimal stable
         uses: actions-rs/toolchain@v1
         with:
-         profile: minimal
-         toolchain: stable
+          profile: minimal
+          toolchain: stable
 
       - name: Node v16
         uses: actions/setup-node@v1
@@ -39,27 +39,32 @@ jobs:
           node-version: 16.x
 
       - name: Install yarn for building application
-        run: yarn install    
+        run: yarn install
 
       - name: Build application
         run: yarn run webpack:build & yarn run tauri:build
 
+      - name: Check binary exists
+        run: |
+          cd target/release/
+          (test -f nym-wallet && echo nym binary exists) || echo wallet does not exist
+
       - name: Install dependencies
         run: yarn install
-        working-directory: tauri-wallet/webdriver
+        working-directory: nym-wallet/webdriver
 
       - name: Remove existing user datafile
         uses: JesseTG/rm@v1.0.2
         with:
-          path: tauri-wallet/webdriver/common/data/user-data.json
+          path: nym-wallet/webdriver/common/data/user-data.json
 
       - name: Create user data json file
         id: create-json
         uses: jsdaniell/create-json@1.1.2
         with:
-           name: "user-data.json"
-           json: ${{ secrets.WALLET_USERDATA }}
-           dir: 'tauri-wallet/webdriver/common/data/'
+          name: "user-data.json"
+          json: ${{ secrets.WALLET_USERDATA }}
+          dir: "nym-wallet/webdriver/common/data/"
 
       - name: Install tauri-driver
         uses: actions-rs/cargo@v1
@@ -68,5 +73,5 @@ jobs:
           args: tauri-driver
 
       - name: Launch tests
-        run: xvfb-run yarn test:newuser
-        working-directory: tauri-wallet/webdriver
+        run: xvfb-run yarn test:runall
+        working-directory: nym-wallet/webdriver

.github/workflows/support-files/messages/success

@@ -1,5 +1,5 @@
 🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩🟩
-> :rocket: {{ env.NYM_PROJECT_NAME }}  ➡️➡️➡️➡️➡️ **View output:** https://{{ env.GITHUB_REF_SLUG }}.{{ env.NYM_CI_WWW_BASE }}/
+> :rocket: {{ env.NYM_PROJECT_NAME }}  ➡️➡️➡️➡️➡️ **View output:** https://{{ env.NYM_CI_WWW_LOCATION }}.{{ env.NYM_CI_WWW_BASE }}/
 > ✅ **SUCCESS**
 > `branch` {{ env.GITHUB_SERVER_URL }}/{{ env.GITHUB_REPOSITORY }}/tree/{{ env.GIT_BRANCH_NAME }}
 > `commit` {{ env.GITHUB_SERVER_URL }}/{{ env.GITHUB_REPOSITORY }}/commit/{{ env.GITHUB_SHA }}

.github/workflows/tauri-wallet-publish.yml

@@ -0,0 +1,12 @@
+name: Publish Tauri Wallet
+on:
+  push:
+    tags:
+      - nym-wallet-*
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Run a one-line script
+        run: echo Hello, world!

.github/workflows/tauri-wallet-types.yml

@@ -1,10 +1,17 @@
 name: Generate TS types
 
-on: push
+on:
+  push:
+    paths-ignore:
+      - "explorer/**"
+  pull_request:
+    paths-ignore:
+      - "explorer/**"
 
 jobs:
-  tauri-wallet-types:
+  nym-wallet-types:
     runs-on: ubuntu-latest
+    if: ${{ github.event_name != 'pull_request' }}
     steps:
       - name: Prepare
         run: sudo apt-get update && sudo apt-get install -y libpango1.0-dev libatk1.0-dev libgdk-pixbuf2.0-dev libsoup2.4-dev librust-gdk-dev libwebkit2gtk-4.0-dev
@@ -13,10 +20,10 @@ jobs:
         with:
           toolchain: stable
       - name: Generate TS
-        run: cd tauri-wallet/src-tauri && cargo test
+        run: cd nym-wallet/src-tauri && cargo test
       - uses: EndBug/add-and-commit@v7.2.1 # https://github.com/marketplace/actions/add-commit
         with:
-          add: '["tauri-wallet"]'
-          message: '[ci skip] Generate TS types'
+          add: '["nym-wallet"]'
+          message: "[ci skip] Generate TS types"
         env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/wasm_client_build.yml

@@ -1,6 +1,9 @@
 name: Wasm Client
 
-on: [push, pull_request]
+on:
+  pull_request:
+    paths-ignore:
+      - 'explorer/**'
 
 jobs:
   wasm:
@@ -16,10 +19,11 @@ jobs:
           override: true
           components: rustfmt, clippy
 
-      - uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --manifest-path clients/webassembly/Cargo.toml --target wasm32-unknown-unknown
+# token credentials (non-coconut) don't work for wasm right now
+#      - uses: actions-rs/cargo@v1
+#        with:
+#          command: build
+#          args: --manifest-path clients/webassembly/Cargo.toml --target wasm32-unknown-unknown
 
       - uses: actions-rs/cargo@v1
         with:
@@ -41,4 +45,4 @@ jobs:
 #      - uses: actions-rs/cargo@v1
 #        with:
 #          command: clippy
-#          args: --manifest-path clients/webassembly/Cargo.toml --target wasm32-unknown-unknown -- -D warnings
+#          args: --manifest-path clients/webassembly/Cargo.toml --target wasm32-unknown-unknown -- -D warnings

.gitignore

@@ -11,7 +11,6 @@ target
 /.vscode/settings.json
 validator/.vscode
 sample-configs/validator-config.toml
-.vscode
 scripts/deploy_qa.sh
 scripts/run_gate.sh
 scripts/run_mix.sh
@@ -25,8 +24,14 @@ v6-topology.json
 /explorer/downloads/topology.json
 /explorer/public/downloads/mixmining.json
 /explorer/public/downloads/topology.json
+/nym-wallet/dist/*
 /clients/validator/examples/nym-driver-example/current-contract.txt
 validator-api/v4.json
 validator-api/v6.json
 **/node_modules
 validator-api/keypair
+contracts/mixnet/code_id
+contracts/mixnet/Justfile
+contracts/mixnet/Makefile
+validator-config
+*.patch

Cargo.toml

@@ -4,6 +4,7 @@
 [profile.release]
 panic = "abort"
 opt-level = "s"
+overflow-checks = true
 
 [profile.dev]
 panic = "abort"
@@ -24,10 +25,12 @@ members = [
     "common/config",
     "common/credentials",
     "common/crypto",
+    "common/erc20-bridge-contract",
     "common/mixnet-contract",
     "common/mixnode-common",
     "common/network-defaults",
     "common/nonexhaustive-delayqueue",
+    "common/nymcoconut",
     "common/nymsphinx",
     "common/nymsphinx/acknowledgements",
     "common/nymsphinx/addressing",
@@ -61,4 +64,4 @@ default-members = [
     "validator-api",
 ]
 
-exclude = ["explorer", "contracts"]
+exclude = ["explorer", "contracts", "tokenomics-py"]

README.md

@@ -5,8 +5,6 @@ SPDX-License-Identifier: Apache-2.0
 
 ## The Nym Privacy Platform
 
-This repository contains the Nym mixnet.
-
 The platform is composed of multiple Rust crates. Top-level executable binary crates include:
 
 * nym-mixnode - shuffles [Sphinx](https://github.com/nymtech/sphinx) packets together to provide privacy against network-level attackers.
@@ -33,6 +31,45 @@ There's a `.env.sample-dev` file provided which you can rename to `.env` if you
 
 You can chat to us in [Keybase](https://keybase.io). Download their chat app, then click **Teams -> Join a team**. Type **nymtech.friends** into the team name and hit **continue**. For general chat, hang out in the **#general** channel. Our development takes places in the **#dev** channel. Node operators should be in the **#node-operators** channel.
 
+### Rewards
+
+Node, node operator and delegator rewards are determined according to the principles laid out in the section 6 of [Nym Whitepaper](https://nymtech.net/nym-whitepaper.pdf). Below is a TLDR of the variables and formulas involved in calculating the epoch rewards. Initial reward pool is set to 250 million Nym, making the circulating supply 750 million Nym.
+
+|Symbol|Definition|
+|---|---|
+|<img src="https://render.githubusercontent.com/render/math?math=R">|global share of rewards available, starts at 2% of the reward pool. 
+|<img src="https://render.githubusercontent.com/render/math?math=R_{i}">|node reward for mixnode `i`.
+|<img src="https://render.githubusercontent.com/render/math?math=\sigma_{i}">|ratio of total node stake (node bond + all delegations) to the token circulating supply.
+|<img src="https://render.githubusercontent.com/render/math?math=\lambda_{i}">|ratio of stake operator has plaged to their node to the token circulating supply.
+|<img src="https://render.githubusercontent.com/render/math?math=\omega_{i}">|fraction of total effort undertaken by node `i`, set to `1/k` in testnet Milhon.
+|<img src="https://render.githubusercontent.com/render/math?math=k">|number of nodes stakeholders are incentivised to create, set by the validators, a matter of governance. Currently determined by the `active set` size, and set to 5000 in testnet Milhon.
+|<img src="https://render.githubusercontent.com/render/math?math=\alpha">|Sybil attack resistance parameter - the higher this parameter is set the stronger the reduction in competitivness gets for a Sybil attacker.
+|<img src="https://render.githubusercontent.com/render/math?math=PM_{i}">|declared profit margin of operator `i`, defaults to 10% in testnet Milhon.
+|<img src="https://render.githubusercontent.com/render/math?math=PF_{i}">|uptime of node `i`, scaled to 0 - 1, for the rewarding epoch
+|<img src="https://render.githubusercontent.com/render/math?math=PP_{i}">|cost of operating node `i` for the duration of the rewarding eopoch, set to 40 Nym for testnet Milhon.
+
+Node reward for node `i` is determined as:
+
+<img src="https://render.githubusercontent.com/render/math?math=R_{i}=PF_{i} \cdot R \cdot (\sigma^'_{i} \cdot \omega_{i} \cdot k %2b \alpha \cdot \lambda^'_{i} \cdot \sigma^'_{i} \cdot k)/(1 %2b \alpha)">
+
+where:
+
+<img src="https://render.githubusercontent.com/render/math?math=\sigma^'_{i} = min\{\sigma_{i}, 1/k\}">
+
+and
+
+<img src="https://render.githubusercontent.com/render/math?math=\lambda^'_{i} = min\{\lambda_{i}, 1/k\}">
+
+Operator of node `i` is credited with the following amount:
+
+<img src="https://render.githubusercontent.com/render/math?math=min\{PP_{i},R_{i})\} %2b max\{0, (PM_{i} %2b (1 - PM_{i}) \cdot \lambda_{i}/\delta_{i}) \cdot (R_{i} - PP_{i})\}">
+
+Delegate with stake `s` recieves:
+
+<img src="https://render.githubusercontent.com/render/math?math=max\{0, (1-PM_{i}) \cdot (s^'/\sigma_{i}) \cdot (R_{i} - PP_{i})\}">
+
+where `s'` is stake `s` scaled over total token circulating supply.
+
 ### Licensing and copyright information
 
 This program is available as open source under the terms of the Apache 2.0 license. However, some elements are being licensed under CC0-1.0 and MIT. For accurate information, please check individual files.

clients/client-core/Cargo.toml

@@ -30,3 +30,6 @@ validator-client = { path = "../../common/client-libs/validator-client" }
 
 [dev-dependencies]
 tempfile = "3.1.0"
+
+[features]
+coconut = []

clients/client-core/src/client/topology_control.rs

@@ -257,7 +257,7 @@ impl TopologyRefresher {
             Ok(mixes) => mixes,
         };
 
-        let gateways = match self.validator_client.get_cached_active_gateways().await {
+        let gateways = match self.validator_client.get_cached_gateways().await {
             Err(err) => {
                 error!("failed to get network gateways - {}", err);
                 return None;

clients/client-core/src/config/mod.rs

@@ -22,7 +22,10 @@ const DEFAULT_MESSAGE_STREAM_AVERAGE_DELAY: Duration = Duration::from_millis(20)
 const DEFAULT_AVERAGE_PACKET_DELAY: Duration = Duration::from_millis(50);
 const DEFAULT_TOPOLOGY_REFRESH_RATE: Duration = Duration::from_secs(5 * 60); // every 5min
 const DEFAULT_TOPOLOGY_RESOLUTION_TIMEOUT: Duration = Duration::from_millis(5_000);
-const DEFAULT_GATEWAY_RESPONSE_TIMEOUT: Duration = Duration::from_millis(1_500);
+// Set this to a high value for now, so that we don't risk sporadic timeouts that might cause
+// bought bandwidth tokens to not have time to be spent; Once we remove the gateway from the
+// bandwidth bridging protocol, we can come back to a smaller timeout value
+const DEFAULT_GATEWAY_RESPONSE_TIMEOUT: Duration = Duration::from_secs(5 * 60);
 
 pub fn missing_string_value() -> String {
     MISSING_VALUE.to_string()
@@ -100,6 +103,17 @@ impl<T: NymConfig> Config<T> {
                 self::Client::<T>::default_reply_encryption_key_store_path(&id);
         }
 
+        #[cfg(not(feature = "coconut"))]
+        if self
+            .client
+            .backup_bandwidth_token_keys_dir
+            .as_os_str()
+            .is_empty()
+        {
+            self.client.backup_bandwidth_token_keys_dir =
+                self::Client::<T>::default_backup_bandwidth_token_keys_dir(&id);
+        }
+
         self.client.id = id;
     }
 
@@ -111,6 +125,16 @@ impl<T: NymConfig> Config<T> {
         self.client.gateway_listener = gateway_listener.into();
     }
 
+    #[cfg(not(feature = "coconut"))]
+    pub fn with_eth_private_key<S: Into<String>>(&mut self, eth_private_key: S) {
+        self.client.eth_private_key = eth_private_key.into();
+    }
+
+    #[cfg(not(feature = "coconut"))]
+    pub fn with_eth_endpoint<S: Into<String>>(&mut self, eth_endpoint: S) {
+        self.client.eth_endpoint = eth_endpoint.into();
+    }
+
     pub fn set_custom_validator_apis(&mut self, validator_api_urls: Vec<Url>) {
         self.client.validator_api_urls = validator_api_urls;
     }
@@ -173,6 +197,21 @@ impl<T: NymConfig> Config<T> {
         self.client.gateway_listener.clone()
     }
 
+    #[cfg(not(feature = "coconut"))]
+    pub fn get_backup_bandwidth_token_keys_dir(&self) -> PathBuf {
+        self.client.backup_bandwidth_token_keys_dir.clone()
+    }
+
+    #[cfg(not(feature = "coconut"))]
+    pub fn get_eth_endpoint(&self) -> String {
+        self.client.eth_endpoint.clone()
+    }
+
+    #[cfg(not(feature = "coconut"))]
+    pub fn get_eth_private_key(&self) -> String {
+        self.client.eth_private_key.clone()
+    }
+
     // Debug getters
     pub fn get_average_packet_delay(&self) -> Duration {
         self.debug.average_packet_delay
@@ -268,6 +307,20 @@ pub struct Client<T> {
     /// Address of the gateway listener to which all client requests should be sent.
     gateway_listener: String,
 
+    /// Path to directory containing public/private keys used for bandwidth token purchase.
+    /// Those are saved in case of emergency, to be able to reclaim bandwidth tokens.
+    /// The public key is the name of the file, while the private key is the content.
+    #[cfg(not(feature = "coconut"))]
+    backup_bandwidth_token_keys_dir: PathBuf,
+
+    /// Ethereum private key.
+    #[cfg(not(feature = "coconut"))]
+    eth_private_key: String,
+
+    /// Address to an Ethereum full node.
+    #[cfg(not(feature = "coconut"))]
+    eth_endpoint: String,
+
     /// nym_home_directory specifies absolute path to the home nym Clients directory.
     /// It is expected to use default value and hence .toml file should not redefine this field.
     nym_root_directory: PathBuf,
@@ -292,6 +345,12 @@ impl<T: NymConfig> Default for Client<T> {
             reply_encryption_key_store_path: Default::default(),
             gateway_id: "".to_string(),
             gateway_listener: "".to_string(),
+            #[cfg(not(feature = "coconut"))]
+            backup_bandwidth_token_keys_dir: Default::default(),
+            #[cfg(not(feature = "coconut"))]
+            eth_private_key: "".to_string(),
+            #[cfg(not(feature = "coconut"))]
+            eth_endpoint: "".to_string(),
             nym_root_directory: T::default_root_directory(),
             super_struct: Default::default(),
         }
@@ -326,6 +385,11 @@ impl<T: NymConfig> Client<T> {
     fn default_reply_encryption_key_store_path(id: &str) -> PathBuf {
         T::default_data_directory(Some(id)).join("reply_key_store")
     }
+
+    #[cfg(not(feature = "coconut"))]
+    fn default_backup_bandwidth_token_keys_dir(id: &str) -> PathBuf {
+        T::default_data_directory(Some(id)).join("backup_bandwidth_token_keys")
+    }
 }
 
 #[derive(Debug, Default, Deserialize, PartialEq, Serialize)]

clients/native/Cargo.toml

@@ -3,6 +3,7 @@ name = "nym-client"
 version = "0.11.0"
 authors = ["Dave Hrycyszyn <futurechimp@users.noreply.github.com>", "Jędrzej Stuczyński <andrew@nymtech.net>"]
 edition = "2018"
+rust-version = "1.56"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
@@ -23,7 +24,7 @@ dirs = "3.0" # for determining default store directories in config
 dotenv = "0.15.0" # for obtaining environmental variables (only used for RUST_LOG for time being)
 log = "0.4" # self explanatory
 pretty_env_logger = "0.4" # for formatting log messages
-rand = {version = "0.7.3", features = ["wasm-bindgen"]} # rng-related traits + some rng implementation to use
+rand = { version = "0.7.3", features = ["wasm-bindgen"] } # rng-related traits + some rng implementation to use
 serde = { version = "1.0.104", features = ["derive"] } # for config serialization/deserialization
 sled = "0.34" # for storage of replySURB decryption keys
 tokio = { version = "1.4", features = ["rt-multi-thread", "net", "signal"] } # async runtime
@@ -43,6 +44,7 @@ topology = { path = "../../common/topology" }
 websocket-requests = { path = "websocket-requests" }
 validator-client = { path = "../../common/client-libs/validator-client" }
 version-checker = { path = "../../common/version-checker" }
+network-defaults = { path = "../../common/network-defaults" }
 
 [features]
 coconut = ["coconut-interface", "credentials", "gateway-requests/coconut", "gateway-client/coconut"]

clients/native/src/client/config/template.rs

@@ -42,6 +42,17 @@ public_encryption_key_file = '{{ client.public_encryption_key_file }}'
 # sent but not received back.
 reply_encryption_key_store_path = '{{ client.reply_encryption_key_store_path }}'
 
+# Path to directory containing public/private keys used for bandwidth token purchase.
+# Those are saved in case of emergency, to be able to reclaim bandwidth tokens.
+# The public key is the name of the file, while the private key is the content.
+backup_bandwidth_token_keys_dir = '{{ client.backup_bandwidth_token_keys_dir }}'
+
+# Ethereum private key.
+eth_private_key = '{{ client.eth_private_key }}'
+
+# Addess to an Ethereum full node.
+eth_endpoint = '{{ client.eth_endpoint }}'
+
 ##### additional client config options #####
 
 # ID of the gateway from which the client should be fetching messages.

clients/native/src/client/mod.rs

@@ -1,8 +1,6 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
-use crate::client::config::{Config, SocketType};
-use crate::websocket;
 use client_core::client::cover_traffic_stream::LoopCoverTrafficStream;
 use client_core::client::inbound_messages::{
     InputMessage, InputMessageReceiver, InputMessageSender,
@@ -24,6 +22,7 @@ use client_core::client::topology_control::{
 use client_core::config::persistence::key_pathfinder::ClientKeyPathfinder;
 use crypto::asymmetric::identity;
 use futures::channel::mpsc;
+use gateway_client::bandwidth::BandwidthController;
 use gateway_client::{
     AcknowledgementReceiver, AcknowledgementSender, GatewayClient, MixnetMessageReceiver,
     MixnetMessageSender,
@@ -35,10 +34,8 @@ use nymsphinx::anonymous_replies::ReplySurb;
 use nymsphinx::receiver::ReconstructedMessage;
 use tokio::runtime::Runtime;
 
-#[cfg(feature = "coconut")]
-use coconut_interface::Credential;
-#[cfg(feature = "coconut")]
-use credentials::{bandwidth::prepare_for_spending, obtain_aggregate_verification_key};
+use crate::client::config::{Config, SocketType};
+use crate::websocket;
 
 pub(crate) mod config;
 
@@ -168,31 +165,6 @@ impl NymClient {
         .start(self.runtime.handle())
     }
 
-    #[cfg(feature = "coconut")]
-    async fn prepare_coconut_credential(&self) -> Credential {
-        let verification_key = obtain_aggregate_verification_key(
-            &self.config.get_base().get_validator_api_endpoints(),
-        )
-        .await
-        .expect("could not obtain aggregate verification key of validators");
-
-        let bandwidth_credential = credentials::bandwidth::obtain_signature(
-            &self.key_manager.identity_keypair().public_key().to_bytes(),
-            &self.config.get_base().get_validator_api_endpoints(),
-        )
-        .await
-        .expect("could not obtain bandwidth credential");
-        // the above would presumably be loaded from a file
-
-        // the below would only be executed once we know where we want to spend it (i.e. which gateway and stuff)
-        prepare_for_spending(
-            &self.key_manager.identity_keypair().public_key().to_bytes(),
-            &bandwidth_credential,
-            &verification_key,
-        )
-        .expect("could not prepare out bandwidth credential for spending")
-    }
-
     fn start_gateway_client(
         &mut self,
         mixnet_message_sender: MixnetMessageSender,
@@ -212,7 +184,17 @@ impl NymClient {
 
         self.runtime.block_on(async {
             #[cfg(feature = "coconut")]
-            let coconut_credential = self.prepare_coconut_credential().await;
+            let bandwidth_controller = BandwidthController::new(
+                self.config.get_base().get_validator_api_endpoints(),
+                *self.key_manager.identity_keypair().public_key(),
+            );
+            #[cfg(not(feature = "coconut"))]
+            let bandwidth_controller = BandwidthController::new(
+                self.config.get_base().get_eth_endpoint(),
+                self.config.get_base().get_eth_private_key(),
+                self.config.get_base().get_backup_bandwidth_token_keys_dir(),
+            )
+            .expect("Could not create bandwidth controller");
 
             let mut gateway_client = GatewayClient::new(
                 gateway_address,
@@ -222,13 +204,11 @@ impl NymClient {
                 mixnet_message_sender,
                 ack_sender,
                 self.config.get_base().get_gateway_response_timeout(),
+                Some(bandwidth_controller),
             );
 
             gateway_client
-                .authenticate_and_start(
-                    #[cfg(feature = "coconut")]
-                    Some(coconut_credential),
-                )
+                .authenticate_and_start()
                 .await
                 .expect("could not authenticate and start up the gateway connection");
 

clients/native/src/commands/init.rs

@@ -1,15 +1,23 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
-use crate::client::config::Config;
-use crate::commands::override_config;
 use clap::{App, Arg, ArgMatches};
 use client_core::client::key_manager::KeyManager;
 use client_core::config::persistence::key_pathfinder::ClientKeyPathfinder;
+#[cfg(feature = "coconut")]
+use coconut_interface::{hash_to_scalar, Credential, Parameters};
 use config::NymConfig;
+#[cfg(feature = "coconut")]
+use credentials::coconut::bandwidth::{
+    obtain_signature, prepare_for_spending, BandwidthVoucherAttributes, TOTAL_ATTRIBUTES,
+};
+#[cfg(feature = "coconut")]
+use credentials::obtain_aggregate_verification_key;
 use crypto::asymmetric::{encryption, identity};
 use gateway_client::GatewayClient;
 use gateway_requests::registration::handshake::SharedKeys;
+#[cfg(feature = "coconut")]
+use network_defaults::BANDWIDTH_VALUE;
 use nymsphinx::addressing::clients::Recipient;
 use nymsphinx::addressing::nodes::NodeIdentity;
 use rand::rngs::OsRng;
@@ -21,8 +29,11 @@ use std::time::Duration;
 use topology::{filter::VersionFilterable, gateway};
 use url::Url;
 
+use crate::client::config::Config;
+use crate::commands::override_config;
+
 pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
-    App::new("init")
+    let app = App::new("init")
         .about("Initialise a Nym client. Do this first!")
         .arg(Arg::with_name("id")
             .long("id")
@@ -36,9 +47,9 @@ pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
             .takes_value(true)
         )
         .arg(Arg::with_name("validators")
-                .long("validators")
-                .help("Comma separated list of rest endpoints of the validators")
-                .takes_value(true),
+                 .long("validators")
+                 .help("Comma separated list of rest endpoints of the validators")
+                 .takes_value(true),
         )
         .arg(Arg::with_name("disable-socket")
             .long("disable-socket")
@@ -54,7 +65,51 @@ pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
             .long("fastmode")
             .hidden(true) // this will prevent this flag from being displayed in `--help`
             .help("Mostly debug-related option to increase default traffic rate so that you would not need to modify config post init")
-        )
+        );
+    #[cfg(not(feature = "coconut"))]
+        let app = app
+        .arg(Arg::with_name("eth_endpoint")
+            .long("eth_endpoint")
+            .help("URL of an Ethereum full node that we want to use for getting bandwidth tokens from ERC20 tokens")
+            .takes_value(true)
+            .required(true))
+        .arg(Arg::with_name("eth_private_key")
+            .long("eth_private_key")
+            .help("Ethereum private key used for obtaining bandwidth tokens from ERC20 tokens")
+            .takes_value(true)
+            .required(true));
+
+    app
+}
+
+// this behaviour should definitely be changed, we shouldn't
+// need to get bandwidth credential for registration
+#[cfg(feature = "coconut")]
+async fn _prepare_temporary_credential(validators: &[Url], raw_identity: &[u8]) -> Credential {
+    let verification_key = obtain_aggregate_verification_key(validators)
+        .await
+        .expect("could not obtain aggregate verification key of validators");
+
+    let params = Parameters::new(TOTAL_ATTRIBUTES).unwrap();
+    let bandwidth_credential_attributes = BandwidthVoucherAttributes {
+        serial_number: params.random_scalar(),
+        binding_number: params.random_scalar(),
+        voucher_value: hash_to_scalar(BANDWIDTH_VALUE.to_be_bytes()),
+        voucher_info: hash_to_scalar(String::from("BandwidthVoucher").as_bytes()),
+    };
+
+    let bandwidth_credential =
+        obtain_signature(&params, &bandwidth_credential_attributes, validators)
+            .await
+            .expect("could not obtain bandwidth credential");
+
+    prepare_for_spending(
+        raw_identity,
+        &bandwidth_credential,
+        &bandwidth_credential_attributes,
+        &verification_key,
+    )
+    .expect("could not prepare out bandwidth credential for spending")
 }
 
 async fn register_with_gateway(

clients/native/src/commands/mod.rs

@@ -43,5 +43,14 @@ pub(crate) fn override_config(mut config: Config, matches: &ArgMatches) -> Confi
         config = config.with_port(port.unwrap());
     }
 
+    #[cfg(not(feature = "coconut"))]
+    if let Some(eth_endpoint) = matches.value_of("eth_endpoint") {
+        config.get_base_mut().with_eth_endpoint(eth_endpoint);
+    }
+    #[cfg(not(feature = "coconut"))]
+    if let Some(eth_private_key) = matches.value_of("eth_private_key") {
+        config.get_base_mut().with_eth_private_key(eth_private_key);
+    }
+
     config
 }

clients/native/src/commands/run.rs

@@ -10,7 +10,7 @@ use log::*;
 use version_checker::is_minor_version_compatible;
 
 pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
-    App::new("run")
+    let app = App::new("run")
         .about("Run the Nym client with provided configuration client optionally overriding set parameters")
         .arg(Arg::with_name("id")
             .long("id")
@@ -38,7 +38,19 @@ pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
             .long("port")
             .help("Port for the socket (if applicable) to listen on")
             .takes_value(true)
-        )
+        );
+    #[cfg(not(feature = "coconut"))]
+        let app = app
+        .arg(Arg::with_name("eth_endpoint")
+            .long("eth_endpoint")
+            .help("URL of an Ethereum full node that we want to use for getting bandwidth tokens from ERC20 tokens")
+            .takes_value(true))
+        .arg(Arg::with_name("eth_private_key")
+            .long("eth_private_key")
+            .help("Ethereum private key used for obtaining bandwidth tokens from ERC20 tokens")
+            .takes_value(true));
+
+    app
 }
 
 // this only checks compatibility between config the binary. It does not take into consideration

clients/native/src/websocket/mod.rs

@@ -1,8 +1,8 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
-pub(crate) mod handler;
-pub(crate) mod listener;
-
 pub(crate) use handler::Handler;
 pub(crate) use listener::Listener;
+
+pub(crate) mod handler;
+pub(crate) mod listener;

clients/socks5/Cargo.toml

@@ -3,6 +3,7 @@ name = "nym-socks5-client"
 version = "0.11.0"
 authors = ["Dave Hrycyszyn <futurechimp@users.noreply.github.com>"]
 edition = "2018"
+rust-version = "1.56"
 
 [lib]
 name = "nym_socks5"
@@ -31,13 +32,14 @@ crypto = { path = "../../common/crypto" }
 gateway-client = { path = "../../common/client-libs/gateway-client" }
 gateway-requests = { path = "../../gateway/gateway-requests" }
 nymsphinx = { path = "../../common/nymsphinx" }
-ordered-buffer = {path = "../../common/socks5/ordered-buffer"}
+ordered-buffer = { path = "../../common/socks5/ordered-buffer" }
 socks5-requests = { path = "../../common/socks5/requests" }
 topology = { path = "../../common/topology" }
 pemstore = { path = "../../common/pemstore" }
 proxy-helpers = { path = "../../common/socks5/proxy-helpers" }
 validator-client = { path = "../../common/client-libs/validator-client" }
 version-checker = { path = "../../common/version-checker" }
+network-defaults = { path = "../../common/network-defaults" }
 
 [features]
 coconut = ["coconut-interface", "credentials", "gateway-requests/coconut", "gateway-client/coconut"]

clients/socks5/src/client/config/template.rs

@@ -42,6 +42,17 @@ public_encryption_key_file = '{{ client.public_encryption_key_file }}'
 # sent but not received back.
 reply_encryption_key_store_path = '{{ client.reply_encryption_key_store_path }}'
 
+# Path to directory containing public/private keys used for bandwidth token purchase.
+# Those are saved in case of emergency, to be able to reclaim bandwidth tokens.
+# The public key is the name of the file, while the private key is the content.
+backup_bandwidth_token_keys_dir = '{{ client.backup_bandwidth_token_keys_dir }}'
+
+# Ethereum private key.
+eth_private_key = '{{ client.eth_private_key }}'
+
+# Addess to an Ethereum full node.
+eth_endpoint = '{{ client.eth_endpoint }}'
+
 ##### additional client config options #####
 
 # ID of the gateway from which the client should be fetching messages.

clients/socks5/src/client/mod.rs

@@ -1,11 +1,6 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
-use crate::client::config::Config;
-use crate::socks::{
-    authentication::{AuthenticationMethods, Authenticator, User},
-    server::SphinxSocksServer,
-};
 use client_core::client::cover_traffic_stream::LoopCoverTrafficStream;
 use client_core::client::inbound_messages::{
     InputMessage, InputMessageReceiver, InputMessageSender,
@@ -25,6 +20,7 @@ use client_core::client::topology_control::{
 use client_core::config::persistence::key_pathfinder::ClientKeyPathfinder;
 use crypto::asymmetric::identity;
 use futures::channel::mpsc;
+use gateway_client::bandwidth::BandwidthController;
 use gateway_client::{
     AcknowledgementReceiver, AcknowledgementSender, GatewayClient, MixnetMessageReceiver,
     MixnetMessageSender,
@@ -34,10 +30,11 @@ use nymsphinx::addressing::clients::Recipient;
 use nymsphinx::addressing::nodes::NodeIdentity;
 use tokio::runtime::Runtime;
 
-#[cfg(feature = "coconut")]
-use coconut_interface::Credential;
-#[cfg(feature = "coconut")]
-use credentials::{bandwidth::prepare_for_spending, obtain_aggregate_verification_key};
+use crate::client::config::Config;
+use crate::socks::{
+    authentication::{AuthenticationMethods, Authenticator, User},
+    server::SphinxSocksServer,
+};
 
 pub(crate) mod config;
 
@@ -156,31 +153,6 @@ impl NymClient {
         .start(self.runtime.handle())
     }
 
-    #[cfg(feature = "coconut")]
-    async fn prepare_coconut_credential(&self) -> Credential {
-        let verification_key = obtain_aggregate_verification_key(
-            &self.config.get_base().get_validator_api_endpoints(),
-        )
-        .await
-        .expect("could not obtain aggregate verification key of validators");
-
-        let bandwidth_credential = credentials::bandwidth::obtain_signature(
-            &self.key_manager.identity_keypair().public_key().to_bytes(),
-            &self.config.get_base().get_validator_api_endpoints(),
-        )
-        .await
-        .expect("could not obtain bandwidth credential");
-        // the above would presumably be loaded from a file
-
-        // the below would only be executed once we know where we want to spend it (i.e. which gateway and stuff)
-        prepare_for_spending(
-            &self.key_manager.identity_keypair().public_key().to_bytes(),
-            &bandwidth_credential,
-            &verification_key,
-        )
-        .expect("could not prepare out bandwidth credential for spending")
-    }
-
     fn start_gateway_client(
         &mut self,
         mixnet_message_sender: MixnetMessageSender,
@@ -200,7 +172,17 @@ impl NymClient {
 
         self.runtime.block_on(async {
             #[cfg(feature = "coconut")]
-            let coconut_credential = self.prepare_coconut_credential().await;
+            let bandwidth_controller = BandwidthController::new(
+                self.config.get_base().get_validator_api_endpoints(),
+                *self.key_manager.identity_keypair().public_key(),
+            );
+            #[cfg(not(feature = "coconut"))]
+            let bandwidth_controller = BandwidthController::new(
+                self.config.get_base().get_eth_endpoint(),
+                self.config.get_base().get_eth_private_key(),
+                self.config.get_base().get_backup_bandwidth_token_keys_dir(),
+            )
+            .expect("Could not create bandwidth controller");
 
             let mut gateway_client = GatewayClient::new(
                 gateway_address,
@@ -210,13 +192,11 @@ impl NymClient {
                 mixnet_message_sender,
                 ack_sender,
                 self.config.get_base().get_gateway_response_timeout(),
+                Some(bandwidth_controller),
             );
 
             gateway_client
-                .authenticate_and_start(
-                    #[cfg(feature = "coconut")]
-                    Some(coconut_credential),
-                )
+                .authenticate_and_start()
                 .await
                 .expect("could not authenticate and start up the gateway connection");
 

clients/socks5/src/commands/init.rs

@@ -1,15 +1,23 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
-use crate::client::config::Config;
-use crate::commands::override_config;
 use clap::{App, Arg, ArgMatches};
 use client_core::client::key_manager::KeyManager;
 use client_core::config::persistence::key_pathfinder::ClientKeyPathfinder;
+#[cfg(feature = "coconut")]
+use coconut_interface::{hash_to_scalar, Credential, Parameters};
 use config::NymConfig;
+#[cfg(feature = "coconut")]
+use credentials::coconut::bandwidth::{
+    obtain_signature, prepare_for_spending, BandwidthVoucherAttributes, TOTAL_ATTRIBUTES,
+};
+#[cfg(feature = "coconut")]
+use credentials::obtain_aggregate_verification_key;
 use crypto::asymmetric::{encryption, identity};
 use gateway_client::GatewayClient;
 use gateway_requests::registration::handshake::SharedKeys;
+#[cfg(feature = "coconut")]
+use network_defaults::BANDWIDTH_VALUE;
 use nymsphinx::addressing::clients::Recipient;
 use nymsphinx::addressing::nodes::NodeIdentity;
 use rand::{prelude::SliceRandom, rngs::OsRng, thread_rng};
@@ -19,8 +27,11 @@ use std::time::Duration;
 use topology::{filter::VersionFilterable, gateway};
 use url::Url;
 
+use crate::client::config::Config;
+use crate::commands::override_config;
+
 pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
-    App::new("init")
+    let app = App::new("init")
         .about("Initialise a Nym client. Do this first!")
         .arg(Arg::with_name("id")
             .long("id")
@@ -40,9 +51,9 @@ pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
             .takes_value(true)
         )
         .arg(Arg::with_name("validators")
-                .long("validators")
-                .help("Comma separated list of rest endpoints of the validators")
-                .takes_value(true),
+                 .long("validators")
+                 .help("Comma separated list of rest endpoints of the validators")
+                 .takes_value(true),
         )
         .arg(Arg::with_name("port")
             .short("p")
@@ -54,7 +65,51 @@ pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
             .long("fastmode")
             .hidden(true) // this will prevent this flag from being displayed in `--help`
             .help("Mostly debug-related option to increase default traffic rate so that you would not need to modify config post init")
-        )
+        );
+    #[cfg(not(feature = "coconut"))]
+        let app = app
+        .arg(Arg::with_name("eth_endpoint")
+            .long("eth_endpoint")
+            .help("URL of an Ethereum full node that we want to use for getting bandwidth tokens from ERC20 tokens")
+            .takes_value(true)
+            .required(true))
+        .arg(Arg::with_name("eth_private_key")
+            .long("eth_private_key")
+            .help("Ethereum private key used for obtaining bandwidth tokens from ERC20 tokens")
+            .takes_value(true)
+            .required(true));
+
+    app
+}
+
+// this behaviour should definitely be changed, we shouldn't
+// need to get bandwidth credential for registration
+#[cfg(feature = "coconut")]
+async fn _prepare_temporary_credential(validators: &[Url], raw_identity: &[u8]) -> Credential {
+    let verification_key = obtain_aggregate_verification_key(validators)
+        .await
+        .expect("could not obtain aggregate verification key of validators");
+
+    let params = Parameters::new(TOTAL_ATTRIBUTES).unwrap();
+    let bandwidth_credential_attributes = BandwidthVoucherAttributes {
+        serial_number: params.random_scalar(),
+        binding_number: params.random_scalar(),
+        voucher_value: hash_to_scalar(BANDWIDTH_VALUE.to_be_bytes()),
+        voucher_info: hash_to_scalar("BandwidthVoucher"),
+    };
+
+    let bandwidth_credential =
+        obtain_signature(&params, &bandwidth_credential_attributes, validators)
+            .await
+            .expect("could not obtain bandwidth credential");
+
+    prepare_for_spending(
+        raw_identity,
+        &bandwidth_credential,
+        &bandwidth_credential_attributes,
+        &verification_key,
+    )
+    .expect("could not prepare out bandwidth credential for spending")
 }
 
 async fn register_with_gateway(

clients/socks5/src/commands/mod.rs

@@ -39,5 +39,14 @@ pub(crate) fn override_config(mut config: Config, matches: &ArgMatches) -> Confi
         config = config.with_port(port.unwrap());
     }
 
+    #[cfg(not(feature = "coconut"))]
+    if let Some(eth_endpoint) = matches.value_of("eth_endpoint") {
+        config.get_base_mut().with_eth_endpoint(eth_endpoint);
+    }
+    #[cfg(not(feature = "coconut"))]
+    if let Some(eth_private_key) = matches.value_of("eth_private_key") {
+        config.get_base_mut().with_eth_private_key(eth_private_key);
+    }
+
     config
 }

clients/socks5/src/commands/run.rs

@@ -10,7 +10,7 @@ use log::*;
 use version_checker::is_minor_version_compatible;
 
 pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
-    App::new("run")
+    let app = App::new("run")
         .about("Run the Nym client with provided configuration client optionally overriding set parameters")
         .arg(Arg::with_name("id")
             .long("id")
@@ -44,7 +44,19 @@ pub fn command_args<'a, 'b>() -> clap::App<'a, 'b> {
             .long("port")
             .help("Port for the socket to listen on")
             .takes_value(true)
-        )
+        );
+    #[cfg(not(feature = "coconut"))]
+    let app = app
+        .arg(Arg::with_name("eth_endpoint")
+            .long("eth_endpoint")
+            .help("URL of an Ethereum full node that we want to use for getting bandwidth tokens from ERC20 tokens")
+            .takes_value(true))
+        .arg(Arg::with_name("eth_private_key")
+            .long("eth_private_key")
+            .help("Ethereum private key used for obtaining bandwidth tokens from ERC20 tokens")
+            .takes_value(true));
+
+    app
 }
 
 // this only checks compatibility between config the binary. It does not take into consideration

clients/tauri-client/src-tauri/src/main.rs

@@ -3,21 +3,24 @@
   windows_subsystem = "windows"
 )]
 
+use std::sync::Arc;
+
+use tokio::sync::RwLock;
+use url::Url;
+
 use coconut_interface::{
   self, hash_to_scalar, Attribute, Credential, Parameters, Signature, Theta, VerificationKey,
 };
 use credentials::{obtain_aggregate_signature, obtain_aggregate_verification_key};
-use std::sync::Arc;
-use tokio::sync::RwLock;
-use url::Url;
 
 struct State {
   signatures: Vec<Signature>,
   n_attributes: u32,
   params: Parameters,
-  public_attributes_bytes: Vec<Vec<u8>>,
-  public_attributes: Vec<Attribute>,
-  private_attributes: Vec<Attribute>,
+  serial_number: Attribute,
+  binding_number: Attribute,
+  voucher_value: Attribute,
+  voucher_info: Attribute,
   aggregated_verification_key: Option<VerificationKey>,
 }
 
@@ -37,9 +40,10 @@ impl State {
       signatures: Vec::new(),
       n_attributes,
       params,
-      public_attributes_bytes,
-      public_attributes,
-      private_attributes,
+      serial_number: private_attributes[0],
+      binding_number: private_attributes[1],
+      voucher_value: public_attributes[0],
+      voucher_info: public_attributes[1],
       aggregated_verification_key: None,
     }
   }
@@ -63,8 +67,8 @@ async fn randomise_credential(
 ) -> Result<Vec<Signature>, String> {
   let mut state = state.write().await;
   let signature = state.signatures.remove(idx);
-  let new = signature.randomise(&state.params);
-  state.signatures.insert(idx, new);
+  let (new_signature, _) = signature.randomise(&state.params);
+  state.signatures.insert(idx, new_signature);
   Ok(state.signatures.clone())
 }
 
@@ -117,14 +121,15 @@ async fn prove_credential(
   let state = state.read().await;
 
   if let Some(signature) = state.signatures.get(idx) {
-    match coconut_interface::prove_credential(
+    match coconut_interface::prove_bandwidth_credential(
       &state.params,
       &verification_key,
       signature,
-      &state.private_attributes,
+      state.serial_number,
+      state.binding_number,
     ) {
       Ok(theta) => Ok(theta),
-      Err(e) => Err(format!("{}", e)),
+      Err(e) => Err(format!("{:?}", e)),
     }
   } else {
     Err("Got invalid Signature idx".to_string())
@@ -144,10 +149,15 @@ async fn verify_credential(
 
   let state = state.read().await;
 
+  let public_attributes_bytes = vec![
+    state.voucher_value.to_bytes().to_vec(),
+    state.voucher_info.to_bytes().to_vec(),
+  ];
+
   let credential = Credential::new(
     state.n_attributes,
     theta,
-    state.public_attributes_bytes.clone(),
+    public_attributes_bytes,
     state
       .signatures
       .get(idx)
@@ -164,11 +174,13 @@ async fn get_credential(
 ) -> Result<Vec<Signature>, String> {
   let guard = state.read().await;
   let parsed_urls = parse_url_validators(&validator_urls)?;
+  let public_attributes = vec![guard.voucher_value, guard.voucher_info];
+  let private_attributes = vec![guard.serial_number, guard.binding_number];
 
   let signature = obtain_aggregate_signature(
     &guard.params,
-    &guard.public_attributes,
-    &guard.private_attributes,
+    &public_attributes,
+    &private_attributes,
     &parsed_urls,
   )
   .await

clients/webassembly/Cargo.toml

@@ -7,6 +7,7 @@ keywords = ["nym", "sphinx", "wasm", "webassembly", "privacy", "client"]
 license = "Apache-2.0"
 repository = "https://github.com/nymtech/nym"
 description = "A webassembly client which can be used to interact with the the Nym privacy platform. Wasm is used for Sphinx packet generation."
+rust-version = "1.56"
 
 [lib]
 crate-type = ["cdylib", "rlib"]

clients/webassembly/src/client/mod.rs

@@ -3,6 +3,7 @@
 
 use crypto::asymmetric::{encryption, identity};
 use futures::channel::mpsc;
+use gateway_client::bandwidth::BandwidthController;
 use gateway_client::GatewayClient;
 use nymsphinx::acknowledgements::AckKey;
 use nymsphinx::addressing::clients::Recipient;
@@ -17,11 +18,6 @@ use wasm_bindgen::prelude::*;
 use wasm_bindgen_futures::spawn_local;
 use wasm_utils::{console_log, console_warn};
 
-#[cfg(feature = "coconut")]
-use coconut_interface::Credential;
-#[cfg(feature = "coconut")]
-use credentials::{bandwidth::prepare_for_spending, obtain_aggregate_verification_key};
-
 pub(crate) mod received_processor;
 
 const DEFAULT_AVERAGE_PACKET_DELAY: Duration = Duration::from_millis(200);
@@ -103,35 +99,15 @@ impl NymClient {
         self.self_recipient().to_string()
     }
 
-    #[cfg(feature = "coconut")]
-    async fn prepare_coconut_credential(validators: &[Url], identity_bytes: &[u8]) -> Credential {
-        let verification_key = obtain_aggregate_verification_key(validators)
-            .await
-            .expect("could not obtain aggregate verification key of validators");
-
-        let bandwidth_credential =
-            credentials::bandwidth::obtain_signature(identity_bytes, validators)
-                .await
-                .expect("could not obtain bandwidth credential");
-        // the above would presumably be loaded from a file
-
-        // the below would only be executed once we know where we want to spend it (i.e. which gateway and stuff)
-        prepare_for_spending(identity_bytes, &bandwidth_credential, &verification_key)
-            .expect("could not prepare out bandwidth credential for spending")
-    }
-
     // Right now it's impossible to have async exported functions to take `&self` rather than self
     pub async fn initial_setup(self) -> Self {
         #[cfg(feature = "coconut")]
-        let coconut_credential = {
-            let validator_server = self.validator_server.clone();
-            let identity_public_key = self.identity.public_key().clone();
-            Self::prepare_coconut_credential(
-                &vec![validator_server],
-                &identity_public_key.to_bytes(),
-            )
-            .await
-        };
+        let bandwidth_controller = Some(BandwidthController::new(
+            vec![self.validator_server.clone()],
+            *self.identity.public_key(),
+        ));
+        #[cfg(not(feature = "coconut"))]
+        let bandwidth_controller = None;
 
         let mut client = self.get_and_update_topology().await;
         let gateway = client.choose_gateway();
@@ -147,13 +123,11 @@ impl NymClient {
             mixnet_messages_sender,
             ack_sender,
             DEFAULT_GATEWAY_RESPONSE_TIMEOUT,
+            bandwidth_controller,
         );
 
         gateway_client
-            .authenticate_and_start(
-                #[cfg(feature = "coconut")]
-                Some(coconut_credential),
-            )
+            .authenticate_and_start()
             .await
             .expect("could not authenticate and start up the gateway connection");
 
@@ -275,11 +249,11 @@ impl NymClient {
         let validator_client = validator_client::ApiClient::new(self.validator_server.clone());
 
         let mixnodes = match validator_client.get_cached_active_mixnodes().await {
-            Err(err) => panic!("{}", err),
+            Err(err) => panic!("{:?}", err),
             Ok(mixes) => mixes,
         };
 
-        let gateways = match validator_client.get_cached_active_gateways().await {
+        let gateways = match validator_client.get_cached_gateways().await {
             Err(err) => panic!("{}", err),
             Ok(gateways) => gateways,
         };

common/client-libs/gateway-client/Cargo.toml

@@ -10,14 +10,19 @@ edition = "2018"
 # TODO: (for this and other crates), similarly to 'tokio', import only required "futures" modules rather than
 # the entire crate
 futures = "0.3"
+json = "0.12.4"
 log = "0.4"
+thiserror = "1.0"
+url = "2.2"
 rand = { version = "0.7.3", features = ["wasm-bindgen"] }
 
 # internal
+credentials = { path = "../../credentials" }
 crypto = { path = "../../crypto" }
 gateway-requests = { path = "../../../gateway/gateway-requests" }
 nymsphinx = { path = "../../nymsphinx" }
 coconut-interface = { path = "../../coconut-interface", optional = true }
+network-defaults = { path = "../../network-defaults" }
 
 [dependencies.tungstenite]
 version = "0.13"
@@ -31,6 +36,12 @@ features = ["macros", "rt", "net", "sync", "time"]
 [target."cfg(not(target_arch = \"wasm32\"))".dependencies.tokio-tungstenite]
 version = "0.14"
 
+[target."cfg(not(target_arch = \"wasm32\"))".dependencies.secp256k1]
+version = "0.20.3"
+
+[target."cfg(not(target_arch = \"wasm32\"))".dependencies.web3]
+version = "0.17.0"
+
 # wasm-only dependencies
 [target."cfg(target_arch = \"wasm32\")".dependencies.wasm-bindgen]
 version = "0.2"

common/client-libs/gateway-client/src/bandwidth.rs

@@ -0,0 +1,247 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+#[cfg(feature = "coconut")]
+use credentials::coconut::{
+    bandwidth::{
+        obtain_signature, prepare_for_spending, BandwidthVoucherAttributes, TOTAL_ATTRIBUTES,
+    },
+    utils::obtain_aggregate_verification_key,
+};
+#[cfg(not(feature = "coconut"))]
+use credentials::token::bandwidth::TokenCredential;
+#[cfg(not(feature = "coconut"))]
+use crypto::asymmetric::identity;
+use crypto::asymmetric::identity::PublicKey;
+use network_defaults::BANDWIDTH_VALUE;
+#[cfg(not(feature = "coconut"))]
+use network_defaults::{
+    eth_contract::ETH_JSON_ABI, ETH_BURN_FUNCTION_NAME, ETH_CONTRACT_ADDRESS, ETH_MIN_BLOCK_DEPTH,
+    TOKENS_TO_BURN,
+};
+#[cfg(not(feature = "coconut"))]
+use rand::rngs::OsRng;
+#[cfg(not(feature = "coconut"))]
+use secp256k1::SecretKey;
+#[cfg(not(feature = "coconut"))]
+use std::io::Write;
+#[cfg(not(feature = "coconut"))]
+use std::str::FromStr;
+#[cfg(not(feature = "coconut"))]
+use web3::{
+    contract::{Contract, Options},
+    transports::Http,
+    types::{Address, Bytes, U256, U64},
+    Web3,
+};
+
+use crate::error::GatewayClientError;
+
+#[cfg(not(feature = "coconut"))]
+pub fn eth_contract(web3: Web3<Http>) -> Contract<Http> {
+    Contract::from_json(
+        web3.eth(),
+        Address::from(ETH_CONTRACT_ADDRESS),
+        json::parse(ETH_JSON_ABI)
+            .expect("Invalid json abi")
+            .dump()
+            .as_bytes(),
+    )
+    .expect("Invalid json abi")
+}
+
+#[derive(Clone)]
+pub struct BandwidthController {
+    #[cfg(feature = "coconut")]
+    validator_endpoints: Vec<url::Url>,
+    #[cfg(feature = "coconut")]
+    identity: PublicKey,
+    #[cfg(not(feature = "coconut"))]
+    contract: Contract<Http>,
+    #[cfg(not(feature = "coconut"))]
+    eth_private_key: SecretKey,
+    #[cfg(not(feature = "coconut"))]
+    backup_bandwidth_token_keys_dir: std::path::PathBuf,
+}
+
+impl BandwidthController {
+    #[cfg(feature = "coconut")]
+    pub fn new(validator_endpoints: Vec<url::Url>, identity: PublicKey) -> Self {
+        BandwidthController {
+            validator_endpoints,
+            identity,
+        }
+    }
+
+    #[cfg(not(feature = "coconut"))]
+    pub fn new(
+        eth_endpoint: String,
+        eth_private_key: String,
+        backup_bandwidth_token_keys_dir: std::path::PathBuf,
+    ) -> Result<Self, GatewayClientError> {
+        // Fail early, on invalid url
+        let transport =
+            Http::new(&eth_endpoint).map_err(|_| GatewayClientError::InvalidURL(eth_endpoint))?;
+        let web3 = web3::Web3::new(transport);
+        // Fail early, on invalid abi
+        let contract = eth_contract(web3);
+        let eth_private_key = secp256k1::SecretKey::from_str(&eth_private_key)
+            .map_err(|_| GatewayClientError::InvalidEthereumPrivateKey)?;
+
+        Ok(BandwidthController {
+            contract,
+            eth_private_key,
+            backup_bandwidth_token_keys_dir,
+        })
+    }
+
+    #[cfg(not(feature = "coconut"))]
+    fn backup_keypair(&self, keypair: &identity::KeyPair) -> Result<(), GatewayClientError> {
+        std::fs::create_dir_all(&self.backup_bandwidth_token_keys_dir)?;
+        let file_path = self
+            .backup_bandwidth_token_keys_dir
+            .join(keypair.public_key().to_base58_string());
+        let mut file = std::fs::File::create(file_path)?;
+        file.write_all(&keypair.private_key().to_bytes())?;
+
+        Ok(())
+    }
+
+    #[cfg(feature = "coconut")]
+    pub async fn prepare_coconut_credential(
+        &self,
+    ) -> Result<coconut_interface::Credential, GatewayClientError> {
+        let verification_key = obtain_aggregate_verification_key(&self.validator_endpoints).await?;
+        let params = coconut_interface::Parameters::new(TOTAL_ATTRIBUTES).unwrap();
+
+        // TODO: Decide what is the value and additional info associated with the bandwidth voucher
+        let bandwidth_credential_attributes = BandwidthVoucherAttributes {
+            serial_number: params.random_scalar(),
+            binding_number: params.random_scalar(),
+            voucher_value: coconut_interface::hash_to_scalar(BANDWIDTH_VALUE.to_be_bytes()),
+            voucher_info: coconut_interface::hash_to_scalar(
+                String::from("BandwidthVoucher").as_bytes(),
+            ),
+        };
+
+        let bandwidth_credential = obtain_signature(
+            &params,
+            &bandwidth_credential_attributes,
+            &self.validator_endpoints,
+        )
+        .await?;
+        // the above would presumably be loaded from a file
+
+        // the below would only be executed once we know where we want to spend it (i.e. which gateway and stuff)
+        Ok(prepare_for_spending(
+            &self.identity.to_bytes(),
+            &bandwidth_credential,
+            &bandwidth_credential_attributes,
+            &verification_key,
+        )?)
+    }
+
+    #[cfg(not(feature = "coconut"))]
+    pub async fn prepare_token_credential(
+        &self,
+        gateway_identity: PublicKey,
+    ) -> Result<TokenCredential, GatewayClientError> {
+        let mut rng = OsRng;
+
+        let kp = identity::KeyPair::new(&mut rng);
+        self.backup_keypair(&kp)?;
+
+        let verification_key = *kp.public_key();
+        let signed_verification_key = kp.private_key().sign(&verification_key.to_bytes());
+        self.buy_token_credential(verification_key, signed_verification_key)
+            .await?;
+
+        let message: Vec<u8> = verification_key
+            .to_bytes()
+            .iter()
+            .chain(gateway_identity.to_bytes().iter())
+            .copied()
+            .collect();
+        let signature = kp.private_key().sign(&message);
+
+        Ok(TokenCredential::new(
+            verification_key,
+            gateway_identity,
+            BANDWIDTH_VALUE,
+            signature,
+        ))
+    }
+
+    #[cfg(not(feature = "coconut"))]
+    pub async fn buy_token_credential(
+        &self,
+        verification_key: PublicKey,
+        signed_verification_key: identity::Signature,
+    ) -> Result<(), GatewayClientError> {
+        // 0 means a transaction failure, 1 means success
+        let confirmations = if cfg!(debug_assertions) {
+            1
+        } else {
+            ETH_MIN_BLOCK_DEPTH
+        };
+        // 15 seconds per confirmation block + 10 seconds of network overhead
+        log::info!(
+            "Waiting for Ethereum transaction. This should take about {} seconds",
+            confirmations * 15 + 10
+        );
+        let recipt = self
+            .contract
+            .signed_call_with_confirmations(
+                ETH_BURN_FUNCTION_NAME,
+                (
+                    U256::from(TOKENS_TO_BURN),
+                    U256::from(&verification_key.to_bytes()),
+                    Bytes(signed_verification_key.to_bytes().to_vec()),
+                ),
+                Options::default(),
+                confirmations,
+                &self.eth_private_key,
+            )
+            .await?;
+        if Some(U64::from(0)) == recipt.status {
+            Err(GatewayClientError::BurnTokenError(
+                web3::Error::InvalidResponse(format!(
+                    "Transaction status is 0 (failure): {:?}",
+                    recipt.logs,
+                )),
+            ))
+        } else {
+            log::info!(
+                "Bought bandwidth on Ethereum: {} MB",
+                BANDWIDTH_VALUE / 1024 / 1024
+            );
+            Ok(())
+        }
+    }
+}
+
+#[cfg(not(feature = "coconut"))]
+#[cfg(test)]
+mod tests {
+    use network_defaults::ETH_EVENT_NAME;
+
+    use super::*;
+
+    #[test]
+    fn parse_contract() {
+        let transport =
+            Http::new("https://rinkeby.infura.io/v3/00000000000000000000000000000000").unwrap();
+        let web3 = web3::Web3::new(transport);
+        // test no panic occurs
+        eth_contract(web3);
+    }
+
+    #[test]
+    fn check_event_name_constant_against_abi() {
+        let transport =
+            Http::new("https://rinkeby.infura.io/v3/00000000000000000000000000000000").unwrap();
+        let web3 = web3::Web3::new(transport);
+        let contract = eth_contract(web3);
+        assert!(contract.abi().event(ETH_EVENT_NAME).is_ok());
+    }
+}

common/client-libs/gateway-client/src/client.rs

@@ -1,6 +1,7 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
+use crate::bandwidth::BandwidthController;
 use crate::cleanup_socket_message;
 use crate::error::GatewayClientError;
 use crate::packet_router::PacketRouter;
@@ -8,6 +9,10 @@ pub use crate::packet_router::{
     AcknowledgementReceiver, AcknowledgementSender, MixnetMessageReceiver, MixnetMessageSender,
 };
 use crate::socket_state::{PartiallyDelegated, SocketState};
+#[cfg(feature = "coconut")]
+use coconut_interface::Credential;
+#[cfg(not(feature = "coconut"))]
+use credentials::token::bandwidth::TokenCredential;
 use crypto::asymmetric::identity;
 use futures::{FutureExt, SinkExt, StreamExt};
 use gateway_requests::authentication::encrypted_address::EncryptedAddressBytes;
@@ -30,15 +35,11 @@ use fluvio_wasm_timer as wasm_timer;
 #[cfg(target_arch = "wasm32")]
 use wasm_utils::websocket::JSWebsocket;
 
-#[cfg(feature = "coconut")]
-use coconut_interface::Credential;
-
 const DEFAULT_RECONNECTION_ATTEMPTS: usize = 10;
 const DEFAULT_RECONNECTION_BACKOFF: Duration = Duration::from_secs(5);
 
 pub struct GatewayClient {
     authenticated: bool,
-    #[cfg(feature = "coconut")]
     bandwidth_remaining: i64,
     gateway_address: String,
     gateway_identity: identity::PublicKey,
@@ -47,6 +48,7 @@ pub struct GatewayClient {
     connection: SocketState,
     packet_router: PacketRouter,
     response_timeout_duration: Duration,
+    bandwidth_controller: Option<BandwidthController>,
 
     // reconnection related variables
     /// Specifies whether client should try to reconnect to gateway on connection failure.
@@ -69,20 +71,19 @@ impl GatewayClient {
         mixnet_message_sender: MixnetMessageSender,
         ack_sender: AcknowledgementSender,
         response_timeout_duration: Duration,
+        bandwidth_controller: Option<BandwidthController>,
     ) -> Self {
         GatewayClient {
             authenticated: false,
-
-            #[cfg(feature = "coconut")]
             bandwidth_remaining: 0,
             gateway_address,
-
             gateway_identity,
             local_identity,
             shared_key,
             connection: SocketState::NotConnected,
             packet_router: PacketRouter::new(ack_sender, mixnet_message_sender),
             response_timeout_duration,
+            bandwidth_controller,
             should_reconnect_on_failure: true,
             reconnection_attempts: DEFAULT_RECONNECTION_ATTEMPTS,
             reconnection_backoff: DEFAULT_RECONNECTION_BACKOFF,
@@ -118,10 +119,7 @@ impl GatewayClient {
 
         GatewayClient {
             authenticated: false,
-
-            #[cfg(feature = "coconut")]
             bandwidth_remaining: 0,
-
             gateway_address,
             gateway_identity,
             local_identity,
@@ -129,6 +127,7 @@ impl GatewayClient {
             connection: SocketState::NotConnected,
             packet_router,
             response_timeout_duration,
+            bandwidth_controller: None,
             should_reconnect_on_failure: false,
             reconnection_attempts: DEFAULT_RECONNECTION_ATTEMPTS,
             reconnection_backoff: DEFAULT_RECONNECTION_BACKOFF,
@@ -139,6 +138,10 @@ impl GatewayClient {
         self.gateway_identity
     }
 
+    pub fn remaining_bandwidth(&self) -> i64 {
+        self.bandwidth_remaining
+    }
+
     #[cfg(not(target_arch = "wasm32"))]
     async fn _close_connection(&mut self) -> Result<(), GatewayClientError> {
         match std::mem::replace(&mut self.connection, SocketState::NotConnected) {
@@ -203,14 +206,7 @@ impl GatewayClient {
 
         for i in 1..self.reconnection_attempts {
             info!("attempt {}...", i);
-            if self
-                .authenticate_and_start(
-                    #[cfg(feature = "coconut")]
-                    None,
-                )
-                .await
-                .is_ok()
-            {
+            if self.authenticate_and_start().await.is_ok() {
                 info!("managed to reconnect!");
                 return Ok(());
             }
@@ -229,13 +225,7 @@ impl GatewayClient {
 
         // final attempt (done separately to be able to return a proper error)
         info!("attempt {}", self.reconnection_attempts);
-        match self
-            .authenticate_and_start(
-                #[cfg(feature = "coconut")]
-                None,
-            )
-            .await
-        {
+        match self.authenticate_and_start().await {
             Ok(_) => {
                 info!("managed to reconnect!");
                 Ok(())
@@ -446,8 +436,12 @@ impl GatewayClient {
             ClientControlRequest::new_authenticate(self_address, encrypted_address, iv).into();
 
         match self.send_websocket_message(msg).await? {
-            ServerResponse::Authenticate { status } => {
+            ServerResponse::Authenticate {
+                status,
+                bandwidth_remaining,
+            } => {
                 self.authenticated = status;
+                self.bandwidth_remaining = bandwidth_remaining;
                 Ok(())
             }
             ServerResponse::Error { message } => Err(GatewayClientError::GatewayError(message)),
@@ -473,22 +467,15 @@ impl GatewayClient {
     }
 
     #[cfg(feature = "coconut")]
-    pub async fn claim_coconut_bandwidth(
+    async fn claim_coconut_bandwidth(
         &mut self,
-        coconut_credential: Credential,
+        credential: Credential,
     ) -> Result<(), GatewayClientError> {
-        if !self.authenticated {
-            return Err(GatewayClientError::NotAuthenticated);
-        }
-        if self.shared_key.is_none() {
-            return Err(GatewayClientError::NoSharedKeyAvailable);
-        }
-
         let mut rng = OsRng;
         let iv = IV::new_random(&mut rng);
 
         let msg = ClientControlRequest::new_enc_coconut_bandwidth_credential(
-            &coconut_credential,
+            &credential,
             self.shared_key.as_ref().unwrap(),
             iv,
         )
@@ -502,7 +489,64 @@ impl GatewayClient {
         Ok(())
     }
 
-    #[cfg(feature = "coconut")]
+    #[cfg(not(feature = "coconut"))]
+    async fn claim_token_bandwidth(
+        &mut self,
+        credential: TokenCredential,
+    ) -> Result<(), GatewayClientError> {
+        let mut rng = OsRng;
+
+        let iv = IV::new_random(&mut rng);
+
+        let msg = ClientControlRequest::new_enc_token_bandwidth_credential(
+            &credential,
+            self.shared_key.as_ref().unwrap(),
+            iv,
+        )
+        .into();
+        self.bandwidth_remaining = match self.send_websocket_message(msg).await? {
+            ServerResponse::Bandwidth { available_total } => Ok(available_total),
+            ServerResponse::Error { message } => Err(GatewayClientError::GatewayError(message)),
+            _ => Err(GatewayClientError::UnexpectedResponse),
+        }?;
+
+        Ok(())
+    }
+
+    pub async fn claim_bandwidth(&mut self) -> Result<(), GatewayClientError> {
+        if !self.authenticated {
+            return Err(GatewayClientError::NotAuthenticated);
+        }
+        if self.shared_key.is_none() {
+            return Err(GatewayClientError::NoSharedKeyAvailable);
+        }
+        if self.bandwidth_controller.is_none() {
+            return Err(GatewayClientError::NoBandwidthControllerAvailable);
+        }
+
+        warn!("Not enough bandwidth. Trying to get more bandwidth, this might take a while");
+
+        #[cfg(feature = "coconut")]
+        let credential = self
+            .bandwidth_controller
+            .as_ref()
+            .unwrap()
+            .prepare_coconut_credential()
+            .await?;
+        #[cfg(not(feature = "coconut"))]
+        let credential = self
+            .bandwidth_controller
+            .as_ref()
+            .unwrap()
+            .prepare_token_credential(self.gateway_identity)
+            .await?;
+
+        #[cfg(feature = "coconut")]
+        return self.claim_coconut_bandwidth(credential).await;
+        #[cfg(not(feature = "coconut"))]
+        return self.claim_token_bandwidth(credential).await;
+    }
+
     fn estimate_required_bandwidth(&self, packets: &[MixPacket]) -> i64 {
         packets
             .iter()
@@ -517,9 +561,16 @@ impl GatewayClient {
         if !self.authenticated {
             return Err(GatewayClientError::NotAuthenticated);
         }
-        #[cfg(feature = "coconut")]
-        if self.estimate_required_bandwidth(&packets) < self.bandwidth_remaining {
-            return Err(GatewayClientError::NotEnoughBandwidth);
+        if self.estimate_required_bandwidth(&packets) > self.bandwidth_remaining {
+            // Try to claim more bandwidth first, and return an error only if that is still not
+            // enough (the current granularity for bandwidth should be sufficient)
+            self.claim_bandwidth().await?;
+            if self.estimate_required_bandwidth(&packets) > self.bandwidth_remaining {
+                return Err(GatewayClientError::NotEnoughBandwidth(
+                    self.estimate_required_bandwidth(&packets),
+                    self.bandwidth_remaining,
+                ));
+            }
         }
         if !self.connection.is_established() {
             return Err(GatewayClientError::ConnectionNotEstablished);
@@ -585,9 +636,16 @@ impl GatewayClient {
         if !self.authenticated {
             return Err(GatewayClientError::NotAuthenticated);
         }
-        #[cfg(feature = "coconut")]
         if (mix_packet.sphinx_packet().len() as i64) > self.bandwidth_remaining {
-            return Err(GatewayClientError::NotEnoughBandwidth);
+            // Try to claim more bandwidth first, and return an error only if that is still not
+            // enough
+            self.claim_bandwidth().await?;
+            if (mix_packet.sphinx_packet().len() as i64) > self.bandwidth_remaining {
+                return Err(GatewayClientError::NotEnoughBandwidth(
+                    mix_packet.sphinx_packet().len() as i64,
+                    self.bandwidth_remaining,
+                ));
+            }
         }
         if !self.connection.is_established() {
             return Err(GatewayClientError::ConnectionNotEstablished);
@@ -624,10 +682,6 @@ impl GatewayClient {
         if !self.authenticated {
             return Err(GatewayClientError::NotAuthenticated);
         }
-        #[cfg(feature = "coconut")]
-        if self.bandwidth_remaining <= 0 {
-            return Err(GatewayClientError::NotEnoughBandwidth);
-        }
         if self.connection.is_partially_delegated() {
             return Ok(());
         }
@@ -655,22 +709,12 @@ impl GatewayClient {
         Ok(())
     }
 
-    pub async fn authenticate_and_start(
-        &mut self,
-        #[cfg(feature = "coconut")] coconut_credential: Option<Credential>,
-    ) -> Result<Arc<SharedKeys>, GatewayClientError> {
+    pub async fn authenticate_and_start(&mut self) -> Result<Arc<SharedKeys>, GatewayClientError> {
         if !self.connection.is_established() {
             self.establish_connection().await?;
         }
         let shared_key = self.perform_initial_authentication().await?;
 
-        #[cfg(feature = "coconut")]
-        {
-            if let Some(coconut_credential) = coconut_credential {
-                self.claim_coconut_bandwidth(coconut_credential).await?;
-            }
-        }
-
         // this call is NON-blocking
         self.start_listening_for_mixnet_messages()?;
 

common/client-libs/gateway-client/src/error.rs

@@ -2,39 +2,83 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use gateway_requests::registration::handshake::error::HandshakeError;
-use std::fmt::{self, Error, Formatter};
 use std::io;
+use thiserror::Error;
 use tungstenite::Error as WsError;
 #[cfg(target_arch = "wasm32")]
 use wasm_bindgen::JsValue;
+#[cfg(not(feature = "coconut"))]
+use web3::Error as Web3Error;
 
-#[derive(Debug)]
+#[derive(Debug, Error)]
 pub enum GatewayClientError {
+    #[error("Connection to the gateway is not established")]
     ConnectionNotEstablished,
+
+    #[error("Gateway returned an error response - {0}")]
     GatewayError(String),
-    NetworkError(WsError),
+
+    #[error("There was a network error - {0}")]
+    NetworkError(#[from] WsError),
 
     // TODO: see if `JsValue` is a reasonable type for this
     #[cfg(target_arch = "wasm32")]
+    #[error("There was a network error")]
     NetworkErrorWasm(JsValue),
 
-    NoSharedKeyAvailable,
-    ConnectionAbruptlyClosed,
-    MalformedResponse,
-    SerializeCredential,
-    NotAuthenticated,
-    NotEnoughBandwidth,
-    UnexpectedResponse,
-    ConnectionInInvalidState,
-    RegistrationFailure(HandshakeError),
-    AuthenticationFailure,
-    Timeout,
-}
+    #[cfg(not(feature = "coconut"))]
+    #[error("Could not backup keypair - {0}")]
+    IOError(#[from] std::io::Error),
 
-impl From<WsError> for GatewayClientError {
-    fn from(err: WsError) -> Self {
-        GatewayClientError::NetworkError(err)
-    }
+    #[cfg(not(feature = "coconut"))]
+    #[error("Could not burn ERC20 token in Ethereum smart contract - {0}")]
+    BurnTokenError(#[from] Web3Error),
+
+    #[cfg(not(feature = "coconut"))]
+    #[error("Invalid Ethereum private key")]
+    InvalidEthereumPrivateKey,
+
+    #[error("Invalid URL - {0}")]
+    InvalidURL(String),
+
+    #[error("No shared key was provided or obtained")]
+    NoSharedKeyAvailable,
+
+    #[error("No bandwidth controller provided")]
+    NoBandwidthControllerAvailable,
+
+    #[error("Credential error - {0}")]
+    CredentialError(#[from] credentials::error::Error),
+
+    #[error("Connection was abruptly closed")]
+    ConnectionAbruptlyClosed,
+
+    #[error("Received response was malformed")]
+    MalformedResponse,
+
+    #[error("Credential could not be serialized")]
+    SerializeCredential,
+
+    #[error("Client is not authenticated")]
+    NotAuthenticated,
+
+    #[error("Client does not have enough bandwidth: estimated {0}, remaining: {1}")]
+    NotEnoughBandwidth(i64, i64),
+
+    #[error("Received an unexpected response")]
+    UnexpectedResponse,
+
+    #[error("Connection is in an invalid state - please send a bug report")]
+    ConnectionInInvalidState,
+
+    #[error("Failed to finish registration handshake - {0}")]
+    RegistrationFailure(HandshakeError),
+
+    #[error("Authentication failure")]
+    AuthenticationFailure,
+
+    #[error("Timed out")]
+    Timeout,
 }
 
 impl GatewayClientError {
@@ -54,60 +98,3 @@ impl GatewayClientError {
         }
     }
 }
-
-#[cfg(target_arch = "wasm32")]
-impl From<JsValue> for GatewayClientError {
-    fn from(err: JsValue) -> Self {
-        GatewayClientError::NetworkErrorWasm(err)
-    }
-}
-
-// better human readable representation of the error, mostly so that GatewayClientError
-// would implement std::error::Error
-impl fmt::Display for GatewayClientError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
-        match self {
-            GatewayClientError::ConnectionNotEstablished => {
-                write!(f, "connection to the gateway is not established")
-            }
-            GatewayClientError::NoSharedKeyAvailable => {
-                write!(f, "no shared key was provided or obtained")
-            }
-            GatewayClientError::NotAuthenticated => write!(f, "client is not authenticated"),
-
-            GatewayClientError::NetworkError(err) => {
-                write!(f, "there was a network error - {}", err)
-            }
-            #[cfg(target_arch = "wasm32")]
-            GatewayClientError::NetworkErrorWasm(err) => {
-                write!(f, "there was a network error - {:?}", err)
-            }
-
-            GatewayClientError::ConnectionAbruptlyClosed => {
-                write!(f, "connection was abruptly closed")
-            }
-            GatewayClientError::Timeout => write!(f, "timed out"),
-            GatewayClientError::MalformedResponse => write!(f, "received response was malformed"),
-            GatewayClientError::ConnectionInInvalidState => write!(
-                f,
-                "connection is in an invalid state - please send a bug report"
-            ),
-            GatewayClientError::RegistrationFailure(handshake_err) => write!(
-                f,
-                "failed to finish registration handshake - {}",
-                handshake_err
-            ),
-            GatewayClientError::AuthenticationFailure => write!(f, "authentication failure"),
-            GatewayClientError::GatewayError(err) => {
-                write!(f, "gateway returned an error response - {}", err)
-            }
-            GatewayClientError::UnexpectedResponse => write!(f, "received an unexpected response"),
-            GatewayClientError::NotEnoughBandwidth => {
-                write!(f, "client does not have enough bandwidth")
-            }
-            GatewayClientError::SerializeCredential => {
-                write!(f, "credential could not be serialized")
-            }
-        }
-    }
-}

common/client-libs/gateway-client/src/lib.rs

@@ -8,6 +8,7 @@ pub use packet_router::{
 };
 use tungstenite::{protocol::Message, Error as WsError};
 
+pub mod bandwidth;
 pub mod client;
 pub mod error;
 pub mod packet_router;

common/client-libs/gateway-client/src/socket_state.rs

@@ -119,7 +119,7 @@ impl PartiallyDelegated {
             }
             .is_err()
             {
-                panic!("failed to send back `mixnet_receiver_future` result on the oneshot channel")
+                warn!("failed to send back `mixnet_receiver_future` result on the oneshot channel")
             }
         };
 
@@ -173,9 +173,9 @@ impl PartiallyDelegated {
         // this call failing is incredibly unlikely, but not impossible.
         // basically the gateway connection must have failed after executing previous line but
         // before starting execution of this one.
-        if notify.send(()).is_err() {
-            return Err(GatewayClientError::ConnectionAbruptlyClosed);
-        }
+        notify
+            .send(())
+            .map_err(|_| GatewayClientError::ConnectionAbruptlyClosed)?;
 
         let stream_results: Result<_, GatewayClientError> = stream_receiver
             .await

common/client-libs/validator-client/Cargo.toml

@@ -3,6 +3,7 @@ name = "validator-client"
 version = "0.1.0"
 authors = ["Jędrzej Stuczyński <andrew@nymtech.net>"]
 edition = "2018"
+rust-version = "1.56"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
@@ -25,13 +26,13 @@ network-defaults = { path = "../../network-defaults" }
 async-trait = { version = "0.1.51", optional = true }
 bip39 = { version = "1", features = ["rand"], optional = true }
 config = { path = "../../config", optional = true }
-cosmrs = { version = "0.1", features = ["rpc", "bip32", "cosmwasm"], optional = true }
-prost = { version = "0.7", default-features = false, optional = true }
+cosmrs = { version = "0.3", features = ["rpc", "bip32", "cosmwasm"], optional = true }
+prost = { version = "0.9", default-features = false, optional = true }
 flate2 = { version = "1.0.20", optional = true }
 sha2 = { version = "0.9.5", optional = true }
 itertools = { version = "0.10", optional = true }
 cosmwasm-std = { git = "https://github.com/jstuczyn/cosmwasm", branch="0.14.1-updatedk256", optional = true }
-ts-rs = "3.0"
+ts-rs = {version = "5.1", optional = true}
 
 [features]
 nymd-client = ["async-trait", "bip39", "config", "cosmrs", "prost", "flate2", "sha2", "itertools", "cosmwasm-std"]

common/client-libs/validator-client/src/client.rs

@@ -10,9 +10,9 @@ use mixnet_contract::StateParams;
 
 use crate::{validator_api, ValidatorClientError};
 use coconut_interface::{BlindSignRequestBody, BlindedSignatureResponse, VerificationKeyResponse};
+use mixnet_contract::{GatewayBond, MixNodeBond, MixnodeRewardingStatusResponse};
 #[cfg(feature = "nymd-client")]
-use mixnet_contract::RawDelegationData;
-use mixnet_contract::{GatewayBond, MixNodeBond};
+use mixnet_contract::{RawDelegationData, RewardingIntervalResponse};
 use url::Url;
 
 #[cfg(feature = "nymd-client")]
@@ -24,7 +24,6 @@ pub struct Config {
     mixnode_page_limit: Option<u32>,
     gateway_page_limit: Option<u32>,
     mixnode_delegations_page_limit: Option<u32>,
-    gateway_delegations_page_limit: Option<u32>,
 }
 
 #[cfg(feature = "nymd-client")]
@@ -41,7 +40,6 @@ impl Config {
             mixnode_page_limit: None,
             gateway_page_limit: None,
             mixnode_delegations_page_limit: None,
-            gateway_delegations_page_limit: None,
         }
     }
 
@@ -59,11 +57,6 @@ impl Config {
         self.mixnode_delegations_page_limit = limit;
         self
     }
-
-    pub fn with_gateway_delegations_page_limit(mut self, limit: Option<u32>) -> Config {
-        self.gateway_delegations_page_limit = limit;
-        self
-    }
 }
 
 #[cfg(feature = "nymd-client")]
@@ -74,7 +67,6 @@ pub struct Client<C> {
     mixnode_page_limit: Option<u32>,
     gateway_page_limit: Option<u32>,
     mixnode_delegations_page_limit: Option<u32>,
-    gateway_delegations_page_limit: Option<u32>,
 
     // ideally they would have been read-only, but unfortunately rust doesn't have such features
     pub validator_api: validator_api::Client,
@@ -100,7 +92,6 @@ impl Client<SigningNymdClient> {
             mixnode_page_limit: config.mixnode_page_limit,
             gateway_page_limit: config.gateway_page_limit,
             mixnode_delegations_page_limit: config.mixnode_delegations_page_limit,
-            gateway_delegations_page_limit: config.gateway_delegations_page_limit,
             validator_api: validator_api_client,
             nymd: nymd_client,
         })
@@ -136,7 +127,6 @@ impl Client<QueryNymdClient> {
             mixnode_page_limit: config.mixnode_page_limit,
             gateway_page_limit: config.gateway_page_limit,
             mixnode_delegations_page_limit: config.mixnode_delegations_page_limit,
-            gateway_delegations_page_limit: config.gateway_delegations_page_limit,
             validator_api: validator_api_client,
             nymd: nymd_client,
         })
@@ -182,6 +172,57 @@ impl<C> Client<C> {
         Ok(self.nymd.get_state_params().await?)
     }
 
+    pub async fn get_current_rewarding_interval(
+        &self,
+    ) -> Result<RewardingIntervalResponse, ValidatorClientError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        Ok(self.nymd.get_current_rewarding_interval().await?)
+    }
+
+    pub async fn get_rewarding_status(
+        &self,
+        mix_identity: mixnet_contract::IdentityKey,
+        rewarding_interval_nonce: u32,
+    ) -> Result<MixnodeRewardingStatusResponse, ValidatorClientError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        Ok(self
+            .nymd
+            .get_rewarding_status(mix_identity, rewarding_interval_nonce)
+            .await?)
+    }
+
+    pub async fn get_reward_pool(&self) -> Result<u128, ValidatorClientError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        Ok(self.nymd.get_reward_pool().await?.u128())
+    }
+
+    pub async fn get_circulating_supply(&self) -> Result<u128, ValidatorClientError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        Ok(self.nymd.get_circulating_supply().await?.u128())
+    }
+
+    pub async fn get_sybil_resistance_percent(&self) -> Result<u8, ValidatorClientError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        Ok(self.nymd.get_sybil_resistance_percent().await?)
+    }
+
+    pub async fn get_epoch_reward_percent(&self) -> Result<u8, ValidatorClientError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        Ok(self.nymd.get_epoch_reward_percent().await?)
+    }
+
     // basically handles paging for us
     pub async fn get_all_nymd_mixnodes(&self) -> Result<Vec<MixNodeBond>, ValidatorClientError>
     where
@@ -339,116 +380,6 @@ impl<C> Client<C> {
         Ok(delegations)
     }
 
-    pub async fn get_all_nymd_single_gateway_delegations(
-        &self,
-        identity: mixnet_contract::IdentityKey,
-    ) -> Result<Vec<mixnet_contract::Delegation>, ValidatorClientError>
-    where
-        C: CosmWasmClient + Sync,
-    {
-        let mut delegations = Vec::new();
-        let mut start_after = None;
-        loop {
-            let mut paged_response = self
-                .nymd
-                .get_gateway_delegations(
-                    identity.clone(),
-                    start_after.take(),
-                    self.gateway_delegations_page_limit,
-                )
-                .await?;
-            delegations.append(&mut paged_response.delegations);
-
-            if let Some(start_after_res) = paged_response.start_next_after {
-                start_after = Some(start_after_res)
-            } else {
-                break;
-            }
-        }
-
-        Ok(delegations)
-    }
-
-    pub async fn get_all_nymd_gateway_delegations(
-        &self,
-    ) -> Result<Vec<mixnet_contract::UnpackedDelegation<RawDelegationData>>, ValidatorClientError>
-    where
-        C: CosmWasmClient + Sync,
-    {
-        let mut delegations = Vec::new();
-        let mut start_after = None;
-        loop {
-            let mut paged_response = self
-                .nymd
-                .get_all_gateway_delegations(
-                    start_after.take(),
-                    self.gateway_delegations_page_limit,
-                )
-                .await?;
-            delegations.append(&mut paged_response.delegations);
-
-            if let Some(start_after_res) = paged_response.start_next_after {
-                start_after = Some(start_after_res)
-            } else {
-                break;
-            }
-        }
-
-        Ok(delegations)
-    }
-
-    pub async fn get_all_nymd_reverse_gateway_delegations(
-        &self,
-        delegation_owner: &cosmrs::AccountId,
-    ) -> Result<Vec<mixnet_contract::IdentityKey>, ValidatorClientError>
-    where
-        C: CosmWasmClient + Sync,
-    {
-        let mut delegations = Vec::new();
-        let mut start_after = None;
-        loop {
-            let mut paged_response = self
-                .nymd
-                .get_reverse_gateway_delegations_paged(
-                    mixnet_contract::Addr::unchecked(delegation_owner.as_ref()),
-                    start_after.take(),
-                    self.mixnode_delegations_page_limit,
-                )
-                .await?;
-            delegations.append(&mut paged_response.delegated_nodes);
-
-            if let Some(start_after_res) = paged_response.start_next_after {
-                start_after = Some(start_after_res)
-            } else {
-                break;
-            }
-        }
-
-        Ok(delegations)
-    }
-
-    pub async fn get_all_nymd_gateway_delegations_of_owner(
-        &self,
-        delegation_owner: &cosmrs::AccountId,
-    ) -> Result<Vec<mixnet_contract::Delegation>, ValidatorClientError>
-    where
-        C: CosmWasmClient + Sync,
-    {
-        let mut delegations = Vec::new();
-        for node_identity in self
-            .get_all_nymd_reverse_gateway_delegations(delegation_owner)
-            .await?
-        {
-            let delegation = self
-                .nymd
-                .get_gateway_delegation(node_identity, delegation_owner)
-                .await?;
-            delegations.push(delegation);
-        }
-
-        Ok(delegations)
-    }
-
     pub async fn blind_sign(
         &self,
         request_body: &BlindSignRequestBody,
@@ -488,12 +419,6 @@ impl ApiClient {
         Ok(self.validator_api.get_active_mixnodes().await?)
     }
 
-    pub async fn get_cached_active_gateways(
-        &self,
-    ) -> Result<Vec<GatewayBond>, ValidatorClientError> {
-        Ok(self.validator_api.get_active_gateways().await?)
-    }
-
     pub async fn get_cached_mixnodes(&self) -> Result<Vec<MixNodeBond>, ValidatorClientError> {
         Ok(self.validator_api.get_mixnodes().await?)
     }

common/client-libs/validator-client/src/nymd/cosmwasm_client/client.rs

@@ -22,7 +22,7 @@ use cosmrs::rpc::query::Query;
 use cosmrs::rpc::{self, HttpClient, Order};
 use cosmrs::tendermint::abci::Transaction;
 use cosmrs::tendermint::{abci, block, chain};
-use cosmrs::{AccountId, Coin, Denom};
+use cosmrs::{tx, AccountId, Coin, Denom};
 use prost::Message;
 use serde::{Deserialize, Serialize};
 use std::convert::{TryFrom, TryInto};
@@ -153,12 +153,9 @@ pub trait CosmWasmClient: rpc::Client {
             .map_err(|_| NymdError::SerializationError("Coins".to_owned()))
     }
 
-    // disabled until https://github.com/tendermint/tendermint/issues/6802
-    // and consequently https://github.com/informalsystems/tendermint-rs/issues/942 is resolved
-    //
-    // async fn get_tx(&self, id: tx::Hash) -> Result<TxResponse, NymdError> {
-    //     Ok(self.tx(id, false).await?)
-    // }
+    async fn get_tx(&self, id: tx::Hash) -> Result<TxResponse, NymdError> {
+        Ok(self.tx(id, false).await?)
+    }
 
     async fn search_tx(&self, query: Query) -> Result<Vec<TxResponse>, NymdError> {
         // according to https://docs.tendermint.com/master/rpc/#/Info/tx_search

common/client-libs/validator-client/src/nymd/cosmwasm_client/signing_client.rs

@@ -13,8 +13,8 @@ use cosmrs::distribution::MsgWithdrawDelegatorReward;
 use cosmrs::rpc::endpoint::broadcast;
 use cosmrs::rpc::{Error as TendermintRpcError, HttpClient, HttpClientUrl, SimpleRequest};
 use cosmrs::staking::{MsgDelegate, MsgUndelegate};
-use cosmrs::tx::{Fee, Msg, MsgType, SignDoc, SignerInfo};
-use cosmrs::{cosmwasm, rpc, tx, AccountId, Coin};
+use cosmrs::tx::{Fee, Msg, SignDoc, SignerInfo};
+use cosmrs::{cosmwasm, rpc, tx, AccountId, Any, Coin};
 use log::debug;
 use serde::Serialize;
 use sha2::Digest;
@@ -52,7 +52,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
                 .unwrap_or_default(),
             instantiate_permission: Default::default(),
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgStoreCode".to_owned()))?;
 
         let tx_res = self
@@ -114,7 +114,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
             init_msg: serde_json::to_vec(msg)?,
             funds: options.map(|options| options.funds).unwrap_or_default(),
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgInstantiateContract".to_owned()))?;
 
         let tx_res = self
@@ -154,7 +154,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
             new_admin: new_admin.clone(),
             contract: contract_address.clone(),
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgUpdateAdmin".to_owned()))?;
 
         let tx_res = self
@@ -179,7 +179,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
             sender: sender_address.clone(),
             contract: contract_address.clone(),
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgClearAdmin".to_owned()))?;
 
         let tx_res = self
@@ -211,7 +211,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
             code_id,
             migrate_msg: serde_json::to_vec(msg)?,
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgMigrateContract".to_owned()))?;
 
         let tx_res = self
@@ -243,7 +243,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
             msg: serde_json::to_vec(msg)?,
             funds,
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgExecuteContract".to_owned()))?;
 
         let tx_res = self
@@ -278,7 +278,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
                     msg: serde_json::to_vec(&msg)?,
                     funds,
                 }
-                .to_msg()
+                .to_any()
                 .map_err(|_| NymdError::SerializationError("MsgExecuteContract".to_owned()))
             })
             .collect::<Result<_, _>>()?;
@@ -312,7 +312,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
             to_address: recipient_address.clone(),
             amount,
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgSend".to_owned()))?;
 
         self.sign_and_broadcast_commit(sender_address, vec![send_msg], fee, memo)
@@ -332,7 +332,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
             validator_address: validator_address.to_owned(),
             amount,
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgDelegate".to_owned()))?;
 
         self.sign_and_broadcast_commit(delegator_address, vec![delegate_msg], fee, memo)
@@ -352,7 +352,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
             validator_address: validator_address.to_owned(),
             amount: Some(amount),
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgUndelegate".to_owned()))?;
 
         self.sign_and_broadcast_commit(delegator_address, vec![undelegate_msg], fee, memo)
@@ -370,7 +370,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
             delegator_address: delegator_address.to_owned(),
             validator_address: validator_address.to_owned(),
         }
-        .to_msg()
+        .to_any()
         .map_err(|_| NymdError::SerializationError("MsgWithdrawDelegatorReward".to_owned()))?;
 
         self.sign_and_broadcast_commit(delegator_address, vec![withdraw_msg], fee, memo)
@@ -381,7 +381,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
     async fn sign_and_broadcast_async(
         &self,
         signer_address: &AccountId,
-        messages: Vec<Msg>,
+        messages: Vec<Any>,
         fee: Fee,
         memo: impl Into<String> + Send + 'static,
     ) -> Result<broadcast::tx_async::Response, NymdError> {
@@ -397,7 +397,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
     async fn sign_and_broadcast_sync(
         &self,
         signer_address: &AccountId,
-        messages: Vec<Msg>,
+        messages: Vec<Any>,
         fee: Fee,
         memo: impl Into<String> + Send + 'static,
     ) -> Result<broadcast::tx_sync::Response, NymdError> {
@@ -413,7 +413,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
     async fn sign_and_broadcast_commit(
         &self,
         signer_address: &AccountId,
-        messages: Vec<Msg>,
+        messages: Vec<Any>,
         fee: Fee,
         memo: impl Into<String> + Send + 'static,
     ) -> Result<broadcast::tx_commit::Response, NymdError> {
@@ -428,7 +428,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
     fn sign_direct(
         &self,
         signer_address: &AccountId,
-        messages: Vec<Msg>,
+        messages: Vec<Any>,
         fee: Fee,
         memo: impl Into<String> + Send + 'static,
         signer_data: SignerData,
@@ -466,7 +466,7 @@ pub trait SigningCosmWasmClient: CosmWasmClient {
     async fn sign(
         &self,
         signer_address: &AccountId,
-        messages: Vec<Msg>,
+        messages: Vec<Any>,
         fee: Fee,
         memo: impl Into<String> + Send + 'static,
     ) -> Result<tx::Raw, NymdError> {
@@ -506,7 +506,7 @@ impl Client {
 
 #[async_trait]
 impl rpc::Client for Client {
-    async fn perform<R>(&self, request: R) -> rpc::Result<R::Response>
+    async fn perform<R>(&self, request: R) -> Result<R::Response, rpc::Error>
     where
         R: SimpleRequest,
     {

common/client-libs/validator-client/src/nymd/error.rs

@@ -7,7 +7,10 @@ use cosmrs::{bip32, tx, AccountId};
 use std::io;
 use thiserror::Error;
 
-pub use cosmrs::rpc::error::{Code, Error as TendermintRpcError};
+pub use cosmrs::rpc::error::{
+    Error as TendermintRpcError, ErrorDetail as TendermintRpcErrorDetail,
+};
+pub use cosmrs::rpc::response_error::{Code, ResponseError};
 
 #[derive(Debug, Error)]
 pub enum NymdError {
@@ -102,17 +105,21 @@ pub enum NymdError {
 }
 
 impl NymdError {
-    pub fn is_tendermint_timeout(&self) -> bool {
+    pub fn is_tendermint_response_timeout(&self) -> bool {
         match &self {
-            NymdError::TendermintError(tm_err) => {
-                if tm_err.code() == Code::InternalError {
+            NymdError::TendermintError(TendermintRpcError(
+                TendermintRpcErrorDetail::Response(err),
+                _,
+            )) => {
+                let response = &err.source;
+                if response.code() == Code::InternalError {
                     // 0.34 (and earlier) versions of tendermint seemed to be using phrase "timed out waiting ..."
                     // (https://github.com/tendermint/tendermint/blob/v0.34.13/rpc/core/mempool.go#L124)
                     // while 0.35+ has "timeout waiting for ..."
                     // https://github.com/tendermint/tendermint/blob/v0.35.0-rc3/internal/rpc/core/mempool.go#L99
                     // note that as of the time of writing this comment (08.10.2021), the most recent version
                     // of cosmos-sdk (v0.44.1) uses tendermint 0.34.13
-                    if let Some(data) = tm_err.data() {
+                    if let Some(data) = response.data() {
                         data.contains("timed out") || data.contains("timeout")
                     } else {
                         false
@@ -125,14 +132,18 @@ impl NymdError {
         }
     }
 
-    pub fn is_tendermint_duplicate(&self) -> bool {
+    pub fn is_tendermint_response_duplicate(&self) -> bool {
         match &self {
-            NymdError::TendermintError(tm_err) => {
-                if tm_err.code() == Code::InternalError {
+            NymdError::TendermintError(TendermintRpcError(
+                TendermintRpcErrorDetail::Response(err),
+                _,
+            )) => {
+                let response = &err.source;
+                if response.code() == Code::InternalError {
                     // this particular error message seems to be unchanged between 0.34 and newer versions
                     // https://github.com/tendermint/tendermint/blob/v0.34.13/mempool/errors.go#L10
                     // https://github.com/tendermint/tendermint/blob/v0.35.0-rc3/types/mempool.go#L10
-                    if let Some(data) = tm_err.data() {
+                    if let Some(data) = response.data() {
                         data.contains("tx already exists in cache")
                     } else {
                         false

common/client-libs/validator-client/src/nymd/fee_helpers.rs

@@ -6,9 +6,9 @@ use cosmrs::tx::{Fee, Gas};
 use cosmrs::Coin;
 use serde::{Deserialize, Serialize};
 use std::fmt;
-use ts_rs::TS;
 
-#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Serialize, Deserialize, TS)]
+#[cfg_attr(feature = "ts-rs", derive(ts_rs::TS))]
+#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Serialize, Deserialize)]
 pub enum Operation {
     Upload,
     Init,
@@ -23,10 +23,11 @@ pub enum Operation {
 
     BondGateway,
     UnbondGateway,
-    DelegateToGateway,
-    UndelegateFromGateway,
 
     UpdateStateParams,
+
+    BeginMixnodeRewarding,
+    FinishMixnodeRewarding,
 }
 
 pub(crate) fn calculate_fee(gas_price: &GasPrice, gas_limit: Gas) -> Coin {
@@ -43,13 +44,13 @@ impl fmt::Display for Operation {
             Operation::Send => f.write_str("Send"),
             Operation::BondMixnode => f.write_str("BondMixnode"),
             Operation::UnbondMixnode => f.write_str("UnbondMixnode"),
-            Operation::DelegateToMixnode => f.write_str("DelegateToMixnode"),
-            Operation::UndelegateFromMixnode => f.write_str("UndelegateFromMixnode"),
             Operation::BondGateway => f.write_str("BondGateway"),
             Operation::UnbondGateway => f.write_str("UnbondGateway"),
-            Operation::DelegateToGateway => f.write_str("DelegateToGateway"),
-            Operation::UndelegateFromGateway => f.write_str("UndelegateFromGateway"),
+            Operation::DelegateToMixnode => f.write_str("DelegateToMixnode"),
+            Operation::UndelegateFromMixnode => f.write_str("UndelegateFromMixnode"),
             Operation::UpdateStateParams => f.write_str("UpdateStateParams"),
+            Operation::BeginMixnodeRewarding => f.write_str("BeginMixnodeRewarding"),
+            Operation::FinishMixnodeRewarding => f.write_str("FinishMixnodeRewarding"),
         }
     }
 }
@@ -71,10 +72,10 @@ impl Operation {
 
             Operation::BondGateway => 175_000u64.into(),
             Operation::UnbondGateway => 175_000u64.into(),
-            Operation::DelegateToGateway => 175_000u64.into(),
-            Operation::UndelegateFromGateway => 175_000u64.into(),
 
             Operation::UpdateStateParams => 175_000u64.into(),
+            Operation::BeginMixnodeRewarding => 175_000u64.into(),
+            Operation::FinishMixnodeRewarding => 175_000u64.into(),
         }
     }
 

common/client-libs/validator-client/src/nymd/mod.rs

@@ -11,13 +11,13 @@ use crate::nymd::fee_helpers::Operation;
 use crate::nymd::wallet::DirectSecp256k1HdWallet;
 use cosmrs::rpc::endpoint::broadcast;
 use cosmrs::rpc::{Error as TendermintRpcError, HttpClientUrl};
-use cosmwasm_std::Coin;
+use cosmwasm_std::{Coin, Uint128};
 use mixnet_contract::{
     Addr, Delegation, ExecuteMsg, Gateway, GatewayOwnershipResponse, IdentityKey,
-    LayerDistribution, MixNode, MixOwnershipResponse, PagedAllDelegationsResponse,
-    PagedGatewayDelegationsResponse, PagedGatewayResponse, PagedMixDelegationsResponse,
-    PagedMixnodeResponse, PagedReverseGatewayDelegationsResponse,
-    PagedReverseMixDelegationsResponse, QueryMsg, RawDelegationData, StateParams,
+    LayerDistribution, MixNode, MixOwnershipResponse, MixnodeRewardingStatusResponse,
+    PagedAllDelegationsResponse, PagedGatewayResponse, PagedMixDelegationsResponse,
+    PagedMixnodeResponse, PagedReverseMixDelegationsResponse, QueryMsg, RawDelegationData,
+    RewardingIntervalResponse, StateParams,
 };
 use serde::Serialize;
 use std::collections::HashMap;
@@ -28,10 +28,11 @@ pub use crate::nymd::cosmwasm_client::signing_client::SigningCosmWasmClient;
 pub use crate::nymd::gas_price::GasPrice;
 pub use cosmrs::rpc::HttpClient as QueryNymdClient;
 pub use cosmrs::tendermint::block::Height;
+pub use cosmrs::tendermint::hash;
 pub use cosmrs::tendermint::Time as TendermintTime;
 pub use cosmrs::tx::{Fee, Gas};
 pub use cosmrs::Coin as CosmosCoin;
-pub use cosmrs::{AccountId, Denom};
+pub use cosmrs::{AccountId, Decimal, Denom};
 pub use signing_client::Client as SigningNymdClient;
 
 pub mod cosmwasm_client;
@@ -185,6 +186,21 @@ impl<C> NymdClient<C> {
         self.client.get_height().await
     }
 
+    /// Obtains the hash of a block specified by the provided height.
+    ///
+    /// # Arguments
+    ///
+    /// * `height`: height of the block for which we want to obtain the hash.
+    pub async fn get_block_hash(&self, height: u32) -> Result<hash::Hash, NymdError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        self.client
+            .get_block(Some(height))
+            .await
+            .map(|block| block.block_id.hash)
+    }
+
     pub async fn get_balance(&self, address: &AccountId) -> Result<Option<CosmosCoin>, NymdError>
     where
         C: CosmWasmClient + Sync,
@@ -202,6 +218,35 @@ impl<C> NymdClient<C> {
             .await
     }
 
+    pub async fn get_current_rewarding_interval(
+        &self,
+    ) -> Result<RewardingIntervalResponse, NymdError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        let request = QueryMsg::CurrentRewardingInterval {};
+        self.client
+            .query_contract_smart(self.contract_address()?, &request)
+            .await
+    }
+
+    pub async fn get_rewarding_status(
+        &self,
+        mix_identity: mixnet_contract::IdentityKey,
+        rewarding_interval_nonce: u32,
+    ) -> Result<MixnodeRewardingStatusResponse, NymdError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        let request = QueryMsg::GetRewardingStatus {
+            mix_identity,
+            rewarding_interval_nonce,
+        };
+        self.client
+            .query_contract_smart(self.contract_address()?, &request)
+            .await
+    }
+
     pub async fn get_layer_distribution(&self) -> Result<LayerDistribution, NymdError>
     where
         C: CosmWasmClient + Sync,
@@ -212,6 +257,46 @@ impl<C> NymdClient<C> {
             .await
     }
 
+    pub async fn get_reward_pool(&self) -> Result<Uint128, NymdError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        let request = QueryMsg::GetRewardPool {};
+        self.client
+            .query_contract_smart(self.contract_address()?, &request)
+            .await
+    }
+
+    pub async fn get_circulating_supply(&self) -> Result<Uint128, NymdError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        let request = QueryMsg::GetCirculatingSupply {};
+        self.client
+            .query_contract_smart(self.contract_address()?, &request)
+            .await
+    }
+
+    pub async fn get_sybil_resistance_percent(&self) -> Result<u8, NymdError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        let request = QueryMsg::GetSybilResistancePercent {};
+        self.client
+            .query_contract_smart(self.contract_address()?, &request)
+            .await
+    }
+
+    pub async fn get_epoch_reward_percent(&self) -> Result<u8, NymdError>
+    where
+        C: CosmWasmClient + Sync,
+    {
+        let request = QueryMsg::GetEpochRewardPercent {};
+        self.client
+            .query_contract_smart(self.contract_address()?, &request)
+            .await
+    }
+
     /// Checks whether there is a bonded mixnode associated with the provided client's address
     pub async fn owns_mixnode(&self, address: &AccountId) -> Result<bool, NymdError>
     where
@@ -354,82 +439,6 @@ impl<C> NymdClient<C> {
             .await
     }
 
-    /// Gets list of all delegations towards particular gateway on particular page.
-    pub async fn get_gateway_delegations(
-        &self,
-        gateway_identity: IdentityKey,
-        start_after: Option<Addr>,
-        page_limit: Option<u32>,
-    ) -> Result<PagedGatewayDelegationsResponse, NymdError>
-    where
-        C: CosmWasmClient + Sync,
-    {
-        let request = QueryMsg::GetGatewayDelegations {
-            gateway_identity,
-            start_after,
-            limit: page_limit,
-        };
-        self.client
-            .query_contract_smart(self.contract_address()?, &request)
-            .await
-    }
-
-    /// Gets list of all gateway delegations on particular page.
-    pub async fn get_all_gateway_delegations(
-        &self,
-        start_after: Option<Vec<u8>>,
-        page_limit: Option<u32>,
-    ) -> Result<PagedAllDelegationsResponse<RawDelegationData>, NymdError>
-    where
-        C: CosmWasmClient + Sync,
-    {
-        let request = QueryMsg::GetAllGatewayDelegations {
-            start_after,
-            limit: page_limit,
-        };
-        self.client
-            .query_contract_smart(self.contract_address()?, &request)
-            .await
-    }
-
-    /// Gets list of all the gateways on which a particular address delegated.
-    pub async fn get_reverse_gateway_delegations_paged(
-        &self,
-        delegation_owner: Addr,
-        start_after: Option<IdentityKey>,
-        page_limit: Option<u32>,
-    ) -> Result<PagedReverseGatewayDelegationsResponse, NymdError>
-    where
-        C: CosmWasmClient + Sync,
-    {
-        let request = QueryMsg::GetReverseGatewayDelegations {
-            delegation_owner,
-            start_after,
-            limit: page_limit,
-        };
-        self.client
-            .query_contract_smart(self.contract_address()?, &request)
-            .await
-    }
-
-    /// Checks value of delegation of given client towards particular gateway.
-    pub async fn get_gateway_delegation(
-        &self,
-        gateway_identity: IdentityKey,
-        delegator: &AccountId,
-    ) -> Result<Delegation, NymdError>
-    where
-        C: CosmWasmClient + Sync,
-    {
-        let request = QueryMsg::GetGatewayDelegation {
-            gateway_identity,
-            address: Addr::unchecked(delegator.as_ref()),
-        };
-        self.client
-            .query_contract_smart(self.contract_address()?, &request)
-            .await
-    }
-
     /// Send funds from one address to another
     pub async fn send(
         &self,
@@ -698,57 +707,6 @@ impl<C> NymdClient<C> {
             .await
     }
 
-    /// Delegates specified amount of stake to particular gateway.
-    pub async fn delegate_to_gateway(
-        &self,
-        gateway_identity: &str,
-        amount: &Coin,
-    ) -> Result<ExecuteResult, NymdError>
-    where
-        C: SigningCosmWasmClient + Sync,
-    {
-        let fee = self.get_fee(Operation::DelegateToGateway);
-
-        let req = ExecuteMsg::DelegateToGateway {
-            gateway_identity: gateway_identity.to_string(),
-        };
-        self.client
-            .execute(
-                self.address(),
-                self.contract_address()?,
-                &req,
-                fee,
-                "Delegating to gateway from rust!",
-                vec![cosmwasm_coin_ptr_to_cosmos_coin(amount)],
-            )
-            .await
-    }
-
-    /// Removes stake delegation from a particular gateway.
-    pub async fn remove_gateway_delegation(
-        &self,
-        gateway_identity: &str,
-    ) -> Result<ExecuteResult, NymdError>
-    where
-        C: SigningCosmWasmClient + Sync,
-    {
-        let fee = self.get_fee(Operation::UndelegateFromGateway);
-
-        let req = ExecuteMsg::UndelegateFromGateway {
-            gateway_identity: gateway_identity.to_string(),
-        };
-        self.client
-            .execute(
-                self.address(),
-                self.contract_address()?,
-                &req,
-                fee,
-                "Removing gateway delegation from rust!",
-                Vec::new(),
-            )
-            .await
-    }
-
     pub async fn update_state_params(
         &self,
         new_params: StateParams,
@@ -770,6 +728,54 @@ impl<C> NymdClient<C> {
             )
             .await
     }
+
+    pub async fn begin_mixnode_rewarding(
+        &self,
+        rewarding_interval_nonce: u32,
+    ) -> Result<ExecuteResult, NymdError>
+    where
+        C: SigningCosmWasmClient + Sync,
+    {
+        let fee = self.get_fee(Operation::BeginMixnodeRewarding);
+
+        let req = ExecuteMsg::BeginMixnodeRewarding {
+            rewarding_interval_nonce,
+        };
+        self.client
+            .execute(
+                self.address(),
+                self.contract_address()?,
+                &req,
+                fee,
+                "Beginning mixnode rewarding procedure",
+                Vec::new(),
+            )
+            .await
+    }
+
+    pub async fn finish_mixnode_rewarding(
+        &self,
+        rewarding_interval_nonce: u32,
+    ) -> Result<ExecuteResult, NymdError>
+    where
+        C: SigningCosmWasmClient + Sync,
+    {
+        let fee = self.get_fee(Operation::FinishMixnodeRewarding);
+
+        let req = ExecuteMsg::FinishMixnodeRewarding {
+            rewarding_interval_nonce,
+        };
+        self.client
+            .execute(
+                self.address(),
+                self.contract_address()?,
+                &req,
+                fee,
+                "Finishing mixnode rewarding procedure",
+                Vec::new(),
+            )
+            .await
+    }
 }
 
 fn cosmwasm_coin_to_cosmos_coin(coin: Coin) -> CosmosCoin {

common/client-libs/validator-client/src/validator_api/mod.rs

@@ -73,11 +73,6 @@ impl Client {
             .await
     }
 
-    pub async fn get_active_gateways(&self) -> Result<Vec<GatewayBond>, ValidatorAPIError> {
-        self.query_validator_api(&[routes::API_VERSION, routes::GATEWAYS, routes::ACTIVE])
-            .await
-    }
-
     pub async fn blind_sign(
         &self,
         request_body: &BlindSignRequestBody,

common/coconut-interface/Cargo.toml

@@ -8,4 +8,4 @@ description = "Crutch library until there is proper SerDe support for coconut st
 serde = { version = "1.0", features = ["derive"] }
 getset = "0.1.1"
 
-coconut-rs = { git = "https://github.com/nymtech/coconut.git", branch = "0.5.0" }
+nymcoconut = {path = "../nymcoconut" }

common/coconut-interface/src/lib.rs

@@ -4,7 +4,7 @@
 use getset::{CopyGetters, Getters};
 use serde::{Deserialize, Serialize};
 
-pub use coconut_rs::*;
+pub use nymcoconut::*;
 
 #[derive(Serialize, Deserialize, Getters, CopyGetters, Clone)]
 pub struct Credential {
@@ -42,7 +42,7 @@ impl Credential {
             .iter()
             .map(hash_to_scalar)
             .collect::<Vec<Attribute>>();
-        coconut_rs::verify_credential(&params, verification_key, &self.theta, &public_attributes)
+        nymcoconut::verify_credential(&params, verification_key, &self.theta, &public_attributes)
     }
 }
 
@@ -84,7 +84,7 @@ pub struct BlindSignRequestBody {
     #[getset(get = "pub")]
     blind_sign_request: BlindSignRequest,
     #[getset(get = "pub")]
-    public_key: coconut_rs::PublicKey,
+    public_key: nymcoconut::PublicKey,
     public_attributes: Vec<String>,
     #[getset(get = "pub")]
     total_params: u32,
@@ -92,13 +92,13 @@ pub struct BlindSignRequestBody {
 
 impl BlindSignRequestBody {
     pub fn new(
-        blind_sign_request: BlindSignRequest,
-        public_key: &coconut_rs::PublicKey,
+        blind_sign_request: &BlindSignRequest,
+        public_key: &nymcoconut::PublicKey,
         public_attributes: &[Attribute],
         total_params: u32,
     ) -> BlindSignRequestBody {
         BlindSignRequestBody {
-            blind_sign_request,
+            blind_sign_request: blind_sign_request.clone(),
             public_key: public_key.clone(),
             public_attributes: public_attributes
                 .iter()

common/credentials/Cargo.toml

@@ -11,4 +11,6 @@ url = "2.2"
 
 # I guess temporarily until we get serde support in coconut up and running
 coconut-interface = { path = "../coconut-interface" }
+crypto = { path = "../crypto" }
+network-defaults = { path = "../network-defaults" }
 validator-client = { path = "../client-libs/validator-client" }

common/credentials/src/bandwidth.rs

@@ -1,48 +0,0 @@
-// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
-// SPDX-License-Identifier: Apache-2.0
-
-// for time being assume the bandwidth credential consists of public identity of the requester
-// and private (though known... just go along with it) infinite bandwidth value
-// right now this has no double-spending protection, spender binding, etc
-// it's the simplest possible case
-
-use url::Url;
-
-use crate::error::Error;
-use crate::utils::{obtain_aggregate_signature, prepare_credential_for_spending};
-use coconut_interface::{hash_to_scalar, Credential, Parameters, Signature, VerificationKey};
-
-const BANDWIDTH_VALUE: u64 = 10 * 1024 * 1024 * 1024; // 10 GB
-
-pub const PUBLIC_ATTRIBUTES: u32 = 1;
-pub const PRIVATE_ATTRIBUTES: u32 = 1;
-pub const TOTAL_ATTRIBUTES: u32 = PUBLIC_ATTRIBUTES + PRIVATE_ATTRIBUTES;
-
-// TODO: this definitely has to be moved somewhere else. It's just a temporary solution
-pub async fn obtain_signature(raw_identity: &[u8], validators: &[Url]) -> Result<Signature, Error> {
-    let public_attributes = vec![hash_to_scalar(BANDWIDTH_VALUE.to_be_bytes())];
-    let private_attributes = vec![hash_to_scalar(raw_identity)];
-
-    let params = Parameters::new(TOTAL_ATTRIBUTES)?;
-
-    obtain_aggregate_signature(&params, &public_attributes, &private_attributes, validators).await
-}
-
-pub fn prepare_for_spending(
-    raw_identity: &[u8],
-    signature: &Signature,
-    verification_key: &VerificationKey,
-) -> Result<Credential, Error> {
-    let public_attributes = vec![BANDWIDTH_VALUE.to_be_bytes().to_vec()];
-    let private_attributes = vec![raw_identity.to_vec()];
-
-    let params = Parameters::new(TOTAL_ATTRIBUTES)?;
-
-    prepare_credential_for_spending(
-        &params,
-        public_attributes,
-        private_attributes,
-        signature,
-        verification_key,
-    )
-}

common/credentials/src/coconut/bandwidth.rs

@@ -0,0 +1,77 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+// for time being assume the bandwidth credential consists of public identity of the requester
+// and private (though known... just go along with it) infinite bandwidth value
+// right now this has no double-spending protection, spender binding, etc
+// it's the simplest possible case
+
+use coconut_interface::{
+    Credential, Parameters, PrivateAttribute, PublicAttribute, Signature, VerificationKey,
+};
+use network_defaults::BANDWIDTH_VALUE;
+use url::Url;
+
+use crate::error::Error;
+
+use super::utils::{obtain_aggregate_signature, prepare_credential_for_spending};
+
+pub const PUBLIC_ATTRIBUTES: u32 = 2;
+pub const PRIVATE_ATTRIBUTES: u32 = 2;
+pub const TOTAL_ATTRIBUTES: u32 = PUBLIC_ATTRIBUTES + PRIVATE_ATTRIBUTES;
+
+pub struct BandwidthVoucherAttributes {
+    // a random secret value generated by the client used for double-spending detection
+    pub serial_number: PrivateAttribute,
+    // a random secret value generated by the client used to bind multiple credentials together
+    pub binding_number: PrivateAttribute,
+    // the value (e.g., bandwidth) encoded in this voucher
+    pub voucher_value: PublicAttribute,
+    // a field with public information, e.g., type of voucher, epoch etc.
+    pub voucher_info: PublicAttribute,
+}
+
+impl BandwidthVoucherAttributes {
+    pub fn get_public_attributes(&self) -> Vec<PublicAttribute> {
+        vec![self.voucher_value, self.voucher_info]
+    }
+
+    pub fn get_private_attributes(&self) -> Vec<PrivateAttribute> {
+        vec![self.serial_number, self.binding_number]
+    }
+}
+
+// TODO: this definitely has to be moved somewhere else. It's just a temporary solution
+pub async fn obtain_signature(
+    params: &Parameters,
+    attributes: &BandwidthVoucherAttributes,
+    validators: &[Url],
+) -> Result<Signature, Error> {
+    let public_attributes = attributes.get_public_attributes();
+    let private_attributes = attributes.get_private_attributes();
+
+    obtain_aggregate_signature(params, &public_attributes, &private_attributes, validators).await
+}
+
+pub fn prepare_for_spending(
+    raw_identity: &[u8],
+    signature: &Signature,
+    attributes: &BandwidthVoucherAttributes,
+    verification_key: &VerificationKey,
+) -> Result<Credential, Error> {
+    let public_attributes = vec![
+        raw_identity.to_vec(),
+        BANDWIDTH_VALUE.to_be_bytes().to_vec(),
+    ];
+
+    let params = Parameters::new(TOTAL_ATTRIBUTES)?;
+
+    prepare_credential_for_spending(
+        &params,
+        public_attributes,
+        attributes.serial_number,
+        attributes.binding_number,
+        signature,
+        verification_key,
+    )
+}

common/credentials/src/coconut/mod.rs

@@ -0,0 +1,5 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+pub mod bandwidth;
+pub mod utils;

common/credentials/src/coconut/utils.rs

@@ -1,14 +1,16 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
-use crate::error::Error;
 use coconut_interface::{
-    aggregate_signature_shares, aggregate_verification_keys, hash_to_scalar, prepare_blind_sign,
-    prove_credential, Attribute, BlindSignRequestBody, Credential, Parameters, Signature,
+    aggregate_signature_shares, aggregate_verification_keys, prepare_blind_sign,
+    prove_bandwidth_credential, Attribute, BlindSignRequestBody, Credential, Parameters, Signature,
     SignatureShare, VerificationKey,
 };
 use url::Url;
 
+use crate::coconut::bandwidth::PRIVATE_ATTRIBUTES;
+use crate::error::Error;
+
 /// Contacts all provided validators and then aggregate their verification keys.
 ///
 /// # Arguments
@@ -63,17 +65,18 @@ async fn obtain_partial_credential(
     public_attributes: &[Attribute],
     private_attributes: &[Attribute],
     client: &validator_client::ApiClient,
+    validator_vk: &VerificationKey,
 ) -> Result<Signature, Error> {
     let elgamal_keypair = coconut_interface::elgamal_keygen(params);
     let blind_sign_request = prepare_blind_sign(
         params,
-        elgamal_keypair.public_key(),
+        &elgamal_keypair,
         private_attributes,
         public_attributes,
     )?;
 
     let blind_sign_request_body = BlindSignRequestBody::new(
-        blind_sign_request,
+        &blind_sign_request,
         elgamal_keypair.public_key(),
         public_attributes,
         (public_attributes.len() + private_attributes.len()) as u32,
@@ -83,7 +86,17 @@ async fn obtain_partial_credential(
         .blind_sign(&blind_sign_request_body)
         .await?
         .blinded_signature;
-    Ok(blinded_signature.unblind(elgamal_keypair.private_key()))
+
+    let unblinded_signature = blinded_signature.unblind(
+        params,
+        elgamal_keypair.private_key(),
+        validator_vk,
+        private_attributes,
+        public_attributes,
+        &blind_sign_request.get_commitment_hash(),
+    )?;
+
+    Ok(unblinded_signature)
 }
 
 pub async fn obtain_aggregate_signature(
@@ -97,40 +110,76 @@ pub async fn obtain_aggregate_signature(
     }
 
     let mut shares = Vec::with_capacity(validators.len());
+    let mut validators_partial_vks: Vec<VerificationKey> = Vec::with_capacity(validators.len());
 
     let mut client = validator_client::ApiClient::new(validators[0].clone());
-    let first =
-        obtain_partial_credential(params, public_attributes, private_attributes, &client).await?;
+    let validator_partial_vk = client.get_coconut_verification_key().await?;
+    validators_partial_vks.push(validator_partial_vk.key.clone());
+
+    let first = obtain_partial_credential(
+        params,
+        public_attributes,
+        private_attributes,
+        &client,
+        &validator_partial_vk.key,
+    )
+    .await?;
     shares.push(SignatureShare::new(first, 0));
 
     for (id, validator_url) in validators.iter().enumerate().skip(1) {
         client.change_validator_api(validator_url.clone());
-        let signature =
-            obtain_partial_credential(params, public_attributes, private_attributes, &client)
-                .await?;
+        let validator_partial_vk = client.get_coconut_verification_key().await?;
+        validators_partial_vks.push(validator_partial_vk.key.clone());
+        let signature = obtain_partial_credential(
+            params,
+            public_attributes,
+            private_attributes,
+            &client,
+            &validator_partial_vk.key,
+        )
+        .await?;
         let share = SignatureShare::new(signature, id as u64);
         shares.push(share)
     }
 
-    Ok(aggregate_signature_shares(&shares)?)
+    let mut attributes = Vec::with_capacity(private_attributes.len() + public_attributes.len());
+    attributes.extend_from_slice(private_attributes);
+    attributes.extend_from_slice(public_attributes);
+
+    let mut indices: Vec<u64> = Vec::with_capacity(validators_partial_vks.len());
+    for i in 1..validators_partial_vks.len() {
+        indices.push(i as u64);
+    }
+    let verification_key =
+        aggregate_verification_keys(&validators_partial_vks, Some(indices.as_ref()))?;
+
+    Ok(aggregate_signature_shares(
+        params,
+        &verification_key,
+        &attributes,
+        &shares,
+    )?)
 }
 
 // TODO: better type flow
 pub fn prepare_credential_for_spending(
     params: &Parameters,
     public_attributes: Vec<Vec<u8>>,
-    private_attributes: Vec<Vec<u8>>,
+    serial_number: Attribute,
+    binding_number: Attribute,
     signature: &Signature,
     verification_key: &VerificationKey,
 ) -> Result<Credential, Error> {
-    let private_attributes = private_attributes
-        .iter()
-        .map(hash_to_scalar)
-        .collect::<Vec<Attribute>>();
-    let theta = prove_credential(params, verification_key, signature, &private_attributes)?;
+    let theta = prove_bandwidth_credential(
+        params,
+        verification_key,
+        signature,
+        serial_number,
+        binding_number,
+    )?;
 
     Ok(Credential::new(
-        (public_attributes.len() + private_attributes.len()) as u32,
+        (public_attributes.len() + PRIVATE_ATTRIBUTES as usize) as u32,
         theta,
         public_attributes,
         signature,

common/credentials/src/lib.rs

@@ -1,8 +1,8 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
-pub mod bandwidth;
+pub mod coconut;
 pub mod error;
-mod utils;
+pub mod token;
 
-pub use utils::{obtain_aggregate_signature, obtain_aggregate_verification_key};
+pub use coconut::utils::{obtain_aggregate_signature, obtain_aggregate_verification_key};

common/credentials/src/token/bandwidth.rs

@@ -0,0 +1,140 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use crypto::asymmetric::identity::{PublicKey, Signature, PUBLIC_KEY_LENGTH, SIGNATURE_LENGTH};
+
+use crate::error::Error;
+use std::convert::TryInto;
+
+#[cfg(not(feature = "coconut"))]
+pub struct TokenCredential {
+    verification_key: PublicKey,
+    gateway_identity: PublicKey,
+    bandwidth: u64,
+    signature: Signature,
+}
+
+#[cfg(not(feature = "coconut"))]
+impl TokenCredential {
+    pub fn new(
+        verification_key: PublicKey,
+        gateway_identity: PublicKey,
+        bandwidth: u64,
+        signature: Signature,
+    ) -> Self {
+        TokenCredential {
+            verification_key,
+            gateway_identity,
+            bandwidth,
+            signature,
+        }
+    }
+
+    pub fn verification_key(&self) -> PublicKey {
+        self.verification_key
+    }
+
+    pub fn gateway_identity(&self) -> PublicKey {
+        self.gateway_identity
+    }
+
+    pub fn bandwidth(&self) -> u64 {
+        self.bandwidth
+    }
+
+    pub fn signature_bytes(&self) -> [u8; 64] {
+        self.signature.to_bytes()
+    }
+
+    pub fn verify_signature(&self) -> bool {
+        let message: Vec<u8> = self
+            .verification_key
+            .to_bytes()
+            .iter()
+            .chain(self.gateway_identity.to_bytes().iter())
+            .copied()
+            .collect();
+        self.verification_key
+            .verify(&message, &self.signature)
+            .is_ok()
+    }
+
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.verification_key
+            .to_bytes()
+            .iter()
+            .chain(self.gateway_identity.to_bytes().iter())
+            .chain(self.bandwidth.to_be_bytes().iter())
+            .chain(self.signature.to_bytes().iter())
+            .copied()
+            .collect()
+    }
+
+    pub fn from_bytes(b: &[u8]) -> Result<Self, Error> {
+        if b.len() != 2 * PUBLIC_KEY_LENGTH + 8 + SIGNATURE_LENGTH {
+            return Err(Error::BandwidthCredentialError);
+        }
+        let verification_key = PublicKey::from_bytes(&b[..PUBLIC_KEY_LENGTH])
+            .map_err(|_| Error::BandwidthCredentialError)?;
+        let gateway_identity = PublicKey::from_bytes(&b[PUBLIC_KEY_LENGTH..2 * PUBLIC_KEY_LENGTH])
+            .map_err(|_| Error::BandwidthCredentialError)?;
+        let bandwidth = u64::from_be_bytes(
+            b[2 * PUBLIC_KEY_LENGTH..2 * PUBLIC_KEY_LENGTH + 8]
+                .try_into()
+                // unwrapping is safe because we know we have 8 bytes
+                .unwrap(),
+        );
+        let signature = Signature::from_bytes(&b[2 * PUBLIC_KEY_LENGTH + 8..])
+            .map_err(|_| Error::BandwidthCredentialError)?;
+        Ok(TokenCredential {
+            verification_key,
+            gateway_identity,
+            bandwidth,
+            signature,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[cfg(not(feature = "coconut"))]
+    #[test]
+    fn token_serde() {
+        // pre-generated, valid values
+        let verification_key = PublicKey::from_bytes(&[
+            103, 105, 71, 177, 149, 245, 26, 32, 73, 121, 76, 50, 94, 88, 119, 231, 91, 229, 167,
+            56, 39, 62, 185, 39, 83, 246, 153, 27, 17, 155, 109, 73,
+        ])
+        .unwrap();
+        let gateway_identity = PublicKey::from_bytes(&[
+            37, 113, 137, 189, 157, 82, 35, 2, 187, 136, 61, 119, 98, 5, 245, 82, 46, 124, 67, 45,
+            165, 255, 53, 222, 185, 252, 6, 148, 128, 15, 206, 19,
+        ])
+        .unwrap();
+        let signature = Signature::from_bytes(&[
+            117, 251, 162, 217, 57, 2, 50, 210, 206, 81, 236, 90, 74, 201, 69, 237, 240, 247, 214,
+            158, 220, 89, 235, 222, 85, 134, 73, 73, 8, 60, 25, 39, 183, 28, 83, 193, 31, 174, 25,
+            24, 38, 215, 205, 228, 159, 135, 35, 4, 171, 59, 100, 157, 12, 249, 77, 52, 143, 4, 32,
+            28, 147, 70, 182, 14,
+        ])
+        .unwrap();
+        let credential = TokenCredential::new(verification_key, gateway_identity, 1024, signature);
+        let serialized_credential = credential.to_bytes();
+        let deserialized_credential = TokenCredential::from_bytes(&serialized_credential).unwrap();
+        assert_eq!(
+            credential.verification_key,
+            deserialized_credential.verification_key
+        );
+        assert_eq!(
+            credential.gateway_identity,
+            deserialized_credential.gateway_identity
+        );
+        assert_eq!(credential.bandwidth, deserialized_credential.bandwidth);
+        assert_eq!(
+            credential.signature.to_bytes(),
+            deserialized_credential.signature.to_bytes()
+        );
+    }
+}

common/credentials/src/token/mod.rs

@@ -0,0 +1,4 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+pub mod bandwidth;

common/crypto/src/hkdf.rs

@@ -5,18 +5,13 @@ use digest::{BlockInput, FixedOutput, Reset, Update};
 use generic_array::ArrayLength;
 use hkdf::Hkdf;
 
-#[derive(Debug)]
-pub enum HkdfError {
-    InvalidOkmLength,
-}
-
 /// Perform HKDF `extract` then `expand` as a single step.
 pub fn extract_then_expand<D>(
     salt: Option<&[u8]>,
     ikm: &[u8],
     info: Option<&[u8]>,
     okm_length: usize,
-) -> Result<Vec<u8>, HkdfError>
+) -> Result<Vec<u8>, hkdf::InvalidLength>
 where
     D: Update + BlockInput + FixedOutput + Reset + Default + Clone,
     D::BlockSize: ArrayLength<u8>,
@@ -27,9 +22,7 @@ where
 
     let hkdf = Hkdf::<D>::new(salt, ikm);
     let mut okm = vec![0u8; okm_length];
-    if hkdf.expand(info.unwrap_or_else(|| &[]), &mut okm).is_err() {
-        return Err(HkdfError::InvalidOkmLength);
-    }
+    hkdf.expand(info.unwrap_or_else(|| &[]), &mut okm)?;
 
     Ok(okm)
 }

common/erc20-bridge-contract/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "erc20-bridge-contract"
+version = "0.1.0"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+schemars = "0.8"
+serde = { version = "1.0.103", default-features = false, features = ["derive"] }

common/erc20-bridge-contract/src/keys.rs

@@ -0,0 +1,45 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+// Serializable structures for what we find in common/crypto
+#[derive(Serialize, Deserialize, Copy, Clone, Debug, PartialEq, JsonSchema)]
+pub struct PublicKey([u8; 32]);
+
+impl PublicKey {
+    pub fn new(bytes: [u8; 32]) -> Self {
+        PublicKey(bytes)
+    }
+    pub fn to_bytes(&self) -> [u8; 32] {
+        self.0
+    }
+}
+
+impl AsRef<[u8]> for PublicKey {
+    #[inline]
+    fn as_ref(&self) -> &[u8] {
+        &self.0
+    }
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
+pub struct Signature([u8; 32], [u8; 32]);
+
+impl Signature {
+    pub fn new(bytes: [u8; 64]) -> Self {
+        let mut sig1 = [0u8; 32];
+        let mut sig2 = [0u8; 32];
+        sig1.copy_from_slice(&bytes[..32]);
+        sig2.copy_from_slice(&bytes[32..]);
+
+        Signature(sig1, sig2)
+    }
+    pub fn to_bytes(&self) -> [u8; 64] {
+        let mut res = [0u8; 64];
+        res[..32].copy_from_slice(&self.0);
+        res[32..].copy_from_slice(&self.1);
+        res
+    }
+}

common/erc20-bridge-contract/src/lib.rs

@@ -0,0 +1,3 @@
+pub mod keys;
+pub mod msg;
+pub mod payment;

common/erc20-bridge-contract/src/msg.rs

@@ -0,0 +1,30 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+use crate::keys::PublicKey;
+use crate::payment::LinkPaymentData;
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
+pub struct InstantiateMsg {}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
+#[serde(rename_all = "snake_case")]
+pub enum ExecuteMsg {
+    LinkPayment { data: LinkPaymentData },
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
+#[serde(rename_all = "snake_case")]
+pub enum QueryMsg {
+    GetPayments {
+        limit: Option<u32>,
+        start_after: Option<PublicKey>,
+    },
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
+#[serde(rename_all = "snake_case")]
+pub struct MigrateMsg {}

common/erc20-bridge-contract/src/payment.rs

@@ -0,0 +1,73 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+use crate::keys::{PublicKey, Signature};
+
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize, JsonSchema)]
+pub struct Payment {
+    verification_key: PublicKey,
+    gateway_identity: PublicKey,
+    bandwidth: u64,
+}
+
+impl Payment {
+    pub fn new(verification_key: PublicKey, gateway_identity: PublicKey, bandwidth: u64) -> Self {
+        Payment {
+            verification_key,
+            gateway_identity,
+            bandwidth,
+        }
+    }
+
+    pub fn verification_key(&self) -> PublicKey {
+        self.verification_key
+    }
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
+pub struct LinkPaymentData {
+    pub verification_key: PublicKey,
+    pub gateway_identity: PublicKey,
+    pub bandwidth: u64,
+    pub signature: Signature,
+}
+
+impl LinkPaymentData {
+    pub fn new(
+        verification_key: [u8; 32],
+        gateway_identity: [u8; 32],
+        bandwidth: u64,
+        signature: [u8; 64],
+    ) -> Self {
+        LinkPaymentData {
+            verification_key: PublicKey::new(verification_key),
+            gateway_identity: PublicKey::new(gateway_identity),
+            bandwidth,
+            signature: Signature::new(signature),
+        }
+    }
+}
+
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize, JsonSchema)]
+pub struct PagedPaymentResponse {
+    pub payments: Vec<Payment>,
+    pub per_page: usize,
+    pub start_next_after: Option<PublicKey>,
+}
+
+impl PagedPaymentResponse {
+    pub fn new(
+        payments: Vec<Payment>,
+        per_page: usize,
+        start_next_after: Option<PublicKey>,
+    ) -> Self {
+        PagedPaymentResponse {
+            payments,
+            per_page,
+            start_next_after,
+        }
+    }
+}

common/mixnet-contract/Cargo.toml

@@ -8,10 +8,18 @@ edition = "2018"
 
 [dependencies]
 # this branch is identical to 0.14.1 with addition of updated k256 dependency required to help poor cargo choose correct version
-cosmwasm-std = { git = "https://github.com/jstuczyn/cosmwasm", branch="0.14.1-updatedk256" }
+cosmwasm-std = { git = "https://github.com/jstuczyn/cosmwasm", branch = "0.14.1-updatedk256" }
 #cosmwasm-std = { version = "0.14.1" }
 
 serde = { version = "1.0", features = ["derive"] }
 serde_repr = "0.1"
 schemars = "0.8"
-ts-rs = "3.0"
+ts-rs = { version = "5.1", optional = true }
+thiserror = "1.0"
+network-defaults = { path = "../network-defaults" }
+fixed = { version = "1.1", features = ["serde"] }
+az = "1.1"
+log = "0.4.14"
+
+[features]
+default = []

common/mixnet-contract/src/delegation.rs

@@ -120,48 +120,6 @@ impl PagedReverseMixDelegationsResponse {
     }
 }
 
-#[derive(Clone, Debug, Deserialize, PartialEq, Serialize, JsonSchema)]
-pub struct PagedGatewayDelegationsResponse {
-    pub node_identity: IdentityKey,
-    pub delegations: Vec<Delegation>,
-    pub start_next_after: Option<Addr>,
-}
-
-impl PagedGatewayDelegationsResponse {
-    pub fn new(
-        node_identity: IdentityKey,
-        delegations: Vec<Delegation>,
-        start_next_after: Option<Addr>,
-    ) -> Self {
-        PagedGatewayDelegationsResponse {
-            node_identity,
-            delegations,
-            start_next_after,
-        }
-    }
-}
-
-#[derive(Clone, Debug, Deserialize, PartialEq, Serialize, JsonSchema)]
-pub struct PagedReverseGatewayDelegationsResponse {
-    pub delegation_owner: Addr,
-    pub delegated_nodes: Vec<IdentityKey>,
-    pub start_next_after: Option<IdentityKey>,
-}
-
-impl PagedReverseGatewayDelegationsResponse {
-    pub fn new(
-        delegation_owner: Addr,
-        delegated_nodes: Vec<IdentityKey>,
-        start_next_after: Option<IdentityKey>,
-    ) -> Self {
-        PagedReverseGatewayDelegationsResponse {
-            delegation_owner,
-            delegated_nodes,
-            start_next_after,
-        }
-    }
-}
-
 #[derive(Clone, Debug, Deserialize, PartialEq, Serialize, JsonSchema)]
 pub struct PagedAllDelegationsResponse<T> {
     pub delegations: Vec<UnpackedDelegation<T>>,

common/mixnet-contract/src/error.rs

@@ -0,0 +1,9 @@
+use thiserror::Error;
+
+#[derive(Error, Debug, PartialEq)]
+pub enum MixnetContractError {
+    #[error("Overflow Error")]
+    OverflowError(#[from] cosmwasm_std::OverflowError),
+    #[error("reward_blockstamp field not set, set_reward_blockstamp must be called before attempting to issue rewards")]
+    BlockstampNotSet,
+}

common/mixnet-contract/src/gateway.rs

@@ -2,16 +2,14 @@
 #![allow(clippy::field_reassign_with_default)]
 
 use crate::{IdentityKey, SphinxKey};
-use cosmwasm_std::{coin, Addr, Coin};
+use cosmwasm_std::{Addr, Coin};
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use std::cmp::Ordering;
 use std::fmt::Display;
-use ts_rs::TS;
 
-use crate::current_block_height;
-
-#[derive(Clone, Debug, Deserialize, PartialEq, PartialOrd, Serialize, JsonSchema, TS)]
+#[cfg_attr(feature = "ts-rs", derive(ts_rs::TS))]
+#[derive(Clone, Debug, Deserialize, PartialEq, PartialOrd, Serialize, JsonSchema)]
 pub struct Gateway {
     pub host: String,
     pub mix_port: u16,
@@ -26,9 +24,7 @@ pub struct Gateway {
 #[derive(Clone, Debug, Deserialize, PartialEq, Serialize, JsonSchema)]
 pub struct GatewayBond {
     pub bond_amount: Coin,
-    pub total_delegation: Coin,
     pub owner: Addr,
-    #[serde(default = "current_block_height")]
     pub block_height: u64,
     pub gateway: Gateway,
 }
@@ -36,7 +32,6 @@ pub struct GatewayBond {
 impl GatewayBond {
     pub fn new(bond_amount: Coin, owner: Addr, block_height: u64, gateway: Gateway) -> Self {
         GatewayBond {
-            total_delegation: coin(0, &bond_amount.denom),
             bond_amount,
             owner,
             block_height,
@@ -64,27 +59,11 @@ impl GatewayBond {
 impl PartialOrd for GatewayBond {
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
         // first remove invalid cases
-        if self.bond_amount.denom != self.total_delegation.denom {
-            return None;
-        }
-
-        if other.bond_amount.denom != other.total_delegation.denom {
-            return None;
-        }
-
         if self.bond_amount.denom != other.bond_amount.denom {
             return None;
         }
 
-        // try to order by total bond + delegation
-        let total_cmp = (self.bond_amount.amount + self.total_delegation.amount)
-            .partial_cmp(&(self.bond_amount.amount + self.total_delegation.amount))?;
-
-        if total_cmp != Ordering::Equal {
-            return Some(total_cmp);
-        }
-
-        // then if those are equal, prefer higher bond over delegation
+        // try to order by total bond
         let bond_cmp = self
             .bond_amount
             .amount
@@ -93,15 +72,6 @@ impl PartialOrd for GatewayBond {
             return Some(bond_cmp);
         }
 
-        // then look at delegation (I'm not sure we can get here, but better safe than sorry)
-        let delegation_cmp = self
-            .total_delegation
-            .amount
-            .partial_cmp(&other.total_delegation.amount)?;
-        if delegation_cmp != Ordering::Equal {
-            return Some(delegation_cmp);
-        }
-
         // then check block height
         let height_cmp = self.block_height.partial_cmp(&other.block_height)?;
         if height_cmp != Ordering::Equal {
@@ -175,20 +145,19 @@ mod tests {
     #[test]
     fn gateway_bond_partial_ord() {
         let _150foos = Coin::new(150, "foo");
+        let _140foos = Coin::new(140, "foo");
         let _50foos = Coin::new(50, "foo");
         let _0foos = Coin::new(0, "foo");
 
         let gate1 = GatewayBond {
             bond_amount: _150foos.clone(),
-            total_delegation: _50foos.clone(),
             owner: Addr::unchecked("foo1"),
             block_height: 100,
             gateway: gateway_fixture(),
         };
 
         let gate2 = GatewayBond {
-            bond_amount: _150foos.clone(),
-            total_delegation: _50foos.clone(),
+            bond_amount: _150foos,
             owner: Addr::unchecked("foo2"),
             block_height: 120,
             gateway: gateway_fixture(),
@@ -196,15 +165,13 @@ mod tests {
 
         let gate3 = GatewayBond {
             bond_amount: _50foos,
-            total_delegation: _150foos.clone(),
             owner: Addr::unchecked("foo3"),
             block_height: 120,
             gateway: gateway_fixture(),
         };
 
         let gate4 = GatewayBond {
-            bond_amount: _150foos.clone(),
-            total_delegation: _0foos.clone(),
+            bond_amount: _140foos,
             owner: Addr::unchecked("foo4"),
             block_height: 120,
             gateway: gateway_fixture(),
@@ -212,21 +179,19 @@ mod tests {
 
         let gate5 = GatewayBond {
             bond_amount: _0foos,
-            total_delegation: _150foos,
             owner: Addr::unchecked("foo5"),
             block_height: 120,
             gateway: gateway_fixture(),
         };
 
         // summary:
-        // gate1: 150bond + 50delegation, foo1, 100
-        // gate2: 150bond + 50delegation, foo2, 120
-        // gate3: 50bond + 150delegation, foo3, 120
-        // gate4: 150bond + 0delegation, foo4, 120
-        // gate5: 0bond + 150delegation, foo5, 120
+        // gate1: 150bond, foo1, 100
+        // gate2: 150bond, foo2, 120
+        // gate3: 50bond, foo3, 120
+        // gate4: 140bond, foo4, 120
+        // gate5: 0bond, foo5, 120
 
-        // highest total bond+delegation is used
-        // then bond followed by delegation
+        // highest total bond is used
         // finally just the rest of the fields
 
         // gate1 has higher total than gate4 or gate5

common/mixnet-contract/src/lib.rs

@@ -2,25 +2,20 @@
 // SPDX-License-Identifier: Apache-2.0
 
 mod delegation;
+pub mod error;
 mod gateway;
-mod mixnode;
+pub mod mixnode;
 mod msg;
 mod types;
 
+pub const MIXNODE_DELEGATORS_PAGE_LIMIT: usize = 250;
+
 pub use cosmwasm_std::{Addr, Coin};
 pub use delegation::{
-    Delegation, PagedAllDelegationsResponse, PagedGatewayDelegationsResponse,
-    PagedMixDelegationsResponse, PagedReverseGatewayDelegationsResponse,
+    Delegation, PagedAllDelegationsResponse, PagedMixDelegationsResponse,
     PagedReverseMixDelegationsResponse, RawDelegationData, UnpackedDelegation,
 };
 pub use gateway::{Gateway, GatewayBond, GatewayOwnershipResponse, PagedGatewayResponse};
 pub use mixnode::{Layer, MixNode, MixNodeBond, MixOwnershipResponse, PagedMixnodeResponse};
 pub use msg::{ExecuteMsg, InstantiateMsg, MigrateMsg, QueryMsg};
-pub use types::{IdentityKey, IdentityKeyRef, LayerDistribution, SphinxKey, StateParams};
-
-use std::sync::atomic::{AtomicU64, Ordering};
-pub static CURRENT_BLOCK_HEIGHT: AtomicU64 = AtomicU64::new(0);
-
-pub fn current_block_height() -> u64 {
-    CURRENT_BLOCK_HEIGHT.load(Ordering::Relaxed)
-}
+pub use types::*;

common/mixnet-contract/src/mixnode.rs

@@ -2,17 +2,24 @@
 #![allow(clippy::field_reassign_with_default)]
 
 use crate::{IdentityKey, SphinxKey};
-use cosmwasm_std::{coin, Addr, Coin};
+use az::CheckedCast;
+use cosmwasm_std::{coin, Addr, Coin, Uint128};
+use log::error;
+use network_defaults::{DEFAULT_OPERATOR_EPOCH_COST, DEFAULT_PROFIT_MARGIN};
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use serde_repr::{Deserialize_repr, Serialize_repr};
 use std::cmp::Ordering;
 use std::fmt::Display;
-use ts_rs::TS;
 
-use crate::current_block_height;
+type U128 = fixed::types::U75F53; // u128 with 18 significant digits
 
-#[derive(Clone, Debug, Deserialize, PartialEq, PartialOrd, Serialize, JsonSchema, TS)]
+fixed::const_fixed_from_int! {
+    const ONE: U128 = 1;
+}
+
+#[cfg_attr(feature = "ts-rs", derive(ts_rs::TS))]
+#[derive(Clone, Debug, Deserialize, PartialEq, PartialOrd, Serialize, JsonSchema)]
 pub struct MixNode {
     pub host: String,
     pub mix_port: u16,
@@ -25,7 +32,17 @@ pub struct MixNode {
 }
 
 #[derive(
-    Copy, Clone, Debug, Serialize_repr, PartialEq, PartialOrd, Deserialize_repr, JsonSchema,
+    Copy,
+    Clone,
+    Debug,
+    PartialEq,
+    Eq,
+    PartialOrd,
+    Ord,
+    Hash,
+    Serialize_repr,
+    Deserialize_repr,
+    JsonSchema,
 )]
 #[repr(u8)]
 pub enum Layer {
@@ -35,15 +52,190 @@ pub enum Layer {
     Three = 3,
 }
 
+#[derive(Debug, Clone, JsonSchema, PartialEq, Serialize, Deserialize, Copy)]
+pub struct NodeRewardParams {
+    period_reward_pool: Uint128,
+    k: Uint128,
+    reward_blockstamp: u64,
+    circulating_supply: Uint128,
+    uptime: Uint128,
+    sybil_resistance_percent: u8,
+}
+
+impl NodeRewardParams {
+    pub fn new(
+        period_reward_pool: u128,
+        k: u128,
+        reward_blockstamp: u64,
+        circulating_supply: u128,
+        uptime: u128,
+        sybil_resistance_percent: u8,
+    ) -> NodeRewardParams {
+        NodeRewardParams {
+            period_reward_pool: Uint128(period_reward_pool),
+            k: Uint128(k),
+            reward_blockstamp,
+            circulating_supply: Uint128(circulating_supply),
+            uptime: Uint128(uptime),
+            sybil_resistance_percent,
+        }
+    }
+
+    pub fn performance(&self) -> U128 {
+        U128::from_num(self.uptime.u128()) / U128::from_num(100)
+    }
+
+    pub fn operator_cost(&self) -> U128 {
+        U128::from_num(self.uptime.u128() / 100u128 * DEFAULT_OPERATOR_EPOCH_COST as u128)
+    }
+
+    pub fn set_reward_blockstamp(&mut self, blockstamp: u64) {
+        self.reward_blockstamp = blockstamp;
+    }
+
+    pub fn period_reward_pool(&self) -> u128 {
+        self.period_reward_pool.u128()
+    }
+
+    pub fn k(&self) -> u128 {
+        self.k.u128()
+    }
+
+    pub fn circulating_supply(&self) -> u128 {
+        self.circulating_supply.u128()
+    }
+
+    pub fn reward_blockstamp(&self) -> u64 {
+        self.reward_blockstamp
+    }
+
+    pub fn uptime(&self) -> u128 {
+        self.uptime.u128()
+    }
+
+    pub fn one_over_k(&self) -> U128 {
+        ONE / U128::from_num(self.k.u128())
+    }
+
+    pub fn alpha(&self) -> U128 {
+        U128::from_num(self.sybil_resistance_percent) / U128::from_num(100)
+    }
+}
+
+// cosmwasm's limited serde doesn't work with U128 directly
+#[allow(non_snake_case)]
+pub mod fixed_U128_as_string {
+    use super::U128;
+    use serde::de::Error;
+    use serde::Deserialize;
+    use std::str::FromStr;
+
+    pub fn serialize<S>(val: &U128, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        let s = (*val).to_string();
+        serializer.serialize_str(&s)
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<U128, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        U128::from_str(&s).map_err(|err| {
+            D::Error::custom(format!(
+                "failed to deserialize U128 with its string representation - {}",
+                err
+            ))
+        })
+    }
+}
+
+// everything required to reward delegator of given mixnode
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, JsonSchema)]
+pub struct DelegatorRewardParams {
+    node_reward_params: NodeRewardParams,
+
+    // to be completely honest I don't understand all consequences of using `#[schemars(with = "String")]`
+    // for U128 here, but it seems that CosmWasm is using the same attribute for their Uint128
+    #[schemars(with = "String")]
+    #[serde(with = "fixed_U128_as_string")]
+    sigma: U128,
+    #[schemars(with = "String")]
+    #[serde(with = "fixed_U128_as_string")]
+    profit_margin: U128,
+    #[schemars(with = "String")]
+    #[serde(with = "fixed_U128_as_string")]
+    node_profit: U128,
+}
+
+impl DelegatorRewardParams {
+    pub fn new(mixnode_bond: &MixNodeBond, node_reward_params: NodeRewardParams) -> Self {
+        DelegatorRewardParams {
+            sigma: mixnode_bond.sigma(&node_reward_params),
+            profit_margin: mixnode_bond.profit_margin(),
+            node_profit: mixnode_bond.node_profit(&node_reward_params),
+            node_reward_params,
+        }
+    }
+
+    pub fn determine_delegation_reward(&self, delegation_amount: Uint128) -> u128 {
+        // change all values into their fixed representations
+        let delegation_amount = U128::from_num(delegation_amount.u128());
+        let circulating_supply = U128::from_num(self.node_reward_params.circulating_supply());
+
+        let scaled_delegation_amount = delegation_amount / circulating_supply;
+        let delegator_reward =
+            (ONE - self.profit_margin) * scaled_delegation_amount / self.sigma * self.node_profit;
+
+        let reward = delegator_reward.max(U128::ZERO);
+        if let Some(int_reward) = reward.checked_cast() {
+            int_reward
+        } else {
+            error!(
+                "Could not cast delegator reward ({}) to u128, returning 0",
+                reward,
+            );
+            0u128
+        }
+    }
+
+    pub fn node_reward_params(&self) -> &NodeRewardParams {
+        &self.node_reward_params
+    }
+}
+
+#[derive(Debug)]
+pub struct NodeRewardResult {
+    reward: U128,
+    lambda: U128,
+    sigma: U128,
+}
+
+impl NodeRewardResult {
+    pub fn reward(&self) -> U128 {
+        self.reward
+    }
+
+    pub fn lambda(&self) -> U128 {
+        self.lambda
+    }
+
+    pub fn sigma(&self) -> U128 {
+        self.sigma
+    }
+}
+
 #[derive(Clone, Debug, Deserialize, PartialEq, Serialize, JsonSchema)]
 pub struct MixNodeBond {
     pub bond_amount: Coin,
     pub total_delegation: Coin,
     pub owner: Addr,
     pub layer: Layer,
-    #[serde(default = "current_block_height")]
     pub block_height: u64,
     pub mix_node: MixNode,
+    pub profit_margin_percent: Option<u8>,
 }
 
 impl MixNodeBond {
@@ -53,6 +245,7 @@ impl MixNodeBond {
         layer: Layer,
         block_height: u64,
         mix_node: MixNode,
+        profit_margin_percent: Option<u8>,
     ) -> Self {
         MixNodeBond {
             total_delegation: coin(0, &bond_amount.denom),
@@ -61,9 +254,15 @@ impl MixNodeBond {
             layer,
             block_height,
             mix_node,
+            profit_margin_percent,
         }
     }
 
+    pub fn profit_margin(&self) -> U128 {
+        U128::from_num(self.profit_margin_percent.unwrap_or(DEFAULT_PROFIT_MARGIN))
+            / U128::from_num(100)
+    }
+
     pub fn identity(&self) -> &String {
         &self.mix_node.identity_key
     }
@@ -79,6 +278,107 @@ impl MixNodeBond {
     pub fn mix_node(&self) -> &MixNode {
         &self.mix_node
     }
+
+    pub fn total_stake(&self) -> Option<u128> {
+        if self.bond_amount.denom != self.total_delegation.denom {
+            None
+        } else {
+            Some(self.bond_amount.amount.u128() + self.total_delegation.amount.u128())
+        }
+    }
+
+    pub fn total_delegation(&self) -> Coin {
+        self.total_delegation.clone()
+    }
+
+    pub fn bond_to_circulating_supply(&self, circulating_supply: u128) -> U128 {
+        U128::from_num(self.bond_amount().amount.u128()) / U128::from_num(circulating_supply)
+    }
+
+    pub fn total_stake_to_circulating_supply(&self, circulating_supply: u128) -> U128 {
+        U128::from_num(self.bond_amount().amount.u128() + self.total_delegation().amount.u128())
+            / U128::from_num(circulating_supply)
+    }
+
+    pub fn lambda(&self, params: &NodeRewardParams) -> U128 {
+        // Ratio of a bond to the token circulating supply
+        let bond_to_circulating_supply_ratio =
+            self.bond_to_circulating_supply(params.circulating_supply());
+        bond_to_circulating_supply_ratio.min(params.one_over_k())
+    }
+
+    pub fn sigma(&self, params: &NodeRewardParams) -> U128 {
+        // Ratio of a delegation to the the token circulating supply
+        let total_stake_to_circulating_supply_ratio =
+            self.total_stake_to_circulating_supply(params.circulating_supply());
+        total_stake_to_circulating_supply_ratio.min(params.one_over_k())
+    }
+
+    pub fn reward(&self, params: &NodeRewardParams) -> NodeRewardResult {
+        // Assuming uniform work distribution across the network this is one_over_k * k
+        let omega_k = ONE;
+        let lambda = self.lambda(params);
+        let sigma = self.sigma(params);
+
+        let reward = params.performance()
+            * params.period_reward_pool()
+            * (sigma * omega_k + params.alpha() * lambda * sigma * params.k())
+            / (ONE + params.alpha());
+
+        NodeRewardResult {
+            reward,
+            lambda,
+            sigma,
+        }
+    }
+
+    pub fn node_profit(&self, params: &NodeRewardParams) -> U128 {
+        if self.reward(params).reward() < params.operator_cost() {
+            U128::from_num(0)
+        } else {
+            self.reward(params).reward() - params.operator_cost()
+        }
+    }
+
+    pub fn operator_reward(&self, params: &NodeRewardParams) -> u128 {
+        let reward = self.reward(params);
+        let profit = if reward.reward < params.operator_cost() {
+            U128::from_num(0)
+        } else {
+            reward.reward - params.operator_cost()
+        };
+        let operator_base_reward = reward.reward.min(params.operator_cost());
+        let operator_reward = (self.profit_margin()
+            + (ONE - self.profit_margin()) * reward.lambda / reward.sigma)
+            * profit;
+
+        let reward = (operator_reward + operator_base_reward).max(U128::from_num(0));
+
+        if let Some(int_reward) = reward.checked_cast() {
+            int_reward
+        } else {
+            error!(
+                "Could not cast reward ({}) to u128, returning 0 - mixnode {}",
+                reward,
+                self.identity()
+            );
+            0u128
+        }
+    }
+
+    pub fn sigma_ratio(&self, params: &NodeRewardParams) -> U128 {
+        if self.total_stake_to_circulating_supply(params.circulating_supply()) < params.one_over_k()
+        {
+            self.total_stake_to_circulating_supply(params.circulating_supply())
+        } else {
+            params.one_over_k()
+        }
+    }
+
+    pub fn reward_delegation(&self, delegation_amount: Uint128, params: &NodeRewardParams) -> u128 {
+        let reward_params = DelegatorRewardParams::new(self, *params);
+        reward_params.determine_delegation_reward(delegation_amount)
+    }
 }
 
 impl PartialOrd for MixNodeBond {
@@ -210,6 +510,7 @@ mod tests {
             layer: Layer::One,
             block_height: 100,
             mix_node: mixnode_fixture(),
+            profit_margin_percent: Some(10),
         };
 
         let mix2 = MixNodeBond {
@@ -219,6 +520,7 @@ mod tests {
             layer: Layer::One,
             block_height: 120,
             mix_node: mixnode_fixture(),
+            profit_margin_percent: Some(10),
         };
 
         let mix3 = MixNodeBond {
@@ -228,6 +530,7 @@ mod tests {
             layer: Layer::One,
             block_height: 120,
             mix_node: mixnode_fixture(),
+            profit_margin_percent: Some(10),
         };
 
         let mix4 = MixNodeBond {
@@ -237,6 +540,7 @@ mod tests {
             layer: Layer::One,
             block_height: 120,
             mix_node: mixnode_fixture(),
+            profit_margin_percent: Some(10),
         };
 
         let mix5 = MixNodeBond {
@@ -246,6 +550,7 @@ mod tests {
             layer: Layer::One,
             block_height: 120,
             mix_node: mixnode_fixture(),
+            profit_margin_percent: Some(10),
         };
 
         // summary:

common/mixnet-contract/src/msg.rs

@@ -1,6 +1,7 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
+use crate::mixnode::NodeRewardParams;
 use crate::StateParams;
 use crate::{Gateway, IdentityKey, MixNode};
 use cosmwasm_std::Addr;
@@ -31,24 +32,29 @@ pub enum ExecuteMsg {
         mix_identity: IdentityKey,
     },
 
-    DelegateToGateway {
-        gateway_identity: IdentityKey,
+    BeginMixnodeRewarding {
+        // nonce of the current rewarding interval
+        rewarding_interval_nonce: u32,
     },
 
-    UndelegateFromGateway {
-        gateway_identity: IdentityKey,
+    FinishMixnodeRewarding {
+        // nonce of the current rewarding interval
+        rewarding_interval_nonce: u32,
     },
 
-    RewardMixnode {
+    RewardMixnodeV2 {
         identity: IdentityKey,
         // percentage value in range 0-100
-        uptime: u32,
+        params: NodeRewardParams,
+
+        // nonce of the current rewarding interval
+        rewarding_interval_nonce: u32,
     },
 
-    RewardGateway {
-        identity: IdentityKey,
-        // percentage value in range 0-100
-        uptime: u32,
+    RewardNextMixDelegators {
+        mix_identity: IdentityKey,
+        // nonce of the current rewarding interval
+        rewarding_interval_nonce: u32,
     },
 }
 
@@ -70,6 +76,7 @@ pub enum QueryMsg {
         address: Addr,
     },
     StateParams {},
+    CurrentRewardingInterval {},
     GetMixDelegations {
         mix_identity: IdentityKey,
         start_after: Option<Addr>,
@@ -88,25 +95,15 @@ pub enum QueryMsg {
         mix_identity: IdentityKey,
         address: Addr,
     },
-    GetGatewayDelegations {
-        gateway_identity: IdentityKey,
-        start_after: Option<Addr>,
-        limit: Option<u32>,
-    },
-    GetAllGatewayDelegations {
-        start_after: Option<Vec<u8>>,
-        limit: Option<u32>,
-    },
-    GetReverseGatewayDelegations {
-        delegation_owner: Addr,
-        start_after: Option<IdentityKey>,
-        limit: Option<u32>,
-    },
-    GetGatewayDelegation {
-        gateway_identity: IdentityKey,
-        address: Addr,
-    },
     LayerDistribution {},
+    GetRewardPool {},
+    GetCirculatingSupply {},
+    GetEpochRewardPercent {},
+    GetSybilResistancePercent {},
+    GetRewardingStatus {
+        mix_identity: IdentityKey,
+        rewarding_interval_nonce: u32,
+    },
 }
 
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]

common/mixnet-contract/src/types.rs

@@ -1,8 +1,9 @@
 // Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
 // SPDX-License-Identifier: Apache-2.0
 
+use crate::mixnode::DelegatorRewardParams;
 use crate::Layer;
-use cosmwasm_std::{Decimal, Uint128};
+use cosmwasm_std::Uint128;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use std::fmt::{self, Display, Formatter};
@@ -26,59 +27,76 @@ impl LayerDistribution {
     }
 }
 
+#[derive(Debug, Default, Serialize, Deserialize, Copy, Clone, Eq, PartialEq)]
+pub struct RewardingIntervalResponse {
+    pub current_rewarding_interval_starting_block: u64,
+    pub current_rewarding_interval_nonce: u32,
+    pub rewarding_in_progress: bool,
+}
+
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
 pub struct StateParams {
-    pub epoch_length: u32, // length of an epoch, expressed in hours
-
+    // so currently epoch_length is being unused and validator API performs rewarding
+    // based on its own epoch length config value. I guess that's fine for time being
+    // however, in the future, the contract constant should be controlling it instead.
+    // pub epoch_length: u32, // length of a rewarding epoch/interval, expressed in hours
     pub minimum_mixnode_bond: Uint128, // minimum amount a mixnode must bond to get into the system
     pub minimum_gateway_bond: Uint128, // minimum amount a gateway must bond to get into the system
-    pub mixnode_bond_reward_rate: Decimal, // annual reward rate, expressed as a decimal like 1.25
-    pub gateway_bond_reward_rate: Decimal, // annual reward rate, expressed as a decimal like 1.25
-    pub mixnode_delegation_reward_rate: Decimal, // annual reward rate, expressed as a decimal like 1.25
-    pub gateway_delegation_reward_rate: Decimal, // annual reward rate, expressed as a decimal like 1.25
+
+    // number of mixnode that are going to get rewarded during current rewarding interval (k_m)
+    // based on overall demand for private bandwidth-
+    pub mixnode_rewarded_set_size: u32,
+
+    // subset of rewarded mixnodes that are actively receiving mix traffic
+    // used to handle shorter-term (e.g. hourly) fluctuations of demand
     pub mixnode_active_set_size: u32,
-    pub gateway_active_set_size: u32,
 }
 
 impl Display for StateParams {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         write!(f, "Contract state parameters: [ ")?;
-        write!(f, "epoch length: {}; ", self.epoch_length)?;
         write!(f, "minimum mixnode bond: {}; ", self.minimum_mixnode_bond)?;
         write!(f, "minimum gateway bond: {}; ", self.minimum_gateway_bond)?;
         write!(
             f,
-            "mixnode bond reward rate: {}; ",
-            self.mixnode_bond_reward_rate
-        )?;
-        write!(
-            f,
-            "gateway bond reward rate: {}; ",
-            self.gateway_bond_reward_rate
-        )?;
-        write!(
-            f,
-            "mixnode delegation reward rate: {}; ",
-            self.mixnode_delegation_reward_rate
-        )?;
-        write!(
-            f,
-            "gateway delegation reward rate: {}; ",
-            self.gateway_delegation_reward_rate
+            "mixnode rewarded set size: {}",
+            self.mixnode_rewarded_set_size
         )?;
         write!(
             f,
             "mixnode active set size: {}",
             self.mixnode_active_set_size
-        )?;
-        write!(
-            f,
-            "gateway active set size: {} ]",
-            self.gateway_active_set_size
         )
     }
 }
 
+#[derive(Default, Debug, Serialize, Deserialize, PartialEq)]
+pub struct RewardingResult {
+    pub operator_reward: Uint128,
+    pub total_delegator_reward: Uint128,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct PendingDelegatorRewarding {
+    // keep track of the running rewarding results so we'd known how much was the operator and its delegators rewarded
+    pub running_results: RewardingResult,
+
+    pub next_start: String,
+
+    pub rewarding_params: DelegatorRewardParams,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub enum RewardingStatus {
+    Complete(RewardingResult),
+    PendingNextDelegatorPage(PendingDelegatorRewarding),
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct MixnodeRewardingStatusResponse {
+    pub status: Option<RewardingStatus>,
+}
+
 // type aliases for better reasoning about available data
 pub type IdentityKey = String;
 pub type IdentityKeyRef<'a> = &'a str;

common/network-defaults/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+hex-literal = "0.3.3"
 serde = {version = "1.0", features = ["derive"]}
 url = "2.2"
 time = { version = "0.3", features = ["macros"] }

common/network-defaults/src/eth_contract.rs

@@ -0,0 +1,132 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+// This should be modified whenever an updated Ethereum contract is uploaded
+pub const ETH_JSON_ABI: &str = r#"
+[
+  {
+    "inputs": [
+      {
+        "internalType": "contract ERC20Burnable",
+        "name": "_erc20",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "nonpayable",
+    "type": "constructor"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": false,
+        "internalType": "uint256",
+        "name": "Bandwidth",
+        "type": "uint256"
+      },
+      {
+        "indexed": true,
+        "internalType": "uint256",
+        "name": "VerificationKey",
+        "type": "uint256"
+      },
+      {
+        "indexed": false,
+        "internalType": "bytes",
+        "name": "SignedVerificationKey",
+        "type": "bytes"
+      }
+    ],
+    "name": "Burned",
+    "type": "event"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "previousOwner",
+        "type": "address"
+      },
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "newOwner",
+        "type": "address"
+      }
+    ],
+    "name": "OwnershipTransferred",
+    "type": "event"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "uint256",
+        "name": "amount",
+        "type": "uint256"
+      },
+      {
+        "internalType": "uint256",
+        "name": "verificationKey",
+        "type": "uint256"
+      },
+      {
+        "internalType": "bytes",
+        "name": "signedVerificationKey",
+        "type": "bytes"
+      }
+    ],
+    "name": "burnTokenForAccessCode",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "erc20",
+    "outputs": [
+      {
+        "internalType": "contract ERC20Burnable",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "owner",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "renounceOwnership",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "newOwner",
+        "type": "address"
+      }
+    ],
+    "name": "transferOwnership",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  }
+]
+        "#;

common/network-defaults/src/lib.rs

@@ -5,6 +5,8 @@ use std::time::Duration;
 use time::OffsetDateTime;
 use url::Url;
 
+pub mod eth_contract;
+
 #[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct ValidatorDetails {
     // it is assumed those values are always valid since they're being provided in our defaults file
@@ -61,7 +63,24 @@ pub fn default_api_endpoints() -> Vec<Url> {
 }
 
 pub const DEFAULT_MIXNET_CONTRACT_ADDRESS: &str = "punk10pyejy66429refv3g35g2t7am0was7yalwrzen";
-pub const NETWORK_MONITOR_ADDRESS: &str = "punk1v9qauwdq5terag6uvfsdytcs2d0sdmfdy7hgk3";
+pub const REWARDING_VALIDATOR_ADDRESS: &str = "punk1v9qauwdq5terag6uvfsdytcs2d0sdmfdy7hgk3";
+
+/// How much bandwidth (in bytes) one token can buy
+const BYTES_PER_TOKEN: u64 = 1024 * 1024 * 1024;
+/// How many ERC20 tokens should be burned to buy bandwidth
+pub const TOKENS_TO_BURN: u64 = 10;
+/// Default bandwidth (in bytes) that we try to buy
+pub const BANDWIDTH_VALUE: u64 = TOKENS_TO_BURN * BYTES_PER_TOKEN;
+
+// Ethereum constants used for token bridge
+pub const ETH_CONTRACT_ADDRESS: [u8; 20] =
+    hex_literal::hex!("9fEE3e28c17dbB87310A51F13C4fbf4331A6f102");
+pub const ETH_MIN_BLOCK_DEPTH: usize = 7;
+pub const COSMOS_CONTRACT_ADDRESS: &str = "punk1jld76tqw4wnpfenmay2xkv86nr3j0w426eka82";
+// Name of the event triggered by the eth contract. If the event name is changed,
+// this would also need to be changed; It is currently tested against the json abi
+pub const ETH_EVENT_NAME: &str = "Burned";
+pub const ETH_BURN_FUNCTION_NAME: &str = "burnTokenForAccessCode";
 
 /// Defaults Cosmos Hub/ATOM path
 pub const COSMOS_DERIVATION_PATH: &str = "m/44'/118'/0'/0/0";
@@ -93,4 +112,11 @@ pub const VALIDATOR_API_VERSION: &str = "v1";
 
 // REWARDING
 pub const DEFAULT_FIRST_EPOCH_START: OffsetDateTime = time::macros::datetime!(2021-08-23 12:00 UTC);
-pub const DEFAULT_EPOCH_LENGTH: Duration = Duration::from_secs(24 * 60 * 60); // 24h
+pub const DEFAULT_EPOCH_LENGTH: Duration = Duration::from_secs(24 * 60 * 60 * 30); // 30 days
+/// We'll be assuming a few more things, profit margin and cost function. Since we don't have relialable package measurement, we'll be using uptime. We'll also set the value of 1 Nym to 1 $, to be able to translate epoch costs to Nyms. We'll also assume a cost of 40$ per epoch(month), converting that to Nym at our 1$ rate translates to 40_000_000 uNyms
+pub const DEFAULT_OPERATOR_EPOCH_COST: u64 = 40_000_000; // 40$/(30 days) at 1 Nym == 1$
+
+// TODO: is there a way to get this from the chain
+pub const TOTAL_SUPPLY: u128 = 1_000_000_000_000_000;
+
+pub const DEFAULT_PROFIT_MARGIN: u8 = 10;

common/nymcoconut/Cargo.toml

@@ -0,0 +1,43 @@
+[package]
+name = "nymcoconut"
+version = "0.5.0"
+authors = ["Jedrzej Stuczynski <andrew@nymtech.net>", "Ania Piotrowska <ania@nymtech.net>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bls12_381 = { version = "0.5", default-features = false, features = ["pairings", "alloc", "experimental"] }
+itertools = "0.10"
+digest = "0.9"
+rand = "0.8"
+thiserror = "1.0"
+serde = "1.0"
+serde_derive = "1.0"
+bs58 = "0.4.0"
+sha2 = "0.9"
+
+[dependencies.ff]
+version = "0.10"
+default-features = false
+
+[dependencies.group]
+version = "0.10"
+default-features = false
+
+[dev-dependencies]
+criterion = { version="0.3", features=["html_reports"] }
+doc-comment = "0.3"
+
+[dev-dependencies.bincode]
+version = "1"
+
+#[[bench]]
+#name = "benchmarks"
+#harness = false
+
+[features]
+default = []
+
+[target.'cfg(target_env = "wasm32-unknown-unknown")'.dependencies]
+getrandom = { version="0.2", features=["js"] }

common/nymcoconut/src/elgamal.rs

@@ -0,0 +1,322 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use core::ops::{Deref, Mul};
+use std::convert::TryFrom;
+use std::convert::TryInto;
+
+use bls12_381::{G1Projective, Scalar};
+use group::Curve;
+use serde_derive::{Deserialize, Serialize};
+
+use crate::error::{CoconutError, Result};
+use crate::scheme::setup::Parameters;
+use crate::traits::{Base58, Bytable};
+use crate::utils::{try_deserialize_g1_projective, try_deserialize_scalar};
+
+/// Type alias for the ephemeral key generated during ElGamal encryption
+pub type EphemeralKey = Scalar;
+
+/// Two G1 points representing ElGamal ciphertext
+#[derive(Debug)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct Ciphertext(pub(crate) G1Projective, pub(crate) G1Projective);
+
+impl TryFrom<&[u8]> for Ciphertext {
+    type Error = CoconutError;
+
+    fn try_from(bytes: &[u8]) -> Result<Ciphertext> {
+        if bytes.len() != 96 {
+            return Err(CoconutError::Deserialization(format!(
+                "Ciphertext must be exactly 96 bytes, got {}",
+                bytes.len()
+            )));
+        }
+
+        let c1_bytes: &[u8; 48] = &bytes[..48].try_into().unwrap();
+        let c2_bytes: &[u8; 48] = &bytes[48..].try_into().unwrap();
+
+        let c1 = try_deserialize_g1_projective(
+            c1_bytes,
+            CoconutError::Deserialization("Failed to deserialize compressed c1".to_string()),
+        )?;
+        let c2 = try_deserialize_g1_projective(
+            c2_bytes,
+            CoconutError::Deserialization("Failed to deserialize compressed c2".to_string()),
+        )?;
+
+        Ok(Ciphertext(c1, c2))
+    }
+}
+
+impl Ciphertext {
+    pub fn c1(&self) -> &G1Projective {
+        &self.0
+    }
+
+    pub fn c2(&self) -> &G1Projective {
+        &self.1
+    }
+
+    pub fn to_bytes(&self) -> [u8; 96] {
+        let mut bytes = [0u8; 96];
+        bytes[..48].copy_from_slice(&self.0.to_affine().to_compressed());
+        bytes[48..].copy_from_slice(&self.1.to_affine().to_compressed());
+        bytes
+    }
+
+    pub fn from_bytes(bytes: &[u8]) -> Result<Ciphertext> {
+        Ciphertext::try_from(bytes)
+    }
+}
+
+/// PrivateKey used in the ElGamal encryption scheme to recover the plaintext
+#[derive(Debug)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct PrivateKey(pub(crate) Scalar);
+
+impl PrivateKey {
+    /// Decrypt takes the ElGamal encryption of a message and returns a point on the G1 curve
+    /// that represents original h^m.
+    pub fn decrypt(&self, ciphertext: &Ciphertext) -> G1Projective {
+        let (c1, c2) = &(ciphertext.0, ciphertext.1);
+
+        // (gamma^k * h^m) / (g1^{d * k})   |   note: gamma = g1^d
+        c2 - c1 * self.0
+    }
+
+    pub fn public_key(&self, params: &Parameters) -> PublicKey {
+        PublicKey(params.gen1() * self.0)
+    }
+
+    pub fn to_bytes(&self) -> [u8; 32] {
+        self.0.to_bytes()
+    }
+
+    pub fn from_bytes(bytes: &[u8; 32]) -> Result<PrivateKey> {
+        try_deserialize_scalar(
+            bytes,
+            CoconutError::Deserialization(
+                "Failed to deserialize ElGamal private key - it was not in the canonical form"
+                    .to_string(),
+            ),
+        )
+        .map(PrivateKey)
+    }
+}
+
+impl Bytable for PrivateKey {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        self.to_bytes().to_vec()
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self> {
+        PrivateKey::from_bytes(slice.try_into().unwrap())
+    }
+}
+
+impl Base58 for PrivateKey {}
+
+// TODO: perhaps be more explicit and apart from gamma also store generator and group order?
+/// PublicKey used in the ElGamal encryption scheme to produce the ciphertext
+#[derive(Debug, Clone)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct PublicKey(G1Projective);
+
+impl PublicKey {
+    /// Encrypt encrypts the given message in the form of h^m,
+    /// where h is a point on the G1 curve using the given public key.
+    /// The random k is returned alongside the encryption
+    /// as it is required by the Coconut Scheme to create proofs of knowledge.
+    pub fn encrypt(
+        &self,
+        params: &Parameters,
+        h: &G1Projective,
+        msg: &Scalar,
+    ) -> (Ciphertext, EphemeralKey) {
+        let k = params.random_scalar();
+        // c1 = g1^k
+        let c1 = params.gen1() * k;
+        // c2 = gamma^k * h^m
+        let c2 = self.0 * k + h * msg;
+
+        (Ciphertext(c1, c2), k)
+    }
+
+    pub fn to_bytes(&self) -> [u8; 48] {
+        self.to_byte_vec().try_into().unwrap()
+    }
+
+    pub fn from_bytes(bytes: &[u8; 48]) -> Result<PublicKey> {
+        Ok(PublicKey::try_from(bytes.to_vec().as_slice()).unwrap())
+    }
+}
+
+impl Bytable for PublicKey {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        self.0.to_affine().to_compressed().into()
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self> {
+        Ok(PublicKey::from_bytes(slice.try_into().unwrap()).unwrap())
+    }
+}
+
+impl TryFrom<&[u8]> for PublicKey {
+    type Error = CoconutError;
+
+    fn try_from(slice: &[u8]) -> Result<PublicKey> {
+        try_deserialize_g1_projective(
+            slice.try_into().unwrap(),
+            CoconutError::Deserialization(
+                "Failed to deserialize compressed ElGamal public key".to_string(),
+            ),
+        )
+        .map(PublicKey)
+    }
+}
+
+impl Base58 for PublicKey {}
+
+impl Deref for PublicKey {
+    type Target = G1Projective;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<'a, 'b> Mul<&'b Scalar> for &'a PublicKey {
+    type Output = G1Projective;
+
+    fn mul(self, rhs: &'b Scalar) -> Self::Output {
+        self.0 * rhs
+    }
+}
+
+#[derive(Serialize, Deserialize)]
+/// A convenient wrapper for both keys of the ElGamal keypair
+pub struct ElGamalKeyPair {
+    private_key: PrivateKey,
+    public_key: PublicKey,
+}
+
+impl ElGamalKeyPair {
+    pub fn public_key(&self) -> &PublicKey {
+        &self.public_key
+    }
+
+    pub fn private_key(&self) -> &PrivateKey {
+        &self.private_key
+    }
+}
+
+/// Generate a fresh ElGamal keypair using the group generator specified by the provided [Parameters]
+pub fn elgamal_keygen(params: &Parameters) -> ElGamalKeyPair {
+    let private_key = params.random_scalar();
+    let gamma = params.gen1() * private_key;
+
+    ElGamalKeyPair {
+        private_key: PrivateKey(private_key),
+        public_key: PublicKey(gamma),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn keygen() {
+        let params = Parameters::default();
+        let keypair = super::elgamal_keygen(&params);
+
+        let expected = params.gen1() * keypair.private_key.0;
+        let gamma = keypair.public_key.0;
+        assert_eq!(
+            expected, gamma,
+            "Public key, gamma, should be equal to g1^d, where d is the private key"
+        );
+    }
+
+    #[test]
+    fn encryption() {
+        let params = Parameters::default();
+        let keypair = super::elgamal_keygen(&params);
+
+        let r = params.random_scalar();
+        let h = params.gen1() * r;
+        let m = params.random_scalar();
+
+        let (ciphertext, ephemeral_key) = keypair.public_key.encrypt(&params, &h, &m);
+
+        let expected_c1 = params.gen1() * ephemeral_key;
+        assert_eq!(expected_c1, ciphertext.0, "c1 should be equal to g1^k");
+
+        let expected_c2 = keypair.public_key.0 * ephemeral_key + h * m;
+        assert_eq!(
+            expected_c2, ciphertext.1,
+            "c2 should be equal to gamma^k * h^m"
+        );
+    }
+
+    #[test]
+    fn decryption() {
+        let params = Parameters::default();
+        let keypair = super::elgamal_keygen(&params);
+
+        let r = params.random_scalar();
+        let h = params.gen1() * r;
+        let m = params.random_scalar();
+
+        let (ciphertext, _) = keypair.public_key.encrypt(&params, &h, &m);
+        let dec = keypair.private_key.decrypt(&ciphertext);
+
+        let expected = h * m;
+        assert_eq!(
+            expected, dec,
+            "after ElGamal decryption, original h^m should be obtained"
+        );
+    }
+
+    #[test]
+    fn private_key_bytes_roundtrip() {
+        let params = Parameters::default();
+        let private_key = PrivateKey(params.random_scalar());
+        let bytes = private_key.to_bytes();
+
+        // also make sure it is equivalent to the internal scalar's bytes
+        assert_eq!(private_key.0.to_bytes(), bytes);
+        assert_eq!(private_key, PrivateKey::from_bytes(&bytes).unwrap())
+    }
+
+    #[test]
+    fn public_key_bytes_roundtrip() {
+        let params = Parameters::default();
+        let r = params.random_scalar();
+        let public_key = PublicKey(params.gen1() * r);
+        let bytes = public_key.to_bytes();
+
+        // also make sure it is equivalent to the internal g1 compressed bytes
+        assert_eq!(public_key.0.to_affine().to_compressed(), bytes);
+        assert_eq!(public_key, PublicKey::from_bytes(&bytes).unwrap())
+    }
+
+    #[test]
+    fn ciphertext_bytes_roundtrip() {
+        let params = Parameters::default();
+        let r = params.random_scalar();
+        let s = params.random_scalar();
+        let ciphertext = Ciphertext(params.gen1() * r, params.gen1() * s);
+        let bytes = ciphertext.to_bytes();
+
+        // also make sure it is equivalent to the internal g1 compressed bytes concatenated
+        let expected_bytes = [
+            ciphertext.0.to_affine().to_compressed(),
+            ciphertext.1.to_affine().to_compressed(),
+        ]
+        .concat();
+        assert_eq!(expected_bytes, bytes);
+        assert_eq!(ciphertext, Ciphertext::try_from(&bytes[..]).unwrap())
+    }
+}

common/nymcoconut/src/error.rs

@@ -0,0 +1,53 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use thiserror::Error;
+
+/// A `Result` alias where the `Err` case is `coconut_rs::Error`.
+pub type Result<T> = std::result::Result<T, CoconutError>;
+
+#[derive(Error, Debug)]
+pub enum CoconutError {
+    #[error("Setup error: {0}")]
+    Setup(String),
+
+    #[error("encountered error during keygen")]
+    Keygen,
+
+    #[error("Issuance related error: {0}")]
+    Issuance(String),
+
+    #[error("Tried to prepare blind sign request for higher than specified number of attributes (max: {}, requested: {})", max, requested)]
+    IssuanceMaxAttributes { max: usize, requested: usize },
+
+    #[error("Interpolation error: {0}")]
+    Interpolation(String),
+
+    #[error("Aggregation error: {0}")]
+    Aggregation(String),
+
+    #[error("Unblind error: {0}")]
+    Unblind(String),
+
+    #[error("Verification error: {0}")]
+    Verification(String),
+
+    #[error("Deserialization error: {0}")]
+    Deserialization(String),
+
+    #[error(
+        "Deserailization error, expected at least {} bytes, got {}",
+        min,
+        actual
+    )]
+    DeserializationMinLength { min: usize, actual: usize },
+
+    #[error("Tried to deserialize {object} with bytes of invalid length. Expected {actual} < {} or {modulus_target} % {modulus} == 0")]
+    DeserializationInvalidLength {
+        actual: usize,
+        target: usize,
+        modulus_target: usize,
+        modulus: usize,
+        object: String,
+    },
+}

common/nymcoconut/src/impls/clone.rs

@@ -0,0 +1,15 @@
+use crate::{BlindSignRequest, BlindedSignature, Bytable, Theta};
+
+macro_rules! impl_clone {
+    ($struct:ident) => {
+        impl Clone for $struct {
+            fn clone(&self) -> Self {
+                Self::try_from_byte_slice(&self.to_byte_vec()).unwrap()
+            }
+        }
+    };
+}
+
+impl_clone!(BlindSignRequest);
+impl_clone!(BlindedSignature);
+impl_clone!(Theta);

common/nymcoconut/src/impls/mod.rs

@@ -0,0 +1,2 @@
+mod clone;
+mod serde;

common/nymcoconut/src/impls/serde.rs

@@ -0,0 +1,56 @@
+use crate::elgamal::PrivateKey;
+use crate::scheme::SecretKey;
+use crate::{
+    Base58, BlindSignRequest, BlindedSignature, PublicKey, Signature, Theta, VerificationKey,
+};
+use serde::de::Unexpected;
+use serde::{de::Error, de::Visitor, Deserialize, Deserializer, Serialize, Serializer};
+use std::fmt;
+
+macro_rules! impl_serde {
+    ($struct:ident, $visitor:ident) => {
+        pub struct $visitor {}
+
+        impl Serialize for $struct {
+            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+            where
+                S: Serializer,
+            {
+                serializer.serialize_str(&self.to_bs58())
+            }
+        }
+
+        impl<'de> Visitor<'de> for $visitor {
+            type Value = $struct;
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                write!(formatter, "A base58 encoded struct")
+            }
+
+            fn visit_str<E: Error>(self, s: &str) -> Result<Self::Value, E> {
+                match $struct::try_from_bs58(s) {
+                    Ok(x) => Ok(x),
+                    Err(_) => Err(Error::invalid_value(Unexpected::Str(s), &self)),
+                }
+            }
+        }
+
+        impl<'de> Deserialize<'de> for $struct {
+            fn deserialize<D>(deserializer: D) -> Result<$struct, D::Error>
+            where
+                D: Deserializer<'de>,
+            {
+                deserializer.deserialize_str($visitor {})
+            }
+        }
+    };
+}
+
+impl_serde!(SecretKey, V1);
+impl_serde!(VerificationKey, V2);
+impl_serde!(PublicKey, V3);
+impl_serde!(PrivateKey, V4);
+impl_serde!(BlindSignRequest, V5);
+impl_serde!(BlindedSignature, V6);
+impl_serde!(Signature, V7);
+impl_serde!(Theta, V8);

common/nymcoconut/src/lib.rs

@@ -0,0 +1,57 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use std::convert::TryInto;
+
+use bls12_381::Scalar;
+
+pub use elgamal::elgamal_keygen;
+pub use elgamal::ElGamalKeyPair;
+pub use elgamal::PublicKey;
+pub use error::CoconutError;
+pub use scheme::aggregation::aggregate_signature_shares;
+pub use scheme::aggregation::aggregate_verification_keys;
+pub use scheme::issuance::blind_sign;
+pub use scheme::issuance::prepare_blind_sign;
+pub use scheme::issuance::BlindSignRequest;
+pub use scheme::keygen::ttp_keygen;
+pub use scheme::keygen::KeyPair;
+pub use scheme::keygen::VerificationKey;
+pub use scheme::setup::setup;
+pub use scheme::setup::Parameters;
+pub use scheme::verification::prove_bandwidth_credential;
+pub use scheme::verification::verify_credential;
+pub use scheme::verification::Theta;
+pub use scheme::BlindedSignature;
+pub use scheme::Signature;
+pub use scheme::SignatureShare;
+pub use traits::Base58;
+pub use utils::hash_to_scalar;
+
+use crate::traits::Bytable;
+
+pub mod elgamal;
+mod error;
+mod impls;
+mod proofs;
+mod scheme;
+#[cfg(test)]
+mod tests;
+mod traits;
+mod utils;
+
+pub type Attribute = Scalar;
+pub type PrivateAttribute = Attribute;
+pub type PublicAttribute = Attribute;
+
+impl Bytable for Attribute {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        self.to_bytes().to_vec()
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self, CoconutError> {
+        Ok(Attribute::from_bytes(slice.try_into().unwrap()).unwrap())
+    }
+}
+
+impl Base58 for Attribute {}

common/nymcoconut/src/proofs/mod.rs

@@ -0,0 +1,663 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+// TODO: look at https://crates.io/crates/merlin to perhaps use it instead?
+
+use std::borrow::Borrow;
+use std::convert::TryInto;
+
+use bls12_381::{G1Projective, G2Projective, Scalar};
+use digest::generic_array::typenum::Unsigned;
+use digest::Digest;
+use group::GroupEncoding;
+use itertools::izip;
+use sha2::Sha256;
+
+use crate::elgamal::Ciphertext;
+use crate::error::{CoconutError, Result};
+use crate::scheme::setup::Parameters;
+use crate::scheme::VerificationKey;
+use crate::utils::{hash_g1, try_deserialize_scalar, try_deserialize_scalar_vec};
+use crate::{elgamal, Attribute, ElGamalKeyPair};
+
+// as per the reference python implementation
+type ChallengeDigest = Sha256;
+
+#[derive(Debug)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct ProofCmCs {
+    challenge: Scalar,
+    response_opening: Scalar,
+    response_private_elgamal_key: Scalar,
+    response_keys: Vec<Scalar>,
+    response_attributes: Vec<Scalar>,
+}
+
+// note: this is slightly different from the reference python implementation
+// as we omit the unnecessary string conversion. Instead we concatenate byte
+// representations together and hash that.
+// note2: G1 and G2 elements are using their compressed representations
+// and as per the bls12-381 library all elements are using big-endian form
+/// Generates a Scalar [or Fp] challenge by hashing a number of elliptic curve points.  
+fn compute_challenge<D, I, B>(iter: I) -> Scalar
+where
+    D: Digest,
+    I: Iterator<Item = B>,
+    B: AsRef<[u8]>,
+{
+    let mut h = D::new();
+    for point_representation in iter {
+        h.update(point_representation);
+    }
+    let digest = h.finalize();
+
+    // TODO: I don't like the 0 padding here (though it's what we've been using before,
+    // but we never had a security audit anyway...)
+    // instead we could maybe use the `from_bytes` variant and adding some suffix
+    // when computing the digest until we produce a valid scalar.
+    let mut bytes = [0u8; 64];
+    let pad_size = 64usize
+        .checked_sub(D::OutputSize::to_usize())
+        .unwrap_or_default();
+
+    bytes[pad_size..].copy_from_slice(&digest);
+
+    Scalar::from_bytes_wide(&bytes)
+}
+
+fn produce_response(witness: &Scalar, challenge: &Scalar, secret: &Scalar) -> Scalar {
+    witness - challenge * secret
+}
+
+// note: it's caller's responsibility to ensure witnesses.len() = secrets.len()
+fn produce_responses<S>(witnesses: &[Scalar], challenge: &Scalar, secrets: &[S]) -> Vec<Scalar>
+where
+    S: Borrow<Scalar>,
+{
+    debug_assert_eq!(witnesses.len(), secrets.len());
+
+    witnesses
+        .iter()
+        .zip(secrets.iter())
+        .map(|(w, x)| produce_response(w, challenge, x.borrow()))
+        .collect()
+}
+
+impl ProofCmCs {
+    /// Construct non-interactive zero-knowledge proof of correctness of the ciphertexts and the commitment
+    /// using the Fiat-Shamir heuristic.
+    pub(crate) fn construct(
+        params: &Parameters,
+        elgamal_keypair: &ElGamalKeyPair,
+        ephemeral_keys: &[elgamal::EphemeralKey],
+        commitment: &G1Projective,
+        commitment_opening: &Scalar,
+        private_attributes: &[Attribute],
+        priv_attributes_ciphertexts: &[Ciphertext],
+    ) -> Self {
+        // note: this is only called from `prepare_blind_sign` that already checks
+        // whether private attributes are non-empty and whether we don't have too many
+        // attributes in total to sign.
+        // we also know, due to the single call place, that ephemeral_keys.len() == private_attributes.len()
+
+        // witness creation
+
+        let witness_commitment_opening = params.random_scalar();
+        let witness_private_elgamal_key = params.random_scalar();
+        let witness_keys = params.n_random_scalars(ephemeral_keys.len());
+        let witness_attributes = params.n_random_scalars(private_attributes.len());
+
+        // recompute h
+        let h = hash_g1(commitment.to_bytes());
+        let hs_bytes = params
+            .gen_hs()
+            .iter()
+            .map(|h| h.to_bytes())
+            .collect::<Vec<_>>();
+
+        let g1 = params.gen1();
+
+        // compute commitments
+        let commitment_private_key_elgamal = g1 * witness_private_elgamal_key;
+
+        // Aw[i] = (wk[i] * g1)
+        let commitment_keys1_bytes = witness_keys
+            .iter()
+            .map(|wk_i| g1 * wk_i)
+            .map(|witness| witness.to_bytes())
+            .collect::<Vec<_>>();
+
+        // Bw[i] = (wm[i] * h) + (wk[i] * gamma)
+        let commitment_keys2_bytes = witness_keys
+            .iter()
+            .zip(witness_attributes.iter())
+            .map(|(wk_i, wm_i)| elgamal_keypair.public_key() * wk_i + h * wm_i)
+            .map(|witness| witness.to_bytes())
+            .collect::<Vec<_>>();
+
+        // zkp commitment for the attributes commitment cm
+        // Ccm = (wr * g1) + (wm[0] * hs[0]) + ... + (wm[i] * hs[i])
+        let commitment_attributes = g1 * witness_commitment_opening
+            + witness_attributes
+                .iter()
+                .zip(params.gen_hs().iter())
+                .map(|(wm_i, hs_i)| hs_i * wm_i)
+                .sum::<G1Projective>();
+
+        let ciphertexts_bytes = priv_attributes_ciphertexts
+            .iter()
+            .map(|c| c.to_bytes())
+            .collect::<Vec<_>>();
+
+        // compute challenge
+        let challenge = compute_challenge::<ChallengeDigest, _, _>(
+            std::iter::once(params.gen1().to_bytes().as_ref())
+                .chain(hs_bytes.iter().map(|hs| hs.as_ref()))
+                .chain(std::iter::once(h.to_bytes().as_ref()))
+                .chain(std::iter::once(
+                    elgamal_keypair.public_key().to_bytes().as_ref(),
+                ))
+                .chain(std::iter::once(commitment.to_bytes().as_ref()))
+                .chain(std::iter::once(commitment_attributes.to_bytes().as_ref()))
+                .chain(std::iter::once(
+                    commitment_private_key_elgamal.to_bytes().as_ref(),
+                ))
+                .chain(commitment_keys1_bytes.iter().map(|aw| aw.as_ref()))
+                .chain(commitment_keys2_bytes.iter().map(|bw| bw.as_ref()))
+                .chain(ciphertexts_bytes.iter().map(|c| c.as_ref())),
+        );
+
+        // Responses
+        let response_opening =
+            produce_response(&witness_commitment_opening, &challenge, commitment_opening);
+        let response_private_elgamal_key = produce_response(
+            &witness_private_elgamal_key,
+            &challenge,
+            &elgamal_keypair.private_key().0,
+        );
+        let response_keys = produce_responses(&witness_keys, &challenge, ephemeral_keys);
+        let response_attributes = produce_responses(
+            &witness_attributes,
+            &challenge,
+            &private_attributes.iter().collect::<Vec<_>>(),
+        );
+
+        ProofCmCs {
+            challenge,
+            response_opening,
+            response_private_elgamal_key,
+            response_keys,
+            response_attributes,
+        }
+    }
+
+    pub(crate) fn verify(
+        &self,
+        params: &Parameters,
+        pub_key: &elgamal::PublicKey,
+        commitment: &G1Projective,
+        attributes_ciphertexts: &[elgamal::Ciphertext],
+    ) -> bool {
+        if self.response_keys.len() != attributes_ciphertexts.len() {
+            return false;
+        }
+
+        // recompute h
+        let h = hash_g1(commitment.to_bytes());
+        let g1 = params.gen1();
+
+        let hs_bytes = params
+            .gen_hs()
+            .iter()
+            .map(|h| h.to_bytes())
+            .collect::<Vec<_>>();
+
+        // recompute witnesses commitments
+        let commitment_private_key_elgamal =
+            pub_key * &self.challenge + g1 * self.response_private_elgamal_key;
+
+        // Aw[i] = (c * c1[i]) + (rk[i] * g1)
+        let commitment_keys1_bytes = attributes_ciphertexts
+            .iter()
+            .map(|ciphertext| ciphertext.c1())
+            .zip(self.response_keys.iter())
+            .map(|(c1, res_k)| c1 * self.challenge + g1 * res_k)
+            .map(|witness| witness.to_bytes())
+            .collect::<Vec<_>>();
+
+        // Bw[i] = (c * c2[i]) + (rk[i] * gamma) + (rm[i] * h)
+        let commitment_keys2_bytes = izip!(
+            attributes_ciphertexts
+                .iter()
+                .map(|ciphertext| ciphertext.c2()),
+            self.response_keys.iter(),
+            self.response_attributes.iter()
+        )
+        .map(|(c2, res_key, res_attr)| c2 * self.challenge + pub_key * res_key + h * res_attr)
+        .map(|witness| witness.to_bytes())
+        .collect::<Vec<_>>();
+
+        // Cw = (cm * c) + (rr * g1) + (rm[0] * hs[0]) + ... + (rm[n] * hs[n])
+        let commitment_attributes = commitment * self.challenge
+            + g1 * self.response_opening
+            + self
+                .response_attributes
+                .iter()
+                .zip(params.gen_hs().iter())
+                .map(|(res_attr, hs)| hs * res_attr)
+                .sum::<G1Projective>();
+
+        let ciphertexts_bytes = attributes_ciphertexts
+            .iter()
+            .map(|c| c.to_bytes())
+            .collect::<Vec<_>>();
+
+        // re-compute the challenge
+        let challenge = compute_challenge::<ChallengeDigest, _, _>(
+            std::iter::once(params.gen1().to_bytes().as_ref())
+                .chain(hs_bytes.iter().map(|hs| hs.as_ref()))
+                .chain(std::iter::once(h.to_bytes().as_ref()))
+                .chain(std::iter::once(pub_key.to_bytes().as_ref()))
+                .chain(std::iter::once(commitment.to_bytes().as_ref()))
+                .chain(std::iter::once(commitment_attributes.to_bytes().as_ref()))
+                .chain(std::iter::once(
+                    commitment_private_key_elgamal.to_bytes().as_ref(),
+                ))
+                .chain(commitment_keys1_bytes.iter().map(|aw| aw.as_ref()))
+                .chain(commitment_keys2_bytes.iter().map(|bw| bw.as_ref()))
+                .chain(ciphertexts_bytes.iter().map(|c| c.as_ref())),
+        );
+
+        challenge == self.challenge
+    }
+
+    // challenge || response opening || response private elgamal key || keys len || response keys || attributes len || response attributes
+    pub(crate) fn to_bytes(&self) -> Vec<u8> {
+        let keys_len = self.response_keys.len() as u64;
+        let attributes_len = self.response_attributes.len() as u64;
+
+        let mut bytes = Vec::with_capacity(16 + (keys_len + attributes_len + 3) as usize * 32);
+
+        bytes.extend_from_slice(&self.challenge.to_bytes());
+        bytes.extend_from_slice(&self.response_opening.to_bytes());
+        bytes.extend_from_slice(&self.response_private_elgamal_key.to_bytes());
+        bytes.extend_from_slice(&keys_len.to_le_bytes());
+
+        for rk in &self.response_keys {
+            bytes.extend_from_slice(&rk.to_bytes());
+        }
+
+        bytes.extend_from_slice(&attributes_len.to_le_bytes());
+
+        for rm in &self.response_attributes {
+            bytes.extend_from_slice(&rm.to_bytes());
+        }
+
+        bytes
+    }
+
+    pub(crate) fn from_bytes(bytes: &[u8]) -> Result<Self> {
+        // at the very minimum there must be a single attribute being proven
+        if bytes.len() < 32 * 5 + 16 || (bytes.len() - 16) % 32 != 0 {
+            return Err(
+                CoconutError::Deserialization(
+                    "tried to deserialize proof of ciphertexts and commitment with bytes of invalid length".to_string())
+            );
+        }
+
+        let mut idx = 0;
+        let challenge_bytes = bytes[idx..idx + 32].try_into().unwrap();
+        idx += 32;
+        let response_opening_bytes = bytes[idx..idx + 32].try_into().unwrap();
+        idx += 32;
+        let response_private_elgamal_key_bytes = bytes[idx..idx + 32].try_into().unwrap();
+        idx += 32;
+
+        let challenge = try_deserialize_scalar(
+            &challenge_bytes,
+            CoconutError::Deserialization("Failed to deserialize challenge".to_string()),
+        )?;
+        let response_opening = try_deserialize_scalar(
+            &response_opening_bytes,
+            CoconutError::Deserialization(
+                "Failed to deserialize the response to the random".to_string(),
+            ),
+        )?;
+        let response_private_elgamal_key = try_deserialize_scalar(
+            &response_private_elgamal_key_bytes,
+            CoconutError::Deserialization(
+                "Failed to deserialize the response to the private ElGamal key".to_string(),
+            ),
+        )?;
+
+        let rk_len = u64::from_le_bytes(bytes[idx..idx + 8].try_into().unwrap());
+        idx += 8;
+        if bytes[idx..].len() < rk_len as usize * 32 + 8 {
+            return Err(
+                CoconutError::Deserialization(
+                    "tried to deserialize proof of ciphertexts and commitment with insufficient number of bytes provided".to_string()),
+            );
+        }
+
+        let rk_end = idx + rk_len as usize * 32;
+        let response_keys = try_deserialize_scalar_vec(
+            rk_len,
+            &bytes[idx..rk_end],
+            CoconutError::Deserialization("Failed to deserialize keys response".to_string()),
+        )?;
+
+        let rm_len = u64::from_le_bytes(bytes[rk_end..rk_end + 8].try_into().unwrap());
+        let response_attributes = try_deserialize_scalar_vec(
+            rm_len,
+            &bytes[rk_end + 8..],
+            CoconutError::Deserialization("Failed to deserialize attributes response".to_string()),
+        )?;
+
+        Ok(ProofCmCs {
+            challenge,
+            response_opening,
+            response_private_elgamal_key,
+            response_keys,
+            response_attributes,
+        })
+    }
+}
+
+#[derive(Debug)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct ProofKappaZeta {
+    // c
+    challenge: Scalar,
+
+    // responses
+    response_serial_number: Scalar,
+    response_binding_number: Scalar,
+    response_blinder: Scalar,
+}
+
+impl ProofKappaZeta {
+    pub(crate) fn construct(
+        params: &Parameters,
+        verification_key: &VerificationKey,
+        serial_number: &Attribute,
+        binding_number: &Attribute,
+        blinding_factor: &Scalar,
+        blinded_message: &G2Projective,
+        blinded_serial_number: &G2Projective,
+    ) -> Self {
+        // create the witnesses
+        let witness_blinder = params.random_scalar();
+        let witness_serial_number = params.random_scalar();
+        let witness_binding_number = params.random_scalar();
+        let witness_attributes = vec![witness_serial_number, witness_binding_number];
+
+        let beta_bytes = verification_key
+            .beta
+            .iter()
+            .map(|beta_i| beta_i.to_bytes())
+            .collect::<Vec<_>>();
+
+        // witnesses commitments
+        // Aw = g2 * wt + alpha + beta[0] * wm[0] + ... + beta[i] * wm[i]
+        let commitment_kappa = params.gen2() * witness_blinder
+            + verification_key.alpha
+            + witness_attributes
+                .iter()
+                .zip(verification_key.beta.iter())
+                .map(|(wm_i, beta_i)| beta_i * wm_i)
+                .sum::<G2Projective>();
+
+        // zeta is the public value associated with the serial number
+        let commitment_zeta = params.gen2() * witness_serial_number;
+
+        let challenge = compute_challenge::<ChallengeDigest, _, _>(
+            std::iter::once(params.gen2().to_bytes().as_ref())
+                .chain(std::iter::once(blinded_message.to_bytes().as_ref()))
+                .chain(std::iter::once(blinded_serial_number.to_bytes().as_ref()))
+                .chain(std::iter::once(verification_key.alpha.to_bytes().as_ref()))
+                .chain(beta_bytes.iter().map(|b| b.as_ref()))
+                .chain(std::iter::once(commitment_kappa.to_bytes().as_ref()))
+                .chain(std::iter::once(commitment_zeta.to_bytes().as_ref())),
+        );
+
+        // responses
+        let response_blinder = produce_response(&witness_blinder, &challenge, blinding_factor);
+        let response_serial_number =
+            produce_response(&witness_serial_number, &challenge, serial_number);
+        let response_binding_number =
+            produce_response(&witness_binding_number, &challenge, binding_number);
+
+        ProofKappaZeta {
+            challenge,
+            response_serial_number,
+            response_binding_number,
+            response_blinder,
+        }
+    }
+
+    pub(crate) fn private_attributes_len(&self) -> usize {
+        2
+    }
+
+    pub(crate) fn verify(
+        &self,
+        params: &Parameters,
+        verification_key: &VerificationKey,
+        kappa: &G2Projective,
+        zeta: &G2Projective,
+    ) -> bool {
+        let beta_bytes = verification_key
+            .beta
+            .iter()
+            .map(|beta_i| beta_i.to_bytes())
+            .collect::<Vec<_>>();
+
+        let response_attributes = vec![self.response_serial_number, self.response_binding_number];
+        // re-compute witnesses commitments
+        // Aw = (c * kappa) + (rt * g2) + ((1 - c) * alpha) + (rm[0] * beta[0]) + ... + (rm[i] * beta[i])
+        let commitment_kappa = kappa * self.challenge
+            + params.gen2() * self.response_blinder
+            + verification_key.alpha * (Scalar::one() - self.challenge)
+            + response_attributes
+                .iter()
+                .zip(verification_key.beta.iter())
+                .map(|(priv_attr, beta_i)| beta_i * priv_attr)
+                .sum::<G2Projective>();
+
+        // zeta is the public value associated with the serial number
+        let commitment_zeta = zeta * self.challenge + params.gen2() * self.response_serial_number;
+
+        // compute the challenge
+        let challenge = compute_challenge::<ChallengeDigest, _, _>(
+            std::iter::once(params.gen2().to_bytes().as_ref())
+                .chain(std::iter::once(kappa.to_bytes().as_ref()))
+                .chain(std::iter::once(zeta.to_bytes().as_ref()))
+                .chain(std::iter::once(verification_key.alpha.to_bytes().as_ref()))
+                .chain(beta_bytes.iter().map(|b| b.as_ref()))
+                .chain(std::iter::once(commitment_kappa.to_bytes().as_ref()))
+                .chain(std::iter::once(commitment_zeta.to_bytes().as_ref())),
+        );
+
+        challenge == self.challenge
+    }
+
+    // challenge || response serial number || response binding number || repose blinder
+    pub(crate) fn to_bytes(&self) -> Vec<u8> {
+        let attributes_len = 2; // because we have serial number and the binding number
+        let mut bytes = Vec::with_capacity((1 + attributes_len + 1) as usize * 32);
+
+        bytes.extend_from_slice(&self.challenge.to_bytes());
+        bytes.extend_from_slice(&self.response_serial_number.to_bytes());
+        bytes.extend_from_slice(&self.response_binding_number.to_bytes());
+
+        bytes.extend_from_slice(&self.response_blinder.to_bytes());
+
+        bytes
+    }
+
+    pub(crate) fn from_bytes(bytes: &[u8]) -> Result<Self> {
+        // at the very minimum there must be a single attribute being proven
+        if bytes.len() < 32 * 4 || (bytes.len()) % 32 != 0 {
+            return Err(CoconutError::DeserializationInvalidLength {
+                actual: bytes.len(),
+                modulus_target: bytes.len(),
+                modulus: 32,
+                object: "kappa and zeta".to_string(),
+                target: 32 * 4,
+            });
+        }
+
+        let challenge_bytes = bytes[..32].try_into().unwrap();
+        let challenge = try_deserialize_scalar(
+            &challenge_bytes,
+            CoconutError::Deserialization("Failed to deserialize challenge".to_string()),
+        )?;
+
+        let serial_number_bytes = &bytes[32..64].try_into().unwrap();
+        let response_serial_number = try_deserialize_scalar(
+            serial_number_bytes,
+            CoconutError::Deserialization("failed to deserialize the serial number".to_string()),
+        )?;
+
+        let binding_number_bytes = &bytes[64..96].try_into().unwrap();
+        let response_binding_number = try_deserialize_scalar(
+            binding_number_bytes,
+            CoconutError::Deserialization("failed to deserialize the binding number".to_string()),
+        )?;
+
+        let blinder_bytes = bytes[96..].try_into().unwrap();
+        let response_blinder = try_deserialize_scalar(
+            &blinder_bytes,
+            CoconutError::Deserialization("failed to deserialize the blinder".to_string()),
+        )?;
+
+        Ok(ProofKappaZeta {
+            challenge,
+            response_serial_number,
+            response_binding_number,
+            response_blinder,
+        })
+    }
+}
+
+// proof builder:
+// - commitment
+// - challenge
+// - responses
+
+#[cfg(test)]
+mod tests {
+    use group::Group;
+    use rand::thread_rng;
+
+    use crate::scheme::issuance::{compute_attribute_encryption, compute_commitment_hash};
+    use crate::scheme::keygen::keygen;
+    use crate::scheme::setup::setup;
+    use crate::scheme::verification::{compute_kappa, compute_zeta};
+
+    use super::*;
+
+    #[test]
+    fn proof_cm_cs_bytes_roundtrip() {
+        let mut rng = thread_rng();
+        let mut params = setup(1).unwrap();
+
+        let elgamal_keypair = elgamal::elgamal_keygen(&params);
+        let private_attributes = params.n_random_scalars(1);
+
+        // we don't care about 'correctness' of the proof. only whether we can correctly recover it from bytes
+        let cm = G1Projective::random(&mut rng);
+        let r = params.random_scalar();
+
+        let commitment_hash = compute_commitment_hash(cm);
+        let (attributes_ciphertexts, _): (Vec<_>, Vec<_>) = compute_attribute_encryption(
+            &params,
+            private_attributes.as_ref(),
+            elgamal_keypair.public_key(),
+            commitment_hash,
+        );
+        let ephemeral_keys = params.n_random_scalars(1);
+
+        // 0 public 1 private
+        let pi_s = ProofCmCs::construct(
+            &mut params,
+            &elgamal_keypair,
+            &ephemeral_keys,
+            &cm,
+            &r,
+            &private_attributes,
+            &*attributes_ciphertexts,
+        );
+
+        let bytes = pi_s.to_bytes();
+        assert_eq!(ProofCmCs::from_bytes(&bytes).unwrap(), pi_s);
+
+        // 2 private
+        let private_attributes = params.n_random_scalars(2);
+        let ephemeral_keys = params.n_random_scalars(2);
+
+        let pi_s = ProofCmCs::construct(
+            &mut params,
+            &elgamal_keypair,
+            &ephemeral_keys,
+            &cm,
+            &r,
+            &private_attributes,
+            &*attributes_ciphertexts,
+        );
+
+        let bytes = pi_s.to_bytes();
+        assert_eq!(ProofCmCs::from_bytes(&bytes).unwrap(), pi_s);
+    }
+
+    #[test]
+    fn proof_kappa_zeta_bytes_roundtrip() {
+        let mut params = setup(4).unwrap();
+
+        let keypair = keygen(&mut params);
+
+        // we don't care about 'correctness' of the proof. only whether we can correctly recover it from bytes
+        let serial_number = params.random_scalar();
+        let binding_number = params.random_scalar();
+        let private_attributes = vec![serial_number, binding_number];
+
+        let r = params.random_scalar();
+        let kappa = compute_kappa(&params, &keypair.verification_key(), &private_attributes, r);
+        let zeta = compute_zeta(&params, serial_number);
+
+        // 0 public 2 private
+        let pi_v = ProofKappaZeta::construct(
+            &mut params,
+            &keypair.verification_key(),
+            &serial_number,
+            &binding_number,
+            &r,
+            &kappa,
+            &zeta,
+        );
+
+        let proof_bytes = pi_v.to_bytes();
+
+        let proof_from_bytes = ProofKappaZeta::from_bytes(&proof_bytes).unwrap();
+        assert_eq!(proof_from_bytes, pi_v);
+
+        // 2 public 2 private
+        let mut params = setup(4).unwrap();
+        let keypair = keygen(&mut params);
+
+        let pi_v = ProofKappaZeta::construct(
+            &mut params,
+            &keypair.verification_key(),
+            &serial_number,
+            &binding_number,
+            &r,
+            &kappa,
+            &zeta,
+        );
+
+        let proof_bytes = pi_v.to_bytes();
+
+        let proof_from_bytes = ProofKappaZeta::from_bytes(&proof_bytes).unwrap();
+        assert_eq!(proof_from_bytes, pi_v);
+    }
+}

common/nymcoconut/src/scheme/aggregation.rs

@@ -0,0 +1,377 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use core::iter::Sum;
+use core::ops::Mul;
+
+use bls12_381::{G2Prepared, G2Projective, Scalar};
+use group::Curve;
+use itertools::Itertools;
+
+use crate::error::{CoconutError, Result};
+use crate::scheme::verification::check_bilinear_pairing;
+use crate::scheme::{PartialSignature, Signature, SignatureShare, SignerIndex, VerificationKey};
+use crate::utils::perform_lagrangian_interpolation_at_origin;
+use crate::{Attribute, Parameters};
+
+pub(crate) trait Aggregatable: Sized {
+    fn aggregate(aggregatable: &[Self], indices: Option<&[SignerIndex]>) -> Result<Self>;
+
+    fn check_unique_indices(indices: &[SignerIndex]) -> bool {
+        // if aggregation is a threshold one, all indices should be unique
+        indices.iter().unique_by(|&index| index).count() == indices.len()
+    }
+}
+
+// includes `VerificationKey`
+impl<T> Aggregatable for T
+where
+    T: Sum,
+    for<'a> T: Sum<&'a T>,
+    for<'a> &'a T: Mul<Scalar, Output = T>,
+{
+    fn aggregate(aggregatable: &[T], indices: Option<&[u64]>) -> Result<T> {
+        if aggregatable.is_empty() {
+            return Err(CoconutError::Aggregation("Empty set of values".to_string()));
+        }
+
+        if let Some(indices) = indices {
+            if !Self::check_unique_indices(indices) {
+                return Err(CoconutError::Aggregation("Non-unique indices".to_string()));
+            }
+            perform_lagrangian_interpolation_at_origin(indices, aggregatable)
+        } else {
+            // non-threshold
+            Ok(aggregatable.iter().sum())
+        }
+    }
+}
+
+impl Aggregatable for PartialSignature {
+    fn aggregate(sigs: &[PartialSignature], indices: Option<&[u64]>) -> Result<Signature> {
+        let h = sigs
+            .get(0)
+            .ok_or_else(|| CoconutError::Aggregation("Empty set of signatures".to_string()))?
+            .sig1();
+
+        // TODO: is it possible to avoid this allocation?
+        let sigmas = sigs.iter().map(|sig| *sig.sig2()).collect::<Vec<_>>();
+        let aggr_sigma = Aggregatable::aggregate(&sigmas, indices)?;
+
+        Ok(Signature(*h, aggr_sigma))
+    }
+}
+
+/// Ensures all provided verification keys were generated to verify the same number of attributes.
+fn check_same_key_size(keys: &[VerificationKey]) -> bool {
+    keys.iter().map(|vk| vk.beta.len()).all_equal()
+}
+
+pub fn aggregate_verification_keys(
+    keys: &[VerificationKey],
+    indices: Option<&[SignerIndex]>,
+) -> Result<VerificationKey> {
+    if !check_same_key_size(keys) {
+        return Err(CoconutError::Aggregation(
+            "Verification keys are of different sizes".to_string(),
+        ));
+    }
+    Aggregatable::aggregate(keys, indices)
+}
+
+pub fn aggregate_signatures(
+    params: &Parameters,
+    verification_key: &VerificationKey,
+    attributes: &[Attribute],
+    signatures: &[PartialSignature],
+    indices: Option<&[SignerIndex]>,
+) -> Result<Signature> {
+    // aggregate the signature
+
+    let signature = match Aggregatable::aggregate(signatures, indices) {
+        Ok(res) => res,
+        Err(err) => return Err(err),
+    };
+
+    // Verify the signature
+    let alpha = verification_key.alpha;
+
+    let tmp = attributes
+        .iter()
+        .zip(verification_key.beta.iter())
+        .map(|(attr, beta_i)| beta_i * attr)
+        .sum::<G2Projective>();
+
+    if !check_bilinear_pairing(
+        &signature.0.to_affine(),
+        &G2Prepared::from((alpha + tmp).to_affine()),
+        &signature.1.to_affine(),
+        params.prepared_miller_g2(),
+    ) {
+        return Err(CoconutError::Aggregation(
+            "Verification of the aggregated signature failed".to_string(),
+        ));
+    }
+    Ok(signature)
+}
+
+pub fn aggregate_signature_shares(
+    params: &Parameters,
+    verification_key: &VerificationKey,
+    attributes: &[Attribute],
+    shares: &[SignatureShare],
+) -> Result<Signature> {
+    let (signatures, indices): (Vec<_>, Vec<_>) = shares
+        .iter()
+        .map(|share| (*share.signature(), share.index()))
+        .unzip();
+
+    aggregate_signatures(
+        params,
+        verification_key,
+        attributes,
+        &signatures,
+        Some(&indices),
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use bls12_381::G1Projective;
+    use group::Group;
+
+    use crate::scheme::issuance::sign;
+    use crate::scheme::keygen::ttp_keygen;
+    use crate::scheme::setup::Parameters;
+    use crate::scheme::verification::verify;
+
+    use super::*;
+
+    #[test]
+    fn key_aggregation_works_for_any_subset_of_keys() {
+        let mut params = Parameters::new(2).unwrap();
+        let keypairs = ttp_keygen(&mut params, 3, 5).unwrap();
+
+        let vks = keypairs
+            .into_iter()
+            .map(|keypair| keypair.verification_key())
+            .collect::<Vec<_>>();
+
+        let aggr_vk1 = aggregate_verification_keys(&vks[..3], Some(&[1, 2, 3])).unwrap();
+        let aggr_vk2 = aggregate_verification_keys(&vks[2..], Some(&[3, 4, 5])).unwrap();
+
+        assert_eq!(aggr_vk1, aggr_vk2);
+
+        // TODO: should those two actually work or not?
+        // aggregating threshold+1
+        let aggr_more = aggregate_verification_keys(&vks[1..], Some(&[2, 3, 4, 5])).unwrap();
+        assert_eq!(aggr_vk1, aggr_more);
+
+        // aggregating all
+        let aggr_all = aggregate_verification_keys(&vks, Some(&[1, 2, 3, 4, 5])).unwrap();
+        assert_eq!(aggr_all, aggr_vk1);
+
+        // not taking enough points (threshold was 3)
+        let aggr_not_enough = aggregate_verification_keys(&vks[..2], Some(&[1, 2])).unwrap();
+        assert_ne!(aggr_not_enough, aggr_vk1);
+
+        // taking wrong index
+        let aggr_bad = aggregate_verification_keys(&vks[2..], Some(&[42, 123, 100])).unwrap();
+        assert_ne!(aggr_vk1, aggr_bad);
+    }
+
+    #[test]
+    fn key_aggregation_doesnt_work_for_empty_set_of_keys() {
+        let keys: Vec<VerificationKey> = vec![];
+        assert!(aggregate_verification_keys(&keys, None).is_err());
+    }
+
+    #[test]
+    fn key_aggregation_doesnt_work_if_indices_have_invalid_length() {
+        let keys = vec![VerificationKey::identity(3)];
+
+        assert!(aggregate_verification_keys(&keys, Some(&[])).is_err());
+        assert!(aggregate_verification_keys(&keys, Some(&[1, 2])).is_err());
+    }
+
+    #[test]
+    fn key_aggregation_doesnt_work_for_non_unique_indices() {
+        let keys = vec![VerificationKey::identity(3), VerificationKey::identity(3)];
+
+        assert!(aggregate_verification_keys(&keys, Some(&[1, 1])).is_err());
+    }
+
+    #[test]
+    fn key_aggregation_doesnt_work_for_keys_of_different_size() {
+        let keys = vec![VerificationKey::identity(3), VerificationKey::identity(1)];
+
+        assert!(aggregate_verification_keys(&keys, None).is_err())
+    }
+
+    #[test]
+    fn signature_aggregation_works_for_any_subset_of_signatures() {
+        let mut params = Parameters::new(2).unwrap();
+        let attributes = params.n_random_scalars(2);
+
+        let keypairs = ttp_keygen(&mut params, 3, 5).unwrap();
+
+        let (sks, vks): (Vec<_>, Vec<_>) = keypairs
+            .into_iter()
+            .map(|keypair| (keypair.secret_key(), keypair.verification_key()))
+            .unzip();
+
+        let sigs = sks
+            .iter()
+            .map(|sk| sign(&mut params, sk, &attributes).unwrap())
+            .collect::<Vec<_>>();
+
+        // aggregating (any) threshold works
+        let aggr_vk_1 = aggregate_verification_keys(&vks[..3], Some(&[1, 2, 3])).unwrap();
+        let aggr_sig1 = aggregate_signatures(
+            &params,
+            &aggr_vk_1,
+            &attributes,
+            &sigs[..3],
+            Some(&[1, 2, 3]),
+        )
+        .unwrap();
+
+        let aggr_vk_2 = aggregate_verification_keys(&vks[2..], Some(&[3, 4, 5])).unwrap();
+        let aggr_sig2 = aggregate_signatures(
+            &params,
+            &aggr_vk_1,
+            &attributes,
+            &sigs[2..],
+            Some(&[3, 4, 5]),
+        )
+        .unwrap();
+        assert_eq!(aggr_sig1, aggr_sig2);
+
+        // verify credential for good measure
+        assert!(verify(&params, &aggr_vk_1, &attributes, &aggr_sig1));
+        assert!(verify(&params, &aggr_vk_2, &attributes, &aggr_sig2));
+
+        // aggregating threshold+1 works
+        let aggr_vk_more = aggregate_verification_keys(&vks[1..], Some(&[2, 3, 4, 5])).unwrap();
+        let aggr_more = aggregate_signatures(
+            &params,
+            &aggr_vk_more,
+            &attributes,
+            &sigs[1..],
+            Some(&[2, 3, 4, 5]),
+        )
+        .unwrap();
+        assert_eq!(aggr_sig1, aggr_more);
+
+        // aggregating all
+        let aggr_vk_all = aggregate_verification_keys(&vks, Some(&[1, 2, 3, 4, 5])).unwrap();
+        let aggr_all = aggregate_signatures(
+            &params,
+            &aggr_vk_all,
+            &attributes,
+            &sigs,
+            Some(&[1, 2, 3, 4, 5]),
+        )
+        .unwrap();
+        assert_eq!(aggr_all, aggr_sig1);
+
+        // not taking enough points (threshold was 3) should fail
+        let aggr_vk_not_enough = aggregate_verification_keys(&vks[..2], Some(&[1, 2])).unwrap();
+        let aggr_not_enough = aggregate_signatures(
+            &params,
+            &aggr_vk_not_enough,
+            &attributes,
+            &sigs[..2],
+            Some(&[1, 2]),
+        )
+        .unwrap();
+        assert_ne!(aggr_not_enough, aggr_sig1);
+
+        // taking wrong index should fail
+        let aggr_vk_bad = aggregate_verification_keys(&vks[2..], Some(&[1, 2, 3])).unwrap();
+        assert!(aggregate_signatures(
+            &params,
+            &aggr_vk_bad,
+            &attributes,
+            &sigs[2..],
+            Some(&[42, 123, 100]),
+        )
+        .is_err());
+    }
+
+    fn random_signature() -> Signature {
+        let mut rng = rand::thread_rng();
+        Signature(
+            G1Projective::random(&mut rng),
+            G1Projective::random(&mut rng),
+        )
+    }
+
+    #[test]
+    fn signature_aggregation_doesnt_work_for_empty_set_of_signatures() {
+        let signatures: Vec<Signature> = vec![];
+        let mut params = Parameters::new(2).unwrap();
+        let attributes = params.n_random_scalars(2);
+        let keypairs = ttp_keygen(&mut params, 3, 5).unwrap();
+
+        let (_, vks): (Vec<_>, Vec<_>) = keypairs
+            .into_iter()
+            .map(|keypair| (keypair.secret_key(), keypair.verification_key()))
+            .unzip();
+
+        let aggr_vk_all = aggregate_verification_keys(&vks, None).unwrap();
+        assert!(
+            aggregate_signatures(&params, &aggr_vk_all, &attributes, &signatures, None).is_err()
+        );
+    }
+
+    #[test]
+    fn signature_aggregation_doesnt_work_if_indices_have_invalid_length() {
+        let signatures = vec![random_signature()];
+        let mut params = Parameters::new(2).unwrap();
+        let attributes = params.n_random_scalars(2);
+        let keypairs = ttp_keygen(&mut params, 3, 5).unwrap();
+        let (_, vks): (Vec<_>, Vec<_>) = keypairs
+            .into_iter()
+            .map(|keypair| (keypair.secret_key(), keypair.verification_key()))
+            .unzip();
+        let aggr_vk_all = aggregate_verification_keys(&vks, None).unwrap();
+
+        assert!(
+            aggregate_signatures(&params, &aggr_vk_all, &attributes, &signatures, Some(&[]))
+                .is_err()
+        );
+        assert!(aggregate_signatures(
+            &params,
+            &aggr_vk_all,
+            &attributes,
+            &signatures,
+            Some(&[1, 2]),
+        )
+        .is_err());
+    }
+
+    #[test]
+    fn signature_aggregation_doesnt_work_for_non_unique_indices() {
+        let signatures = vec![random_signature(), random_signature()];
+        let mut params = Parameters::new(2).unwrap();
+        let attributes = params.n_random_scalars(2);
+        let keypairs = ttp_keygen(&mut params, 3, 5).unwrap();
+        let (_, vks): (Vec<_>, Vec<_>) = keypairs
+            .into_iter()
+            .map(|keypair| (keypair.secret_key(), keypair.verification_key()))
+            .unzip();
+        let aggr_vk_all = aggregate_verification_keys(&vks, None).unwrap();
+
+        assert!(aggregate_signatures(
+            &params,
+            &aggr_vk_all,
+            &attributes,
+            &signatures,
+            Some(&[1, 1]),
+        )
+        .is_err());
+    }
+
+    // TODO: test for aggregating non-threshold keys
+}

common/nymcoconut/src/scheme/issuance.rs

@@ -0,0 +1,382 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use std::convert::TryFrom;
+use std::convert::TryInto;
+
+use bls12_381::{G1Affine, G1Projective, Scalar};
+use group::{Curve, GroupEncoding};
+
+use crate::elgamal::{Ciphertext, EphemeralKey};
+use crate::error::{CoconutError, Result};
+use crate::proofs::ProofCmCs;
+use crate::scheme::setup::Parameters;
+use crate::scheme::BlindedSignature;
+use crate::scheme::SecretKey;
+/// Creates a Coconut Signature under a given secret key on a set of public attributes only.
+#[cfg(test)]
+use crate::Signature;
+use crate::{elgamal, Attribute, ElGamalKeyPair};
+// TODO: possibly completely remove those two functions.
+// They only exist to have a simpler and smaller code snippets to test
+// basic functionalities.
+use crate::traits::{Base58, Bytable};
+use crate::utils::{hash_g1, try_deserialize_g1_projective};
+
+// TODO NAMING: double check this one
+// Lambda
+#[derive(Debug)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct BlindSignRequest {
+    // cm
+    commitment: G1Projective,
+    // h
+    commitment_hash: G1Projective,
+    // c
+    private_attributes_ciphertexts: Vec<elgamal::Ciphertext>,
+    // pi_s
+    pi_s: ProofCmCs,
+}
+
+impl TryFrom<&[u8]> for BlindSignRequest {
+    type Error = CoconutError;
+
+    fn try_from(bytes: &[u8]) -> Result<BlindSignRequest> {
+        if bytes.len() < 48 + 48 + 8 + 96 {
+            return Err(CoconutError::DeserializationMinLength {
+                min: 48 + 48 + 8 + 96,
+                actual: bytes.len(),
+            });
+        }
+
+        let mut j = 0;
+        let commitment_bytes_len = 48;
+        let commitment_hash_bytes_len = 48;
+
+        let cm_bytes = bytes[..j + commitment_bytes_len].try_into().unwrap();
+        let commitment = try_deserialize_g1_projective(
+            &cm_bytes,
+            CoconutError::Deserialization(
+                "Failed to deserialize compressed commitment".to_string(),
+            ),
+        )?;
+        j += commitment_bytes_len;
+
+        let cm_hash_bytes = bytes[j..j + commitment_hash_bytes_len].try_into().unwrap();
+        let commitment_hash = try_deserialize_g1_projective(
+            &cm_hash_bytes,
+            CoconutError::Deserialization(
+                "Failed to deserialize compressed commitment hash".to_string(),
+            ),
+        )?;
+        j += commitment_hash_bytes_len;
+
+        let c_len = u64::from_le_bytes(bytes[j..j + 8].try_into().unwrap());
+        j += 8;
+        if bytes[j..].len() < c_len as usize * 96 {
+            return Err(CoconutError::DeserializationMinLength {
+                min: c_len as usize * 96,
+                actual: bytes[56..].len(),
+            });
+        }
+
+        let mut private_attributes_ciphertexts = Vec::with_capacity(c_len as usize);
+        for i in 0..c_len as usize {
+            let start = j + i * 96;
+            let end = start + 96;
+            private_attributes_ciphertexts.push(Ciphertext::try_from(&bytes[start..end])?)
+        }
+
+        let pi_s = ProofCmCs::from_bytes(&bytes[j + c_len as usize * 96..])?;
+
+        Ok(BlindSignRequest {
+            commitment,
+            commitment_hash,
+            private_attributes_ciphertexts,
+            pi_s,
+        })
+    }
+}
+
+impl Bytable for BlindSignRequest {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        let cm_bytes = self.commitment.to_affine().to_compressed();
+        let cm_hash_bytes = self.commitment_hash.to_affine().to_compressed();
+        let c_len = self.private_attributes_ciphertexts.len() as u64;
+        let proof_bytes = self.pi_s.to_bytes();
+
+        let mut bytes = Vec::with_capacity(48 + 48 + 8 + c_len as usize * 96 + proof_bytes.len());
+
+        bytes.extend_from_slice(&cm_bytes);
+        bytes.extend_from_slice(&cm_hash_bytes);
+        bytes.extend_from_slice(&c_len.to_le_bytes());
+        for c in &self.private_attributes_ciphertexts {
+            bytes.extend_from_slice(&c.to_bytes());
+        }
+
+        bytes.extend_from_slice(&proof_bytes);
+
+        bytes
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self> {
+        BlindSignRequest::from_bytes(slice)
+    }
+}
+
+impl Base58 for BlindSignRequest {}
+
+impl BlindSignRequest {
+    fn verify_proof(&self, params: &Parameters, pub_key: &elgamal::PublicKey) -> bool {
+        self.pi_s.verify(
+            params,
+            pub_key,
+            &self.commitment,
+            &self.private_attributes_ciphertexts,
+        )
+    }
+
+    pub fn get_commitment_hash(&self) -> G1Projective {
+        self.commitment_hash
+    }
+
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.to_byte_vec()
+    }
+
+    pub fn from_bytes(bytes: &[u8]) -> Result<BlindSignRequest> {
+        BlindSignRequest::try_from(bytes)
+    }
+}
+
+pub fn compute_private_attributes_commitment(
+    params: &Parameters,
+    private_attributes: &[Attribute],
+    hs: &[G1Affine],
+) -> (Scalar, G1Projective) {
+    let commitment_opening = params.random_scalar();
+
+    // Produces h0 ^ m0 * h1^m1 * .... * hn^mn
+    // where m0, m1, ...., mn are private attributes
+    let attr_cm = private_attributes
+        .iter()
+        .zip(hs)
+        .map(|(&m, h)| h * m)
+        .sum::<G1Projective>();
+
+    // Produces g1^r * h0 ^ m0 * h1^m1 * .... * hn^mn
+    let commitment = params.gen1() * commitment_opening + attr_cm;
+    (commitment_opening, commitment)
+}
+
+pub fn compute_commitment_hash(commitment: G1Projective) -> G1Projective {
+    hash_g1(commitment.to_bytes())
+}
+
+pub fn compute_attribute_encryption(
+    params: &Parameters,
+    private_attributes: &[Attribute],
+    pub_key: &elgamal::PublicKey,
+    commitment_hash: G1Projective,
+) -> (Vec<Ciphertext>, Vec<EphemeralKey>) {
+    private_attributes
+        .iter()
+        .map(|m| pub_key.encrypt(params, &commitment_hash, m))
+        .unzip()
+}
+
+/// Builds cryptographic material required for blind sign.
+pub fn prepare_blind_sign(
+    params: &Parameters,
+    elgamal_keypair: &ElGamalKeyPair,
+    private_attributes: &[Attribute],
+    public_attributes: &[Attribute],
+) -> Result<BlindSignRequest> {
+    if private_attributes.is_empty() {
+        return Err(CoconutError::Issuance(
+            "Tried to prepare blind sign request for an empty set of private attributes"
+                .to_string(),
+        ));
+    }
+
+    let hs = params.gen_hs();
+    if private_attributes.len() + public_attributes.len() > hs.len() {
+        return Err(CoconutError::IssuanceMaxAttributes {
+            max: hs.len(),
+            requested: private_attributes.len() + public_attributes.len(),
+        });
+    }
+
+    let (commitment_opening, commitment) =
+        compute_private_attributes_commitment(params, private_attributes, hs);
+
+    // Compute the challenge as the commitment hash
+    let commitment_hash = compute_commitment_hash(commitment);
+    // build ElGamal encryption
+    let (private_attributes_ciphertexts, ephemeral_keys): (Vec<_>, Vec<_>) =
+        compute_attribute_encryption(
+            params,
+            private_attributes,
+            elgamal_keypair.public_key(),
+            commitment_hash,
+        );
+
+    let pi_s = ProofCmCs::construct(
+        params,
+        elgamal_keypair,
+        &ephemeral_keys,
+        &commitment,
+        &commitment_opening,
+        private_attributes,
+        &*private_attributes_ciphertexts,
+    );
+
+    Ok(BlindSignRequest {
+        commitment,
+        commitment_hash,
+        private_attributes_ciphertexts,
+        pi_s,
+    })
+}
+
+pub fn blind_sign(
+    params: &Parameters,
+    signing_secret_key: &SecretKey,
+    prover_pub_key: &elgamal::PublicKey,
+    blind_sign_request: &BlindSignRequest,
+    public_attributes: &[Attribute],
+) -> Result<BlindedSignature> {
+    let num_private = blind_sign_request.private_attributes_ciphertexts.len();
+    let hs = params.gen_hs();
+
+    if num_private + public_attributes.len() > hs.len() {
+        return Err(CoconutError::IssuanceMaxAttributes {
+            max: hs.len(),
+            requested: num_private + public_attributes.len(),
+        });
+    }
+
+    // Verify the commitment hash
+    let h = hash_g1(blind_sign_request.commitment.to_bytes());
+    if !(h == blind_sign_request.commitment_hash) {
+        return Err(CoconutError::Issuance(
+            "Failed to verify the commitment hash".to_string(),
+        ));
+    }
+
+    // Verify the ZK proof
+    if !blind_sign_request.verify_proof(params, prover_pub_key) {
+        return Err(CoconutError::Issuance(
+            "Failed to verify the proof of knowledge".to_string(),
+        ));
+    }
+
+    // in python implementation there are n^2 G1 multiplications, let's do it with a single one instead.
+    // i.e. compute h ^ (pub_m[0] * y[m + 1] + ... + pub_m[n] * y[m + n]) directly (where m is number of PRIVATE attributes)
+    // rather than ((h ^ pub_m[0]) ^ y[m + 1] , (h ^ pub_m[1]) ^ y[m + 2] , ...).sum() separately
+    let signed_public = h * public_attributes
+        .iter()
+        .zip(signing_secret_key.ys.iter().skip(num_private))
+        .map(|(attr, yi)| attr * yi)
+        .sum::<Scalar>();
+
+    // c1[0] ^ y[0] * ... * c1[m] ^ y[m]
+    let sig_1 = blind_sign_request
+        .private_attributes_ciphertexts
+        .iter()
+        .map(|ciphertext| ciphertext.c1())
+        .zip(signing_secret_key.ys.iter())
+        .map(|(c1, yi)| c1 * yi)
+        .sum();
+
+    // h ^ x + c2[0] ^ y[0] + ... c2[m] ^ y[m] + h ^ (pub_m[0] * y[m + 1] + ... + pub_m[n] * y[m + n])
+    let sig_2 = blind_sign_request
+        .private_attributes_ciphertexts
+        .iter()
+        .map(|ciphertext| ciphertext.c2())
+        .zip(signing_secret_key.ys.iter())
+        .map(|(c2, yi)| c2 * yi)
+        .chain(std::iter::once(h * signing_secret_key.x))
+        .chain(std::iter::once(signed_public))
+        .sum();
+
+    Ok(BlindedSignature(h, elgamal::Ciphertext(sig_1, sig_2)))
+}
+
+#[cfg(test)]
+pub fn sign(
+    params: &mut Parameters,
+    secret_key: &SecretKey,
+    public_attributes: &[Attribute],
+) -> Result<Signature> {
+    if public_attributes.len() > secret_key.ys.len() {
+        return Err(CoconutError::IssuanceMaxAttributes {
+            max: secret_key.ys.len(),
+            requested: public_attributes.len(),
+        });
+    }
+
+    // TODO: why in the python implementation this hash onto the curve is present
+    // while it's not used in the paper? the paper uses random exponent instead.
+    // (the python implementation hashes string representation of all attributes onto the curve,
+    // but I think the same can be achieved by just summing the attributes thus avoiding the unnecessary
+    // transformation. If I'm wrong, please correct me.)
+    let attributes_sum = public_attributes.iter().sum::<Scalar>();
+    let h = hash_g1((params.gen1() * attributes_sum).to_bytes());
+
+    // x + m0 * y0 + m1 * y1 + ... mn * yn
+    let exponent = secret_key.x
+        + public_attributes
+            .iter()
+            .zip(secret_key.ys.iter())
+            .map(|(m_i, y_i)| m_i * y_i)
+            .sum::<Scalar>();
+
+    let sig2 = h * exponent;
+    Ok(Signature(h, sig2))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn blind_sign_request_bytes_roundtrip() {
+        let mut params = Parameters::new(1).unwrap();
+        let public_attributes = params.n_random_scalars(0);
+        let private_attributes = params.n_random_scalars(1);
+        let elgamal_keypair = elgamal::elgamal_keygen(&params);
+
+        let lambda = prepare_blind_sign(
+            &mut params,
+            &elgamal_keypair,
+            &private_attributes,
+            &public_attributes,
+        )
+        .unwrap();
+
+        let bytes = lambda.to_bytes();
+        println!("{:?}", bytes.len());
+        assert_eq!(
+            BlindSignRequest::try_from(bytes.as_slice()).unwrap(),
+            lambda
+        );
+
+        let mut params = Parameters::new(4).unwrap();
+        let public_attributes = params.n_random_scalars(2);
+        let private_attributes = params.n_random_scalars(2);
+        let lambda = prepare_blind_sign(
+            &mut params,
+            &elgamal_keypair,
+            &private_attributes,
+            &public_attributes,
+        )
+        .unwrap();
+
+        let bytes = lambda.to_bytes();
+        assert_eq!(
+            BlindSignRequest::try_from(bytes.as_slice()).unwrap(),
+            lambda
+        );
+    }
+}

common/nymcoconut/src/scheme/keygen.rs

@@ -0,0 +1,539 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use core::borrow::Borrow;
+use core::iter::Sum;
+use core::ops::{Add, Mul};
+use std::convert::TryFrom;
+use std::convert::TryInto;
+
+use bls12_381::{G2Projective, Scalar};
+use group::Curve;
+use serde_derive::{Deserialize, Serialize};
+
+use crate::error::{CoconutError, Result};
+use crate::scheme::aggregation::aggregate_verification_keys;
+use crate::scheme::setup::Parameters;
+use crate::scheme::SignerIndex;
+use crate::traits::Bytable;
+use crate::utils::{
+    try_deserialize_g2_projective, try_deserialize_scalar, try_deserialize_scalar_vec, Polynomial,
+};
+use crate::Base58;
+
+#[derive(Debug, Clone)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct SecretKey {
+    pub(crate) x: Scalar,
+    pub(crate) ys: Vec<Scalar>,
+}
+
+impl TryFrom<&[u8]> for SecretKey {
+    type Error = CoconutError;
+
+    fn try_from(bytes: &[u8]) -> Result<SecretKey> {
+        if bytes.len() < 32 * 2 + 8 || (bytes.len() - 8) % 32 != 0 {
+            return Err(CoconutError::DeserializationInvalidLength {
+                actual: bytes.len(),
+                modulus_target: bytes.len() - 8,
+                target: 32 * 2 + 8,
+                modulus: 32,
+                object: "secret key".to_string(),
+            });
+        }
+
+        // this conversion will not fail as we are taking the same length of data
+        let x_bytes: [u8; 32] = bytes[..32].try_into().unwrap();
+        let ys_len = u64::from_le_bytes(bytes[32..40].try_into().unwrap());
+        let actual_ys_len = (bytes.len() - 40) / 32;
+
+        if ys_len as usize != actual_ys_len {
+            return Err(CoconutError::Deserialization(format!(
+                "Tried to deserialize secret key with inconsistent ys len (expected {}, got {})",
+                ys_len, actual_ys_len
+            )));
+        }
+
+        let x = try_deserialize_scalar(
+            &x_bytes,
+            CoconutError::Deserialization("Failed to deserialize secret key scalar".to_string()),
+        )?;
+        let ys = try_deserialize_scalar_vec(
+            ys_len,
+            &bytes[40..],
+            CoconutError::Deserialization("Failed to deserialize secret key scalars".to_string()),
+        )?;
+
+        Ok(SecretKey { x, ys })
+    }
+}
+
+impl SecretKey {
+    /// Derive verification key using this secret key.
+    pub fn verification_key(&self, params: &Parameters) -> VerificationKey {
+        let g2 = params.gen2();
+        VerificationKey {
+            alpha: g2 * self.x,
+            beta: self.ys.iter().map(|y| g2 * y).collect(),
+        }
+    }
+
+    // x || ys.len() || ys
+    pub fn to_bytes(&self) -> Vec<u8> {
+        let ys_len = self.ys.len() as u64;
+        let mut bytes = Vec::with_capacity(8 + (ys_len + 1) as usize * 32);
+
+        bytes.extend_from_slice(&self.x.to_bytes());
+        bytes.extend_from_slice(&ys_len.to_le_bytes());
+        for y in self.ys.iter() {
+            bytes.extend_from_slice(&y.to_bytes())
+        }
+        bytes
+    }
+
+    pub fn from_bytes(bytes: &[u8]) -> Result<SecretKey> {
+        SecretKey::try_from(bytes)
+    }
+}
+
+impl Bytable for SecretKey {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        self.to_bytes()
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self> {
+        SecretKey::try_from(slice)
+    }
+}
+
+impl Base58 for SecretKey {}
+
+// TODO: perhaps change points to affine representation
+// to make verification slightly more efficient?
+#[derive(Debug, PartialEq, Clone)]
+pub struct VerificationKey {
+    // TODO add gen2 as per the paper or imply it from the fact library is using bls381?
+    pub(crate) alpha: G2Projective,
+    pub(crate) beta: Vec<G2Projective>,
+}
+
+impl TryFrom<&[u8]> for VerificationKey {
+    type Error = CoconutError;
+
+    fn try_from(bytes: &[u8]) -> Result<VerificationKey> {
+        if bytes.len() < 96 * 2 + 8 || (bytes.len() - 8) % 96 != 0 {
+            return Err(CoconutError::DeserializationInvalidLength {
+                actual: bytes.len(),
+                modulus_target: bytes.len() - 8,
+                target: 96 * 2 + 8,
+                modulus: 96,
+                object: "secret key".to_string(),
+            });
+        }
+
+        // this conversion will not fail as we are taking the same length of data
+        let alpha_bytes: [u8; 96] = bytes[..96].try_into().unwrap();
+        let beta_len = u64::from_le_bytes(bytes[96..104].try_into().unwrap());
+        let actual_beta_len = (bytes.len() - 104) / 96;
+
+        if beta_len as usize != actual_beta_len {
+            return Err(
+                CoconutError::Deserialization(
+                    format!("Tried to deserialize verification key with inconsistent beta len (expected {}, got {})",
+                            beta_len, actual_beta_len
+                    )));
+        }
+
+        let alpha = try_deserialize_g2_projective(
+            &alpha_bytes,
+            CoconutError::Deserialization(
+                "Failed to deserialize verification key G2 point (alpha)".to_string(),
+            ),
+        )?;
+
+        let mut beta = Vec::with_capacity(actual_beta_len);
+        for i in 0..actual_beta_len {
+            let start = 104 + i * 96;
+            let end = start + 96;
+            let beta_i_bytes = bytes[start..end].try_into().unwrap();
+            let beta_i = try_deserialize_g2_projective(
+                &beta_i_bytes,
+                CoconutError::Deserialization(
+                    "Failed to deserialize verification key G2 point (beta)".to_string(),
+                ),
+            )?;
+
+            beta.push(beta_i)
+        }
+
+        Ok(VerificationKey { alpha, beta })
+    }
+}
+
+impl<'b> Add<&'b VerificationKey> for VerificationKey {
+    type Output = VerificationKey;
+
+    #[inline]
+    fn add(self, rhs: &'b VerificationKey) -> VerificationKey {
+        // If you're trying to add two keys together that were created
+        // for different number of attributes, just panic as it's a
+        // nonsense operation.
+        assert_eq!(
+            self.beta.len(),
+            rhs.beta.len(),
+            "trying to add verification keys generated for different number of attributes"
+        );
+
+        VerificationKey {
+            alpha: self.alpha + rhs.alpha,
+            beta: self
+                .beta
+                .iter()
+                .zip(rhs.beta.iter())
+                .map(|(self_beta, rhs_beta)| self_beta + rhs_beta)
+                .collect(),
+        }
+    }
+}
+
+impl<'a> Mul<Scalar> for &'a VerificationKey {
+    type Output = VerificationKey;
+
+    #[inline]
+    fn mul(self, rhs: Scalar) -> Self::Output {
+        VerificationKey {
+            alpha: self.alpha * rhs,
+            beta: self.beta.iter().map(|b_i| b_i * rhs).collect(),
+        }
+    }
+}
+
+impl<T> Sum<T> for VerificationKey
+where
+    T: Borrow<VerificationKey>,
+{
+    #[inline]
+    fn sum<I>(iter: I) -> Self
+    where
+        I: Iterator<Item = T>,
+    {
+        let mut peekable = iter.peekable();
+        let head_attributes = match peekable.peek() {
+            Some(head) => head.borrow().beta.len(),
+            None => {
+                // TODO: this is a really weird edge case. You're trying to sum an EMPTY iterator
+                // of VerificationKey. So should it panic here or just return some nonsense value?
+                return VerificationKey::identity(0);
+            }
+        };
+
+        peekable.fold(VerificationKey::identity(head_attributes), |acc, item| {
+            acc + item.borrow()
+        })
+    }
+}
+
+impl VerificationKey {
+    /// Create a (kinda) identity verification key using specified
+    /// number of 'beta' elements
+    pub(crate) fn identity(beta_size: usize) -> Self {
+        VerificationKey {
+            alpha: G2Projective::identity(),
+            beta: vec![G2Projective::identity(); beta_size],
+        }
+    }
+
+    pub fn aggregate(sigs: &[Self], indices: Option<&[SignerIndex]>) -> Result<Self> {
+        aggregate_verification_keys(sigs, indices)
+    }
+
+    pub fn alpha(&self) -> &G2Projective {
+        &self.alpha
+    }
+
+    pub fn beta(&self) -> &Vec<G2Projective> {
+        &self.beta
+    }
+
+    pub fn to_bytes(&self) -> Vec<u8> {
+        let beta_len = self.beta.len() as u64;
+        let mut bytes = Vec::with_capacity(8 + (beta_len + 1) as usize * 96);
+
+        bytes.extend_from_slice(&self.alpha.to_affine().to_compressed());
+        bytes.extend_from_slice(&beta_len.to_le_bytes());
+        for beta in self.beta.iter() {
+            bytes.extend_from_slice(&beta.to_affine().to_compressed())
+        }
+        bytes
+    }
+
+    pub fn from_bytes(bytes: &[u8]) -> Result<VerificationKey> {
+        VerificationKey::try_from(bytes)
+    }
+}
+
+impl Bytable for VerificationKey {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        self.to_bytes()
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self> {
+        VerificationKey::try_from(slice)
+    }
+}
+
+impl Base58 for VerificationKey {}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct KeyPair {
+    secret_key: SecretKey,
+    verification_key: VerificationKey,
+
+    /// Optional index value specifying polynomial point used during threshold key generation.
+    pub index: Option<SignerIndex>,
+}
+
+impl KeyPair {
+    const MARKER_BYTES: &'static [u8] = b"coconutkeypair";
+
+    pub fn secret_key(&self) -> SecretKey {
+        self.secret_key.clone()
+    }
+
+    pub fn verification_key(&self) -> VerificationKey {
+        self.verification_key.clone()
+    }
+
+    pub fn to_bytes(&self) -> Vec<u8> {
+        // Schema is coconutkeypair[14]|secret_key_len[8]|secret_key[secret_key_len]|verification_key_len[8]|verification_key[verification_key_len]|signer_index[8] - optional
+        self.to_byte_vec()
+    }
+
+    pub fn from_bytes(bytes: &[u8]) -> Result<Self> {
+        KeyPair::try_from_byte_slice(bytes)
+    }
+}
+
+impl Bytable for KeyPair {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        // Schema is coconutkeypair[14]|secret_key_len[8]|secret_key[secret_key_len]|verification_key_len[8]|verification_key[verification_key_len]|signer_index[8] - optional
+        let mut byts = vec![];
+        let secret_key_bytes = self.secret_key.to_bytes();
+        let secret_key_len = (secret_key_bytes.len() as u64).to_le_bytes();
+        let verification_key_bytes = self.verification_key.to_bytes();
+        let verification_key_len = (verification_key_bytes.len() as u64).to_le_bytes();
+        byts.extend_from_slice(Self::MARKER_BYTES);
+        byts.extend_from_slice(&secret_key_len);
+        byts.extend_from_slice(&secret_key_bytes);
+        byts.extend_from_slice(&verification_key_len);
+        byts.extend_from_slice(&verification_key_bytes);
+        if let Some(index) = self.index {
+            byts.extend_from_slice(&index.to_le_bytes())
+        }
+        byts
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self> {
+        KeyPair::try_from(slice)
+    }
+}
+
+impl Base58 for KeyPair {}
+
+impl TryFrom<&[u8]> for KeyPair {
+    type Error = CoconutError;
+
+    fn try_from(bytes: &[u8]) -> Result<KeyPair> {
+        let header_len = Self::MARKER_BYTES.len();
+
+        // we must be able to at the very least read the length of secret key which is past the header
+        // and is 8 bytes long
+        if bytes.len() < header_len + 8 {
+            return Err(CoconutError::DeserializationMinLength {
+                min: header_len + 8,
+                actual: bytes.len(),
+            });
+        }
+
+        let secret_key_len =
+            u64::from_le_bytes(bytes[header_len..header_len + 8].try_into().unwrap()) as usize;
+        let secret_key_start = header_len + 8;
+
+        let secret_key =
+            SecretKey::try_from(&bytes[secret_key_start..secret_key_start + secret_key_len])?;
+
+        // we must be able to read the length of verification key
+        if bytes.len() < secret_key_start + secret_key_len + 8 {
+            return Err(CoconutError::DeserializationMinLength {
+                min: secret_key_start + secret_key_len + 8,
+                actual: bytes.len(),
+            });
+        }
+
+        let verification_key_len = u64::from_le_bytes(
+            bytes[secret_key_start + secret_key_len..secret_key_start + secret_key_len + 8]
+                .try_into()
+                .unwrap(),
+        ) as usize;
+        let verification_key_start = secret_key_start + secret_key_len + 8;
+
+        let verification_key = VerificationKey::try_from(
+            &bytes[verification_key_start..verification_key_start + verification_key_len],
+        )?;
+        let consumed_bytes = verification_key_start + verification_key_len;
+        let index = if consumed_bytes < bytes.len() && [consumed_bytes..].len() == 8 {
+            Some(u64::from_le_bytes(
+                bytes[consumed_bytes..consumed_bytes + 8]
+                    .try_into()
+                    .unwrap(),
+            ))
+        } else {
+            None
+        };
+        Ok(KeyPair {
+            secret_key,
+            verification_key,
+            index,
+        })
+    }
+}
+
+/// Generate a single Coconut keypair ((x, y0, y1...), (g2^x, g2^y0, ...)).
+/// It is not suitable for threshold credentials as all subsequent calls to `keygen` generate keys
+/// that are independent of each other.
+#[cfg(test)]
+pub fn keygen(params: &Parameters) -> KeyPair {
+    let attributes = params.gen_hs().len();
+
+    let x = params.random_scalar();
+    let ys = params.n_random_scalars(attributes);
+
+    let secret_key = SecretKey { x, ys };
+    let verification_key = secret_key.verification_key(params);
+
+    KeyPair {
+        secret_key,
+        verification_key,
+        index: None,
+    }
+}
+
+/// Generate a set of n Coconut keypairs [((x, y0, y1...), (g2^x, g2^y0, ...)), ...],
+/// such that they support threshold aggregation by `threshold` number of parties.
+/// It is expected that this procedure is executed by a Trusted Third Party.
+pub fn ttp_keygen(
+    params: &Parameters,
+    threshold: u64,
+    num_authorities: u64,
+) -> Result<Vec<KeyPair>> {
+    if threshold == 0 {
+        return Err(CoconutError::Setup(
+            "Tried to generate threshold keys with a 0 threshold value".to_string(),
+        ));
+    }
+
+    if threshold > num_authorities {
+        return Err(
+            CoconutError::Setup(
+                "Tried to generate threshold keys for threshold value being higher than number of the signing authorities".to_string(),
+            ));
+    }
+
+    let attributes = params.gen_hs().len();
+
+    // generate polynomials
+    let v = Polynomial::new_random(params, threshold - 1);
+    let ws = (0..attributes)
+        .map(|_| Polynomial::new_random(params, threshold - 1))
+        .collect::<Vec<_>>();
+
+    // TODO: potentially if we had some known authority identifier we could use that instead
+    // of the increasing (1,2,3,...) sequence
+    let polynomial_indices = (1..=num_authorities).collect::<Vec<_>>();
+
+    // generate polynomial shares
+    let x = polynomial_indices
+        .iter()
+        .map(|&id| v.evaluate(&Scalar::from(id)));
+    let ys = polynomial_indices.iter().map(|&id| {
+        ws.iter()
+            .map(|w| w.evaluate(&Scalar::from(id)))
+            .collect::<Vec<_>>()
+    });
+
+    // finally set the keys
+    let secret_keys = x.zip(ys).map(|(x, ys)| SecretKey { x, ys });
+
+    let keypairs = secret_keys
+        .zip(polynomial_indices.iter())
+        .map(|(secret_key, index)| {
+            let verification_key = secret_key.verification_key(params);
+            KeyPair {
+                secret_key,
+                verification_key,
+                index: Some(*index),
+            }
+        })
+        .collect();
+
+    Ok(keypairs)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::scheme::setup::setup;
+
+    use super::*;
+
+    #[test]
+    fn keypair_bytes_roundtrip() {
+        let mut params1 = setup(1).unwrap();
+        let mut params5 = setup(5).unwrap();
+
+        let keypair1 = keygen(&mut params1);
+        let keypair5 = keygen(&mut params5);
+
+        let bytes1 = keypair1.to_bytes();
+        let bytes5 = keypair5.to_bytes();
+
+        assert_eq!(KeyPair::from_bytes(&bytes1).unwrap(), keypair1);
+        assert_eq!(KeyPair::from_bytes(&bytes5).unwrap(), keypair5);
+    }
+
+    #[test]
+    fn secret_key_bytes_roundtrip() {
+        let mut params1 = setup(1).unwrap();
+        let mut params5 = setup(5).unwrap();
+
+        let keypair1 = keygen(&mut params1);
+        let keypair5 = keygen(&mut params5);
+
+        let bytes1 = keypair1.secret_key.to_bytes();
+        let bytes5 = keypair5.secret_key.to_bytes();
+
+        assert_eq!(SecretKey::from_bytes(&bytes1).unwrap(), keypair1.secret_key);
+        assert_eq!(SecretKey::from_bytes(&bytes5).unwrap(), keypair5.secret_key);
+    }
+
+    #[test]
+    fn verification_key_bytes_roundtrip() {
+        let mut params1 = setup(1).unwrap();
+        let mut params5 = setup(5).unwrap();
+
+        let keypair1 = &keygen(&mut params1);
+        let keypair5 = &keygen(&mut params5);
+
+        let bytes1: Vec<u8> = keypair1.verification_key.to_bytes();
+        let bytes5: Vec<u8> = keypair5.verification_key.to_bytes();
+
+        assert_eq!(
+            VerificationKey::try_from(bytes1.as_slice()).unwrap(),
+            keypair1.verification_key
+        );
+        assert_eq!(
+            VerificationKey::try_from(bytes5.as_slice()).unwrap(),
+            keypair5.verification_key
+        );
+    }
+}

common/nymcoconut/src/scheme/mod.rs

@@ -0,0 +1,661 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+// TODO: implement https://crates.io/crates/signature traits?
+
+use std::convert::TryFrom;
+use std::convert::TryInto;
+
+use bls12_381::{G1Projective, G2Prepared, G2Projective, Scalar};
+use group::Curve;
+
+pub use keygen::{SecretKey, VerificationKey};
+
+use crate::elgamal::Ciphertext;
+use crate::error::{CoconutError, Result};
+use crate::scheme::setup::Parameters;
+use crate::scheme::verification::check_bilinear_pairing;
+use crate::traits::{Base58, Bytable};
+use crate::utils::try_deserialize_g1_projective;
+use crate::{elgamal, Attribute};
+
+pub mod aggregation;
+pub mod issuance;
+pub mod keygen;
+pub mod setup;
+pub mod verification;
+
+pub type SignerIndex = u64;
+
+// (h, s)
+#[derive(Debug, Clone, Copy)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct Signature(pub(crate) G1Projective, pub(crate) G1Projective);
+
+pub type PartialSignature = Signature;
+
+impl TryFrom<&[u8]> for Signature {
+    type Error = CoconutError;
+
+    fn try_from(bytes: &[u8]) -> Result<Signature> {
+        if bytes.len() != 96 {
+            return Err(CoconutError::Deserialization(format!(
+                "Signature must be exactly 96 bytes, got {}",
+                bytes.len()
+            )));
+        }
+
+        let sig1_bytes: &[u8; 48] = &bytes[..48].try_into().expect("Slice size != 48");
+        let sig2_bytes: &[u8; 48] = &bytes[48..].try_into().expect("Slice size != 48");
+
+        let sig1 = try_deserialize_g1_projective(
+            sig1_bytes,
+            CoconutError::Deserialization("Failed to deserialize compressed sig1".to_string()),
+        )?;
+
+        let sig2 = try_deserialize_g1_projective(
+            sig2_bytes,
+            CoconutError::Deserialization("Failed to deserialize compressed sig2".to_string()),
+        )?;
+
+        Ok(Signature(sig1, sig2))
+    }
+}
+
+impl Signature {
+    pub(crate) fn sig1(&self) -> &G1Projective {
+        &self.0
+    }
+
+    pub(crate) fn sig2(&self) -> &G1Projective {
+        &self.1
+    }
+
+    pub fn randomise(&self, params: &Parameters) -> (Signature, Scalar) {
+        let r = params.random_scalar();
+        let r_prime = params.random_scalar();
+        let h_prime = self.0 * r_prime;
+        let s_prime = (self.1 * r_prime) + (h_prime * r);
+        (Signature(h_prime, s_prime), r)
+    }
+
+    pub fn to_bytes(self) -> [u8; 96] {
+        let mut bytes = [0u8; 96];
+        bytes[..48].copy_from_slice(&self.0.to_affine().to_compressed());
+        bytes[48..].copy_from_slice(&self.1.to_affine().to_compressed());
+        bytes
+    }
+
+    pub fn from_bytes(bytes: &[u8]) -> Result<Signature> {
+        Signature::try_from(bytes)
+    }
+}
+
+impl Bytable for Signature {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        self.to_bytes().to_vec()
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self> {
+        Signature::from_bytes(slice)
+    }
+}
+
+impl Base58 for Signature {}
+
+#[derive(Debug)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct BlindedSignature(G1Projective, elgamal::Ciphertext);
+
+impl Bytable for BlindedSignature {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        self.to_bytes().to_vec()
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self> {
+        Self::from_bytes(slice)
+    }
+}
+
+impl Base58 for BlindedSignature {}
+
+impl TryFrom<&[u8]> for BlindedSignature {
+    type Error = CoconutError;
+
+    fn try_from(bytes: &[u8]) -> Result<BlindedSignature> {
+        if bytes.len() != 144 {
+            return Err(CoconutError::Deserialization(format!(
+                "BlindedSignature must be exactly 144 bytes, got {}",
+                bytes.len()
+            )));
+        }
+
+        let h_bytes: &[u8; 48] = &bytes[..48].try_into().expect("Slice size != 48");
+
+        let h = try_deserialize_g1_projective(
+            h_bytes,
+            CoconutError::Deserialization("Failed to deserialize compressed h".to_string()),
+        )?;
+        let c_tilde = Ciphertext::try_from(&bytes[48..])?;
+
+        Ok(BlindedSignature(h, c_tilde))
+    }
+}
+
+impl BlindedSignature {
+    pub fn unblind(
+        &self,
+        params: &Parameters,
+        private_key: &elgamal::PrivateKey,
+        partial_verification_key: &VerificationKey,
+        private_attributes: &[Attribute],
+        public_attributes: &[Attribute],
+        commitment_hash: &G1Projective,
+    ) -> Result<Signature> {
+        // parse the signature
+        let h = &self.0;
+        let c = &self.1;
+        let sig2 = private_key.decrypt(c);
+
+        // Verify the commitment hash
+        if !(commitment_hash == h) {
+            return Err(CoconutError::Unblind(
+                "Verification of commitment hash from signature failed".to_string(),
+            ));
+        }
+
+        let alpha = partial_verification_key.alpha;
+
+        let tmp = private_attributes
+            .iter()
+            .chain(public_attributes.iter())
+            .zip(partial_verification_key.beta.iter())
+            .map(|(attr, beta_i)| beta_i * attr)
+            .sum::<G2Projective>();
+
+        // Verify the signature share
+        if !check_bilinear_pairing(
+            &h.to_affine(),
+            &G2Prepared::from((alpha + tmp).to_affine()),
+            &sig2.to_affine(),
+            params.prepared_miller_g2(),
+        ) {
+            return Err(CoconutError::Unblind(
+                "Verification of signature share failed".to_string(),
+            ));
+        }
+
+        Ok(Signature(self.0, sig2))
+    }
+
+    pub fn to_bytes(&self) -> [u8; 144] {
+        let mut bytes = [0u8; 144];
+        bytes[..48].copy_from_slice(&self.0.to_affine().to_compressed());
+        bytes[48..].copy_from_slice(&self.1.to_bytes());
+        bytes
+    }
+
+    pub fn from_bytes(bytes: &[u8]) -> Result<BlindedSignature> {
+        BlindedSignature::try_from(bytes)
+    }
+}
+
+// perhaps this should take signature by reference? we'll see how it goes
+pub struct SignatureShare {
+    signature: Signature,
+    index: SignerIndex,
+}
+
+impl SignatureShare {
+    pub fn new(signature: Signature, index: SignerIndex) -> Self {
+        SignatureShare { signature, index }
+    }
+
+    pub fn signature(&self) -> &Signature {
+        &self.signature
+    }
+
+    pub fn index(&self) -> SignerIndex {
+        self.index
+    }
+
+    // pub fn aggregate(shares: &[Self]) -> Result<Signature> {
+    //     aggregate_signature_shares(shares)
+    // }
+}
+
+#[cfg(test)]
+mod tests {
+    use group::GroupEncoding;
+
+    use crate::hash_to_scalar;
+    use crate::scheme::aggregation::{aggregate_signatures, aggregate_verification_keys};
+    use crate::scheme::issuance::{blind_sign, prepare_blind_sign, sign};
+    use crate::scheme::keygen::{keygen, ttp_keygen};
+    use crate::scheme::verification::{prove_bandwidth_credential, verify, verify_credential};
+    use crate::utils::hash_g1;
+
+    use super::*;
+
+    #[test]
+    fn unblind_returns_error_if_integrity_check_on_commitment_hash_fails() {
+        let mut params = Parameters::new(2).unwrap();
+        let private_attributes = params.n_random_scalars(2 as usize);
+        let elgamal_keypair = elgamal::elgamal_keygen(&mut params);
+
+        let lambda =
+            prepare_blind_sign(&mut params, &elgamal_keypair, &private_attributes, &[]).unwrap();
+
+        let keypair1 = keygen(&mut params);
+
+        let sig1 = blind_sign(
+            &mut params,
+            &keypair1.secret_key(),
+            elgamal_keypair.public_key(),
+            &lambda,
+            &[],
+        )
+        .unwrap();
+
+        let wrong_commitment_opening = params.random_scalar();
+        let wrong_commitment = params.gen1() * wrong_commitment_opening;
+        let fake_commitment_hash = hash_g1(wrong_commitment.to_bytes());
+        assert!(sig1
+            .unblind(
+                &params,
+                elgamal_keypair.private_key(),
+                &keypair1.verification_key(),
+                &private_attributes,
+                &[],
+                &fake_commitment_hash,
+            )
+            .is_err());
+    }
+
+    #[test]
+    fn unblind_returns_error_if_signature_verification_fails() {
+        let mut params = Parameters::new(2).unwrap();
+        let private_attributes = vec![hash_to_scalar("Attribute1"), hash_to_scalar("Attribute2")];
+        let private_attributes2 = vec![hash_to_scalar("Attribute3"), hash_to_scalar("Attribute4")];
+        let elgamal_keypair = elgamal::elgamal_keygen(&mut params);
+
+        let lambda =
+            prepare_blind_sign(&mut params, &elgamal_keypair, &private_attributes, &[]).unwrap();
+
+        let keypair1 = keygen(&mut params);
+
+        let sig1 = blind_sign(
+            &mut params,
+            &keypair1.secret_key(),
+            elgamal_keypair.public_key(),
+            &lambda,
+            &[],
+        )
+        .unwrap();
+
+        assert!(sig1
+            .unblind(
+                &params,
+                elgamal_keypair.private_key(),
+                &keypair1.verification_key(),
+                &private_attributes2,
+                &[],
+                &lambda.get_commitment_hash(),
+            )
+            .is_err());
+    }
+
+    #[test]
+    fn verification_on_two_private_attributes() {
+        let mut params = Parameters::new(2).unwrap();
+        let serial_number = params.random_scalar();
+        let binding_number = params.random_scalar();
+        let private_attributes = vec![serial_number, binding_number];
+        let elgamal_keypair = elgamal::elgamal_keygen(&mut params);
+
+        let keypair1 = keygen(&mut params);
+        let keypair2 = keygen(&mut params);
+
+        let lambda =
+            prepare_blind_sign(&mut params, &elgamal_keypair, &private_attributes, &[]).unwrap();
+
+        let sig1 = blind_sign(
+            &mut params,
+            &keypair1.secret_key(),
+            elgamal_keypair.public_key(),
+            &lambda,
+            &[],
+        )
+        .unwrap()
+        .unblind(
+            &params,
+            elgamal_keypair.private_key(),
+            &keypair1.verification_key(),
+            &private_attributes,
+            &[],
+            &lambda.get_commitment_hash(),
+        )
+        .unwrap();
+
+        let sig2 = blind_sign(
+            &mut params,
+            &keypair2.secret_key(),
+            elgamal_keypair.public_key(),
+            &lambda,
+            &[],
+        )
+        .unwrap()
+        .unblind(
+            &params,
+            elgamal_keypair.private_key(),
+            &keypair2.verification_key(),
+            &private_attributes,
+            &[],
+            &lambda.get_commitment_hash(),
+        )
+        .unwrap();
+
+        let theta1 = prove_bandwidth_credential(
+            &mut params,
+            &keypair1.verification_key(),
+            &sig1,
+            serial_number,
+            binding_number,
+        )
+        .unwrap();
+
+        let theta2 = prove_bandwidth_credential(
+            &mut params,
+            &keypair2.verification_key(),
+            &sig2,
+            serial_number,
+            binding_number,
+        )
+        .unwrap();
+
+        assert!(verify_credential(
+            &params,
+            &keypair1.verification_key(),
+            &theta1,
+            &[],
+        ));
+
+        assert!(verify_credential(
+            &params,
+            &keypair2.verification_key(),
+            &theta2,
+            &[],
+        ));
+
+        assert!(!verify_credential(
+            &params,
+            &keypair1.verification_key(),
+            &theta2,
+            &[],
+        ));
+    }
+
+    #[test]
+    fn verification_on_two_public_attributes() {
+        let mut params = Parameters::new(2).unwrap();
+        let attributes = params.n_random_scalars(2);
+
+        let keypair1 = keygen(&mut params);
+        let keypair2 = keygen(&mut params);
+        let sig1 = sign(&mut params, &keypair1.secret_key(), &attributes).unwrap();
+        let sig2 = sign(&mut params, &keypair2.secret_key(), &attributes).unwrap();
+
+        assert!(verify(
+            &params,
+            &keypair1.verification_key(),
+            &attributes,
+            &sig1,
+        ));
+
+        assert!(!verify(
+            &params,
+            &keypair2.verification_key(),
+            &attributes,
+            &sig1,
+        ));
+
+        assert!(!verify(
+            &params,
+            &keypair1.verification_key(),
+            &attributes,
+            &sig2,
+        ));
+    }
+
+    #[test]
+    fn verification_on_two_public_and_two_private_attributes() {
+        let mut params = Parameters::new(4).unwrap();
+        let public_attributes = params.n_random_scalars(2);
+        let serial_number = params.random_scalar();
+        let binding_number = params.random_scalar();
+        let private_attributes = vec![serial_number, binding_number];
+        let elgamal_keypair = elgamal::elgamal_keygen(&mut params);
+
+        let keypair1 = keygen(&mut params);
+        let keypair2 = keygen(&mut params);
+
+        let lambda = prepare_blind_sign(
+            &mut params,
+            &elgamal_keypair,
+            &private_attributes,
+            &public_attributes,
+        )
+        .unwrap();
+
+        let sig1 = blind_sign(
+            &mut params,
+            &keypair1.secret_key(),
+            elgamal_keypair.public_key(),
+            &lambda,
+            &public_attributes,
+        )
+        .unwrap()
+        .unblind(
+            &params,
+            elgamal_keypair.private_key(),
+            &keypair1.verification_key(),
+            &private_attributes,
+            &public_attributes,
+            &lambda.get_commitment_hash(),
+        )
+        .unwrap();
+
+        let sig2 = blind_sign(
+            &mut params,
+            &keypair2.secret_key(),
+            elgamal_keypair.public_key(),
+            &lambda,
+            &public_attributes,
+        )
+        .unwrap()
+        .unblind(
+            &params,
+            elgamal_keypair.private_key(),
+            &keypair2.verification_key(),
+            &private_attributes,
+            &public_attributes,
+            &lambda.get_commitment_hash(),
+        )
+        .unwrap();
+
+        let theta1 = prove_bandwidth_credential(
+            &mut params,
+            &keypair1.verification_key(),
+            &sig1,
+            serial_number,
+            binding_number,
+        )
+        .unwrap();
+
+        let theta2 = prove_bandwidth_credential(
+            &mut params,
+            &keypair2.verification_key(),
+            &sig2,
+            serial_number,
+            binding_number,
+        )
+        .unwrap();
+
+        assert!(verify_credential(
+            &params,
+            &keypair1.verification_key(),
+            &theta1,
+            &public_attributes,
+        ));
+
+        assert!(verify_credential(
+            &params,
+            &keypair2.verification_key(),
+            &theta2,
+            &public_attributes,
+        ));
+
+        assert!(!verify_credential(
+            &params,
+            &keypair1.verification_key(),
+            &theta2,
+            &public_attributes,
+        ));
+    }
+
+    #[test]
+    fn verification_on_two_public_and_two_private_attributes_from_two_signers() {
+        let mut params = Parameters::new(4).unwrap();
+        let public_attributes = params.n_random_scalars(2);
+        let serial_number = params.random_scalar();
+        let binding_number = params.random_scalar();
+        let private_attributes = vec![serial_number, binding_number];
+        let elgamal_keypair = elgamal::elgamal_keygen(&params);
+
+        let keypairs = ttp_keygen(&mut params, 2, 3).unwrap();
+
+        let lambda = prepare_blind_sign(
+            &mut params,
+            &elgamal_keypair,
+            &private_attributes,
+            &public_attributes,
+        )
+        .unwrap();
+
+        let sigs = keypairs
+            .iter()
+            .map(|keypair| {
+                blind_sign(
+                    &mut params,
+                    &keypair.secret_key(),
+                    elgamal_keypair.public_key(),
+                    &lambda,
+                    &public_attributes,
+                )
+                .unwrap()
+                .unblind(
+                    &params,
+                    elgamal_keypair.private_key(),
+                    &keypair.verification_key(),
+                    &private_attributes,
+                    &public_attributes,
+                    &lambda.get_commitment_hash(),
+                )
+                .unwrap()
+            })
+            .collect::<Vec<_>>();
+
+        let vks = keypairs
+            .into_iter()
+            .map(|keypair| keypair.verification_key())
+            .collect::<Vec<_>>();
+
+        let mut attributes = Vec::with_capacity(private_attributes.len() + public_attributes.len());
+        attributes.extend_from_slice(&private_attributes);
+        attributes.extend_from_slice(&public_attributes);
+
+        let aggr_vk = aggregate_verification_keys(&vks[..2], Some(&[1, 2])).unwrap();
+        let aggr_sig =
+            aggregate_signatures(&params, &aggr_vk, &attributes, &sigs[..2], Some(&[1, 2]))
+                .unwrap();
+
+        let theta = prove_bandwidth_credential(
+            &mut params,
+            &aggr_vk,
+            &aggr_sig,
+            serial_number,
+            binding_number,
+        )
+        .unwrap();
+
+        assert!(verify_credential(
+            &params,
+            &aggr_vk,
+            &theta,
+            &public_attributes,
+        ));
+
+        // taking different subset of keys and credentials
+        let aggr_vk = aggregate_verification_keys(&vks[1..], Some(&[2, 3])).unwrap();
+        let aggr_sig =
+            aggregate_signatures(&params, &aggr_vk, &attributes, &sigs[1..], Some(&[2, 3]))
+                .unwrap();
+
+        let theta = prove_bandwidth_credential(
+            &mut params,
+            &aggr_vk,
+            &aggr_sig,
+            serial_number,
+            binding_number,
+        )
+        .unwrap();
+
+        assert!(verify_credential(
+            &params,
+            &aggr_vk,
+            &theta,
+            &public_attributes,
+        ));
+    }
+
+    #[test]
+    fn signature_bytes_roundtrip() {
+        let params = Parameters::default();
+        let r = params.random_scalar();
+        let s = params.random_scalar();
+        let signature = Signature(params.gen1() * r, params.gen1() * s);
+        let bytes = signature.to_bytes();
+
+        // also make sure it is equivalent to the internal g1 compressed bytes concatenated
+        let expected_bytes = [
+            signature.0.to_affine().to_compressed(),
+            signature.1.to_affine().to_compressed(),
+        ]
+        .concat();
+        assert_eq!(expected_bytes, bytes);
+        assert_eq!(signature, Signature::try_from(&bytes[..]).unwrap())
+    }
+
+    #[test]
+    fn blinded_signature_bytes_roundtrip() {
+        let params = Parameters::default();
+        let r = params.random_scalar();
+        let s = params.random_scalar();
+        let t = params.random_scalar();
+        let blinded_sig = BlindedSignature(
+            params.gen1() * t,
+            Ciphertext(params.gen1() * r, params.gen1() * s),
+        );
+        let bytes = blinded_sig.to_bytes();
+
+        // also make sure it is equivalent to the internal g1 compressed bytes concatenated
+        let expected_bytes = [
+            blinded_sig.0.to_affine().to_compressed(),
+            blinded_sig.1 .0.to_affine().to_compressed(),
+            blinded_sig.1 .1.to_affine().to_compressed(),
+        ]
+        .concat();
+        assert_eq!(expected_bytes, bytes);
+        assert_eq!(blinded_sig, BlindedSignature::try_from(&bytes[..]).unwrap())
+    }
+}

common/nymcoconut/src/scheme/setup.rs

@@ -0,0 +1,90 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use bls12_381::{G1Affine, G2Affine, G2Prepared, Scalar};
+use ff::Field;
+use group::Curve;
+use rand::thread_rng;
+
+use crate::error::{CoconutError, Result};
+use crate::utils::hash_g1;
+
+/// System-wide parameters used for the protocol
+pub struct Parameters {
+    /// Generator of the G1 group
+    g1: G1Affine,
+
+    /// Additional generators of the G1 group
+    hs: Vec<G1Affine>,
+
+    /// Generator of the G2 group
+    g2: G2Affine,
+
+    /// Precomputed G2 generator used for the miller loop
+    _g2_prepared_miller: G2Prepared,
+}
+
+impl Parameters {
+    pub fn new(num_attributes: u32) -> Result<Parameters> {
+        if num_attributes == 0 {
+            return Err(CoconutError::Setup(
+                "Tried to setup the scheme for 0 attributes".to_string(),
+            ));
+        }
+
+        let hs = (1..=num_attributes)
+            .map(|i| hash_g1(format!("h{}", i)).to_affine())
+            .collect();
+
+        Ok(Parameters {
+            g1: G1Affine::generator(),
+            hs,
+            g2: G2Affine::generator(),
+            _g2_prepared_miller: G2Prepared::from(G2Affine::generator()),
+        })
+    }
+
+    pub(crate) fn gen1(&self) -> &G1Affine {
+        &self.g1
+    }
+
+    pub(crate) fn gen2(&self) -> &G2Affine {
+        &self.g2
+    }
+
+    pub(crate) fn prepared_miller_g2(&self) -> &G2Prepared {
+        &self._g2_prepared_miller
+    }
+
+    pub(crate) fn gen_hs(&self) -> &[G1Affine] {
+        &self.hs
+    }
+
+    pub fn random_scalar(&self) -> Scalar {
+        // lazily-initialized thread-local random number generator, seeded by the system
+        let mut rng = thread_rng();
+        Scalar::random(&mut rng)
+    }
+
+    pub fn n_random_scalars(&self, n: usize) -> Vec<Scalar> {
+        (0..n).map(|_| self.random_scalar()).collect()
+    }
+}
+
+pub fn setup(num_attributes: u32) -> Result<Parameters> {
+    Parameters::new(num_attributes)
+}
+
+// for ease of use in tests requiring params
+// TODO: not sure if this will have to go away when tests require some specific number of generators
+#[cfg(test)]
+impl Default for Parameters {
+    fn default() -> Self {
+        Parameters {
+            g1: G1Affine::generator(),
+            hs: Vec::new(),
+            g2: G2Affine::generator(),
+            _g2_prepared_miller: G2Prepared::from(G2Affine::generator()),
+        }
+    }
+}

common/nymcoconut/src/scheme/verification.rs

@@ -0,0 +1,296 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use core::ops::Neg;
+use std::convert::TryFrom;
+use std::convert::TryInto;
+
+use bls12_381::{multi_miller_loop, G1Affine, G2Prepared, G2Projective, Scalar};
+use group::{Curve, Group};
+
+use crate::error::{CoconutError, Result};
+use crate::proofs::ProofKappaZeta;
+use crate::scheme::setup::Parameters;
+use crate::scheme::Signature;
+use crate::scheme::VerificationKey;
+use crate::traits::{Base58, Bytable};
+use crate::utils::try_deserialize_g2_projective;
+use crate::Attribute;
+
+// TODO NAMING: this whole thing
+// Theta
+#[derive(Debug)]
+#[cfg_attr(test, derive(PartialEq))]
+pub struct Theta {
+    // blinded_message (kappa)
+    pub blinded_message: G2Projective,
+    // blinded serial number (zeta)
+    pub blinded_serial_number: G2Projective,
+    // sigma
+    pub credential: Signature,
+    // pi_v
+    pub pi_v: ProofKappaZeta,
+}
+
+impl TryFrom<&[u8]> for Theta {
+    type Error = CoconutError;
+
+    fn try_from(bytes: &[u8]) -> Result<Theta> {
+        if bytes.len() < 288 {
+            return Err(
+                CoconutError::Deserialization(
+                    format!("Tried to deserialize theta with insufficient number of bytes, expected >= 288, got {}", bytes.len()),
+                ));
+        }
+
+        let blinded_message_bytes = bytes[..96].try_into().unwrap();
+        let blinded_message = try_deserialize_g2_projective(
+            &blinded_message_bytes,
+            CoconutError::Deserialization(
+                "failed to deserialize the blinded message (kappa)".to_string(),
+            ),
+        )?;
+
+        let blinded_serial_number_bytes = bytes[96..192].try_into().unwrap();
+        let blinded_serial_number = try_deserialize_g2_projective(
+            &blinded_serial_number_bytes,
+            CoconutError::Deserialization(
+                "failed to deserialize the blinded serial number (zeta)".to_string(),
+            ),
+        )?;
+        let credential = Signature::try_from(&bytes[192..288])?;
+
+        let pi_v = ProofKappaZeta::from_bytes(&bytes[288..])?;
+
+        Ok(Theta {
+            blinded_message,
+            blinded_serial_number,
+            credential,
+            pi_v,
+        })
+    }
+}
+
+impl Theta {
+    fn verify_proof(&self, params: &Parameters, verification_key: &VerificationKey) -> bool {
+        self.pi_v.verify(
+            params,
+            verification_key,
+            &self.blinded_message,
+            &self.blinded_serial_number,
+        )
+    }
+
+    // blinded message (kappa)  || blinded serial number (zeta) || credential || pi_v
+    pub fn to_bytes(&self) -> Vec<u8> {
+        let blinded_message_bytes = self.blinded_message.to_affine().to_compressed();
+        let blinded_serial_number_bytes = self.blinded_serial_number.to_affine().to_compressed();
+        let credential_bytes = self.credential.to_bytes();
+        let proof_bytes = self.pi_v.to_bytes();
+
+        let mut bytes = Vec::with_capacity(288 + proof_bytes.len());
+        bytes.extend_from_slice(&blinded_message_bytes);
+        bytes.extend_from_slice(&blinded_serial_number_bytes);
+        bytes.extend_from_slice(&credential_bytes);
+        bytes.extend_from_slice(&proof_bytes);
+
+        bytes
+    }
+
+    pub fn from_bytes(bytes: &[u8]) -> Result<Theta> {
+        Theta::try_from(bytes)
+    }
+}
+
+impl Bytable for Theta {
+    fn to_byte_vec(&self) -> Vec<u8> {
+        self.to_bytes()
+    }
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self> {
+        Theta::try_from(slice)
+    }
+}
+
+impl Base58 for Theta {}
+
+pub fn compute_kappa(
+    params: &Parameters,
+    verification_key: &VerificationKey,
+    private_attributes: &[Attribute],
+    blinding_factor: Scalar,
+) -> G2Projective {
+    params.gen2() * blinding_factor
+        + verification_key.alpha
+        + private_attributes
+            .iter()
+            .zip(verification_key.beta.iter())
+            .map(|(priv_attr, beta_i)| beta_i * priv_attr)
+            .sum::<G2Projective>()
+}
+
+pub fn compute_zeta(params: &Parameters, serial_number: Attribute) -> G2Projective {
+    params.gen2() * serial_number
+}
+
+pub fn prove_bandwidth_credential(
+    params: &Parameters,
+    verification_key: &VerificationKey,
+    signature: &Signature,
+    serial_number: Attribute,
+    binding_number: Attribute,
+) -> Result<Theta> {
+    if verification_key.beta.len() < 2 {
+        return Err(
+            CoconutError::Verification(
+                format!("Tried to prove a credential for higher than supported by the provided verification key number of attributes (max: {}, requested: 2)",
+                        verification_key.beta.len()
+                )));
+    }
+
+    // Randomize the signature
+    let (signature_prime, sign_blinding_factor) = signature.randomise(params);
+
+    // blinded_message : kappa in the paper.
+    // Value kappa is needed since we want to show a signature sigma'.
+    // In order to verify sigma' we need both the verification key vk and the message m.
+    // However, we do not want to reveal m to whomever we are showing the signature.
+    // Thus, we need kappa which allows us to verify sigma'. In particular,
+    // kappa is computed on m as input, but thanks to the use or random value r,
+    // it does not reveal any information about m.
+    let private_attributes = vec![serial_number, binding_number];
+    let blinded_message = compute_kappa(
+        params,
+        verification_key,
+        &private_attributes,
+        sign_blinding_factor,
+    );
+
+    // zeta is a commitment to the serial number (i.e., a public value associated with the serial number)
+    let blinded_serial_number = compute_zeta(params, serial_number);
+
+    let pi_v = ProofKappaZeta::construct(
+        params,
+        verification_key,
+        &serial_number,
+        &binding_number,
+        &sign_blinding_factor,
+        &blinded_message,
+        &blinded_serial_number,
+    );
+
+    Ok(Theta {
+        blinded_message,
+        blinded_serial_number,
+        credential: signature_prime,
+        pi_v,
+    })
+}
+
+/// Checks whether e(P, Q) * e(-R, S) == id
+pub fn check_bilinear_pairing(p: &G1Affine, q: &G2Prepared, r: &G1Affine, s: &G2Prepared) -> bool {
+    // checking e(P, Q) * e(-R, S) == id
+    // is equivalent to checking e(P, Q) == e(R, S)
+    // but requires only a single final exponentiation rather than two of them
+    // and therefore, as seen via benchmarks.rs, is almost 50% faster
+    // (1.47ms vs 2.45ms, tested on R9 5900X)
+
+    let multi_miller = multi_miller_loop(&[(p, q), (&r.neg(), s)]);
+    multi_miller.final_exponentiation().is_identity().into()
+}
+
+pub fn verify_credential(
+    params: &Parameters,
+    verification_key: &VerificationKey,
+    theta: &Theta,
+    public_attributes: &[Attribute],
+) -> bool {
+    if public_attributes.len() + theta.pi_v.private_attributes_len() > verification_key.beta.len() {
+        return false;
+    }
+
+    if !theta.verify_proof(params, verification_key) {
+        return false;
+    }
+
+    let kappa = if public_attributes.is_empty() {
+        theta.blinded_message
+    } else {
+        let signed_public_attributes = public_attributes
+            .iter()
+            .zip(
+                verification_key
+                    .beta
+                    .iter()
+                    .skip(theta.pi_v.private_attributes_len()),
+            )
+            .map(|(pub_attr, beta_i)| beta_i * pub_attr)
+            .sum::<G2Projective>();
+
+        theta.blinded_message + signed_public_attributes
+    };
+
+    check_bilinear_pairing(
+        &theta.credential.0.to_affine(),
+        &G2Prepared::from(kappa.to_affine()),
+        &(theta.credential.1).to_affine(),
+        params.prepared_miller_g2(),
+    ) && !bool::from(theta.credential.0.is_identity())
+}
+
+// Used in tests only
+#[cfg(test)]
+pub fn verify(
+    params: &Parameters,
+    verification_key: &VerificationKey,
+    public_attributes: &[Attribute],
+    sig: &Signature,
+) -> bool {
+    let kappa = (verification_key.alpha
+        + public_attributes
+            .iter()
+            .zip(verification_key.beta.iter())
+            .map(|(m_i, b_i)| b_i * m_i)
+            .sum::<G2Projective>())
+    .to_affine();
+
+    check_bilinear_pairing(
+        &sig.0.to_affine(),
+        &G2Prepared::from(kappa),
+        &sig.1.to_affine(),
+        params.prepared_miller_g2(),
+    ) && !bool::from(sig.0.is_identity())
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::scheme::keygen::keygen;
+    use crate::scheme::setup::setup;
+
+    use super::*;
+
+    #[test]
+    fn theta_bytes_roundtrip() {
+        let mut params = setup(2).unwrap();
+
+        let keypair = keygen(&mut params);
+        let r = params.random_scalar();
+        let s = params.random_scalar();
+
+        let signature = Signature(params.gen1() * r, params.gen1() * s);
+        let serial_number = params.random_scalar();
+        let binding_number = params.random_scalar();
+
+        let theta = prove_bandwidth_credential(
+            &mut params,
+            &keypair.verification_key(),
+            &signature,
+            serial_number,
+            binding_number,
+        )
+        .unwrap();
+
+        let bytes = theta.to_bytes();
+        assert_eq!(Theta::try_from(bytes.as_slice()).unwrap(), theta);
+    }
+}

common/nymcoconut/src/tests/e2e.rs

@@ -0,0 +1,106 @@
+use crate::{
+    aggregate_signature_shares, aggregate_verification_keys, blind_sign, elgamal_keygen,
+    prepare_blind_sign, prove_bandwidth_credential, setup, ttp_keygen, verify_credential,
+    CoconutError, Signature, SignatureShare, VerificationKey,
+};
+
+#[test]
+fn main() -> Result<(), CoconutError> {
+    let params = setup(5)?;
+
+    let public_attributes = params.n_random_scalars(2);
+    let serial_number = params.random_scalar();
+    let binding_number = params.random_scalar();
+    let private_attributes = vec![serial_number, binding_number];
+
+    let elgamal_keypair = elgamal_keygen(&params);
+
+    // generate commitment and encryption
+    let blind_sign_request = prepare_blind_sign(
+        &params,
+        &elgamal_keypair,
+        &private_attributes,
+        &public_attributes,
+    )?;
+
+    // generate_keys
+    let coconut_keypairs = ttp_keygen(&params, 2, 3)?;
+
+    let verification_keys: Vec<VerificationKey> = coconut_keypairs
+        .iter()
+        .map(|keypair| keypair.verification_key())
+        .collect();
+
+    // aggregate verification keys
+    let verification_key = aggregate_verification_keys(&verification_keys, Some(&[1, 2, 3]))?;
+
+    // generate blinded signatures
+    let mut blinded_signatures = Vec::new();
+
+    for keypair in coconut_keypairs {
+        let blinded_signature = blind_sign(
+            &params,
+            &keypair.secret_key(),
+            &elgamal_keypair.public_key(),
+            &blind_sign_request,
+            &public_attributes,
+        )?;
+        blinded_signatures.push(blinded_signature)
+    }
+
+    // Unblind
+
+    let unblinded_signatures: Vec<Signature> = blinded_signatures
+        .into_iter()
+        .zip(verification_keys.iter())
+        .map(|(signature, verification_key)| {
+            signature
+                .unblind(
+                    &params,
+                    &elgamal_keypair.private_key(),
+                    &verification_key,
+                    &private_attributes,
+                    &public_attributes,
+                    &blind_sign_request.get_commitment_hash(),
+                )
+                .unwrap()
+        })
+        .collect();
+
+    // Aggregate signatures
+
+    let signature_shares: Vec<SignatureShare> = unblinded_signatures
+        .iter()
+        .enumerate()
+        .map(|(idx, signature)| SignatureShare::new(*signature, (idx + 1) as u64))
+        .collect();
+
+    let mut attributes = Vec::with_capacity(private_attributes.len() + public_attributes.len());
+    attributes.extend_from_slice(&private_attributes);
+    attributes.extend_from_slice(&public_attributes);
+
+    // Randomize credentials and generate any cryptographic material to verify them
+    let signature =
+        aggregate_signature_shares(&params, &verification_key, &attributes, &signature_shares)?;
+
+    // Generate cryptographic material to verify them
+
+    let theta = prove_bandwidth_credential(
+        &params,
+        &verification_key,
+        &signature,
+        serial_number,
+        binding_number,
+    )?;
+
+    // Verify credentials
+
+    assert!(verify_credential(
+        &params,
+        &verification_key,
+        &theta,
+        &public_attributes,
+    ));
+
+    Ok(())
+}

common/nymcoconut/src/tests/mod.rs

@@ -0,0 +1 @@
+mod e2e;

common/nymcoconut/src/traits.rs

@@ -0,0 +1,22 @@
+use crate::CoconutError;
+
+pub trait Bytable
+where
+    Self: Sized,
+{
+    fn to_byte_vec(&self) -> Vec<u8>;
+
+    fn try_from_byte_slice(slice: &[u8]) -> Result<Self, CoconutError>;
+}
+
+pub trait Base58
+where
+    Self: Bytable,
+{
+    fn try_from_bs58<S: AsRef<str>>(x: S) -> Result<Self, CoconutError> {
+        Self::try_from_byte_slice(&bs58::decode(x.as_ref()).into_vec().unwrap())
+    }
+    fn to_bs58(&self) -> String {
+        bs58::encode(self.to_byte_vec()).into_string()
+    }
+}

common/nymcoconut/src/utils.rs

@@ -0,0 +1,386 @@
+// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use core::iter::Sum;
+use core::ops::Mul;
+use std::convert::TryInto;
+
+use bls12_381::hash_to_curve::{ExpandMsgXmd, HashToCurve, HashToField};
+use bls12_381::{G1Affine, G1Projective, G2Affine, G2Projective, Scalar};
+use ff::Field;
+
+use crate::error::{CoconutError, Result};
+use crate::scheme::setup::Parameters;
+use crate::scheme::SignerIndex;
+
+pub struct Polynomial {
+    coefficients: Vec<Scalar>,
+}
+
+impl Polynomial {
+    // for polynomial of degree n, we generate n+1 values
+    // (for example for degree 1, like y = x + 2, we need [2,1])
+    pub fn new_random(params: &Parameters, degree: u64) -> Self {
+        Polynomial {
+            coefficients: params.n_random_scalars((degree + 1) as usize),
+        }
+    }
+
+    /// Evaluates the polynomial at point x.
+    pub fn evaluate(&self, x: &Scalar) -> Scalar {
+        if self.coefficients.is_empty() {
+            Scalar::zero()
+            // if x is zero then we can ignore most of the expensive computation and
+            // just return the last term of the polynomial
+        } else if x.is_zero() {
+            // we checked that coefficients are not empty so unwrap here is fine
+            *self.coefficients.first().unwrap()
+        } else {
+            self.coefficients
+                .iter()
+                .enumerate()
+                // coefficient[n] * x ^ n
+                .map(|(i, coefficient)| coefficient * x.pow(&[i as u64, 0, 0, 0]))
+                .sum()
+        }
+    }
+}
+
+#[inline]
+fn generate_lagrangian_coefficients_at_origin(points: &[u64]) -> Vec<Scalar> {
+    let x = Scalar::zero();
+
+    points
+        .iter()
+        .enumerate()
+        .map(|(i, point_i)| {
+            let mut numerator = Scalar::one();
+            let mut denominator = Scalar::one();
+            let xi = Scalar::from(*point_i);
+
+            for (j, point_j) in points.iter().enumerate() {
+                if j != i {
+                    let xj = Scalar::from(*point_j);
+
+                    // numerator = (x - xs[0]) * ... * (x - xs[j]), j != i
+                    numerator *= x - xj;
+
+                    // denominator = (xs[i] - x[0]) * ... * (xs[i] - x[j]), j != i
+                    denominator *= xi - xj;
+                }
+            }
+            // numerator / denominator
+            numerator * denominator.invert().unwrap()
+        })
+        .collect()
+}
+
+/// Performs a Lagrange interpolation at the origin for a polynomial defined by `points` and `values`.
+/// It can be used for Scalars, G1 and G2 points.
+pub(crate) fn perform_lagrangian_interpolation_at_origin<T>(
+    points: &[SignerIndex],
+    values: &[T],
+) -> Result<T>
+where
+    T: Sum,
+    for<'a> &'a T: Mul<Scalar, Output = T>,
+{
+    if points.is_empty() || values.is_empty() {
+        return Err(CoconutError::Interpolation(
+            "Tried to perform lagrangian interpolation for an empty set of coordinates".to_string(),
+        ));
+    }
+
+    if points.len() != values.len() {
+        return Err(CoconutError::Interpolation(
+            "Tried to perform lagrangian interpolation for an incomplete set of coordinates"
+                .to_string(),
+        ));
+    }
+
+    let coefficients = generate_lagrangian_coefficients_at_origin(points);
+
+    Ok(coefficients
+        .into_iter()
+        .zip(values.iter())
+        .map(|(coeff, val)| val * coeff)
+        .sum())
+}
+
+// A temporary way of hashing particular message into G1.
+// Implementation idea was taken from `threshold_crypto`:
+// https://github.com/poanetwork/threshold_crypto/blob/7709462f2df487ada3bb3243060504b5881f2628/src/lib.rs#L691
+// Eventually it should get replaced by, most likely, the osswu map
+// method once ideally it's implemented inside the pairing crate.
+
+// note: I have absolutely no idea what are the correct domains for those. I just used whatever
+// was given in the test vectors of `Hashing to Elliptic Curves draft-irtf-cfrg-hash-to-curve-11`
+
+// https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-hash-to-curve-11#appendix-J.9.1
+const G1_HASH_DOMAIN: &[u8] = b"QUUX-V01-CS02-with-BLS12381G1_XMD:SHA-256_SSWU_RO_";
+
+// https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-hash-to-curve-11#appendix-K.1
+const SCALAR_HASH_DOMAIN: &[u8] = b"QUUX-V01-CS02-with-expander";
+
+pub(crate) fn hash_g1<M: AsRef<[u8]>>(msg: M) -> G1Projective {
+    <G1Projective as HashToCurve<ExpandMsgXmd<sha2::Sha256>>>::hash_to_curve(msg, G1_HASH_DOMAIN)
+}
+
+pub fn hash_to_scalar<M: AsRef<[u8]>>(msg: M) -> Scalar {
+    let mut output = vec![Scalar::zero()];
+
+    Scalar::hash_to_field::<ExpandMsgXmd<sha2::Sha256>>(
+        msg.as_ref(),
+        SCALAR_HASH_DOMAIN,
+        &mut output,
+    );
+    output[0]
+}
+
+pub(crate) fn try_deserialize_scalar_vec(
+    expected_len: u64,
+    bytes: &[u8],
+    err: CoconutError,
+) -> Result<Vec<Scalar>> {
+    if bytes.len() != expected_len as usize * 32 {
+        return Err(err);
+    }
+
+    let mut out = Vec::with_capacity(expected_len as usize);
+    for i in 0..expected_len as usize {
+        let s_bytes = bytes[i * 32..(i + 1) * 32].try_into().unwrap();
+        let s = match Into::<Option<Scalar>>::into(Scalar::from_bytes(&s_bytes)) {
+            None => return Err(err),
+            Some(scalar) => scalar,
+        };
+        out.push(s)
+    }
+
+    Ok(out)
+}
+
+pub(crate) fn try_deserialize_scalar(bytes: &[u8; 32], err: CoconutError) -> Result<Scalar> {
+    Into::<Option<Scalar>>::into(Scalar::from_bytes(bytes)).ok_or(err)
+}
+
+pub(crate) fn try_deserialize_g1_projective(
+    bytes: &[u8; 48],
+    err: CoconutError,
+) -> Result<G1Projective> {
+    Into::<Option<G1Affine>>::into(G1Affine::from_compressed(bytes))
+        .ok_or(err)
+        .map(G1Projective::from)
+}
+
+pub(crate) fn try_deserialize_g2_projective(
+    bytes: &[u8; 96],
+    err: CoconutError,
+) -> Result<G2Projective> {
+    Into::<Option<G2Affine>>::into(G2Affine::from_compressed(bytes))
+        .ok_or(err)
+        .map(G2Projective::from)
+}
+
+// use core::fmt;
+// #[cfg(feature = "serde")]
+// use serde::de::Visitor;
+// #[cfg(feature = "serde")]
+// use serde::{self, Deserialize, Deserializer, Serialize, Serializer};
+//
+// // #[cfg(feature = "serde")]
+// #[serde(remote = "Scalar")]
+// pub(crate) struct ScalarDef(pub Scalar);
+//
+// // #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+//
+// impl Serialize for ScalarDef {
+//     fn serialize<S>(&self, serializer: S) -> core::result::Result<S::Ok, S::Error>
+//     where
+//         S: Serializer,
+//     {
+//         use serde::ser::SerializeTuple;
+//         let mut tup = serializer.serialize_tuple(32)?;
+//         for byte in self.0.to_bytes().iter() {
+//             tup.serialize_element(byte)?;
+//         }
+//         tup.end()
+//     }
+// }
+//
+// impl<'de> Deserialize<'de> for ScalarDef {
+//     fn deserialize<D>(deserializer: D) -> core::result::Result<Self, D::Error>
+//     where
+//         D: Deserializer<'de>,
+//     {
+//         struct ScalarVisitor;
+//
+//         impl<'de> Visitor<'de> for ScalarVisitor {
+//             type Value = ScalarDef;
+//
+//             fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+//                 formatter.write_str("a 32-byte canonical bls12_381 scalar")
+//             }
+//
+//             fn visit_seq<A>(self, mut seq: A) -> core::result::Result<ScalarDef, A::Error>
+//             where
+//                 A: serde::de::SeqAccess<'de>,
+//             {
+//                 let mut bytes = [0u8; 32];
+//                 for i in 0..32 {
+//                     bytes[i] = seq
+//                         .next_element()?
+//                         .ok_or_else(|| serde::de::Error::invalid_length(i, &"expected 32 bytes"))?;
+//                 }
+//
+//                 let res = Scalar::from_bytes(&bytes);
+//                 if res.is_some().into() {
+//                     Ok(ScalarDef(res.unwrap()))
+//                 } else {
+//                     Err(serde::de::Error::custom(
+//                         &"scalar was not canonically encoded",
+//                     ))
+//                 }
+//             }
+//         }
+//
+//         deserializer.deserialize_tuple(32, ScalarVisitor)
+//     }
+// }
+//
+// #[cfg(feature = "serde")]
+// pub(crate) struct G1ProjectiveSerdeHelper(Scalar);
+//
+// #[cfg(feature = "serde")]
+// pub(crate) struct G2ProjectiveSerdeHelper(Scalar);
+
+#[cfg(test)]
+mod tests {
+    use rand::RngCore;
+
+    use super::*;
+
+    #[test]
+    fn polynomial_evaluation() {
+        // y = 42 (it should be 42 regardless of x)
+        let poly = Polynomial {
+            coefficients: vec![Scalar::from(42)],
+        };
+
+        assert_eq!(Scalar::from(42), poly.evaluate(&Scalar::from(1)));
+        assert_eq!(Scalar::from(42), poly.evaluate(&Scalar::from(0)));
+        assert_eq!(Scalar::from(42), poly.evaluate(&Scalar::from(10)));
+
+        // y = x + 10, at x = 2 (exp: 12)
+        let poly = Polynomial {
+            coefficients: vec![Scalar::from(10), Scalar::from(1)],
+        };
+
+        assert_eq!(Scalar::from(12), poly.evaluate(&Scalar::from(2)));
+
+        // y = x^4 - 5x^2 + 2x - 3, at x = 3 (exp: 39)
+        let poly = Polynomial {
+            coefficients: vec![
+                (-Scalar::from(3)),
+                Scalar::from(2),
+                (-Scalar::from(5)),
+                Scalar::zero(),
+                Scalar::from(1),
+            ],
+        };
+
+        assert_eq!(Scalar::from(39), poly.evaluate(&Scalar::from(3)));
+
+        // empty polynomial
+        let poly = Polynomial {
+            coefficients: vec![],
+        };
+
+        // should always be 0
+        assert_eq!(Scalar::from(0), poly.evaluate(&Scalar::from(1)));
+        assert_eq!(Scalar::from(0), poly.evaluate(&Scalar::from(0)));
+        assert_eq!(Scalar::from(0), poly.evaluate(&Scalar::from(10)));
+    }
+
+    #[test]
+    fn performing_lagrangian_scalar_interpolation_at_origin() {
+        // x^2 + 3
+        // x, f(x):
+        // 1, 4,
+        // 2, 7,
+        // 3, 12,
+        let points = vec![1, 2, 3];
+        let values = vec![Scalar::from(4), Scalar::from(7), Scalar::from(12)];
+
+        assert_eq!(
+            Scalar::from(3),
+            perform_lagrangian_interpolation_at_origin(&points, &values).unwrap()
+        );
+
+        // x^3 + 3x^2 - 5x + 11
+        // x, f(x):
+        // 1, 10
+        // 2, 21
+        // 3, 50
+        // 4, 103
+        let points = vec![1, 2, 3, 4];
+        let values = vec![
+            Scalar::from(10),
+            Scalar::from(21),
+            Scalar::from(50),
+            Scalar::from(103),
+        ];
+
+        assert_eq!(
+            Scalar::from(11),
+            perform_lagrangian_interpolation_at_origin(&points, &values).unwrap()
+        );
+
+        // more points than it is required
+        // x^2 + x + 10
+        // x, f(x)
+        // 1, 12
+        // 2, 16
+        // 3, 22
+        // 4, 30
+        // 5, 40
+        let points = vec![1, 2, 3, 4, 5];
+        let values = vec![
+            Scalar::from(12),
+            Scalar::from(16),
+            Scalar::from(22),
+            Scalar::from(30),
+            Scalar::from(40),
+        ];
+
+        assert_eq!(
+            Scalar::from(10),
+            perform_lagrangian_interpolation_at_origin(&points, &values).unwrap()
+        );
+    }
+
+    #[test]
+    fn hash_g1_sanity_check() {
+        let mut rng = rand::thread_rng();
+        let mut msg1 = [0u8; 1024];
+        rng.fill_bytes(&mut msg1);
+        let mut msg2 = [0u8; 1024];
+        rng.fill_bytes(&mut msg2);
+
+        assert_eq!(hash_g1(msg1), hash_g1(msg1));
+        assert_eq!(hash_g1(msg2), hash_g1(msg2));
+        assert_ne!(hash_g1(msg1), hash_g1(msg2));
+    }
+
+    #[test]
+    fn hash_scalar_sanity_check() {
+        let mut rng = rand::thread_rng();
+        let mut msg1 = [0u8; 1024];
+        rng.fill_bytes(&mut msg1);
+        let mut msg2 = [0u8; 1024];
+        rng.fill_bytes(&mut msg2);
+
+        assert_eq!(hash_to_scalar(msg1), hash_to_scalar(msg1));
+        assert_eq!(hash_to_scalar(msg2), hash_to_scalar(msg2));
+        assert_ne!(hash_to_scalar(msg1), hash_to_scalar(msg2));
+    }
+}

common/nymsphinx/src/receiver.rs

@@ -156,11 +156,9 @@ impl MessageReceiver {
             };
 
             // Finally, remove the zero padding from the message
-            if Self::remove_padding(&mut message).is_err() {
-                return Err(MessageRecoveryError::MalformedReconstructedMessage(
-                    used_sets,
-                ));
-            };
+            Self::remove_padding(&mut message).map_err(|_| {
+                MessageRecoveryError::MalformedReconstructedMessage(used_sets.clone())
+            })?;
 
             Ok(Some((
                 ReconstructedMessage {
@@ -270,7 +268,6 @@ mod message_receiver {
             vec![gateway::Node {
                 owner: "foomp4".to_string(),
                 stake: 123,
-                delegation: 456,
                 location: "unknown".to_string(),
                 host: "1.2.3.4".parse().unwrap(),
                 mix_host: "1.2.3.4:1789".parse().unwrap(),

common/topology/src/gateway.rs

@@ -72,7 +72,6 @@ pub struct Node {
     // somebody correct me if I'm wrong, but we should only ever have a single denom of currency
     // on the network at a type, right?
     pub stake: u128,
-    pub delegation: u128,
     pub location: String,
     pub host: NetworkAddress,
     // we're keeping this as separate resolved field since we do not want to be resolving the potential
@@ -127,7 +126,6 @@ impl<'a> TryFrom<&'a GatewayBond> for Node {
         Ok(Node {
             owner: bond.owner.as_str().to_owned(),
             stake: bond.bond_amount.amount.into(),
-            delegation: bond.total_delegation.amount.into(),
             location: bond.gateway.location.clone(),
             host,
             mix_host,