Jędrzej Stuczyński
74 lines
2.2 KiB
Rust
74 lines
2.2 KiB
Rust
// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
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// SPDX-License-Identifier: Apache-2.0
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use nym_crypto::{
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crypto_hash,
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generic_array::{typenum::Unsigned, GenericArray},
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symmetric::stream_cipher::{generate_key, CipherKey, KeySizeUser},
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OutputSizeUser,
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};
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use nym_sphinx_params::{ReplySurbEncryptionAlgorithm, ReplySurbKeyDigestAlgorithm};
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use rand::{CryptoRng, RngCore};
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use std::fmt::{self, Display, Formatter};
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pub type EncryptionKeyDigest =
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GenericArray<u8, <ReplySurbKeyDigestAlgorithm as OutputSizeUser>::OutputSize>;
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pub type SurbEncryptionKeySize = <ReplySurbEncryptionAlgorithm as KeySizeUser>::KeySize;
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#[derive(Clone, Copy, Debug)]
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pub struct SurbEncryptionKey(CipherKey<ReplySurbEncryptionAlgorithm>);
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#[derive(Debug)]
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pub enum SurbEncryptionKeyError {
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BytesOfInvalidLengthError,
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}
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impl Display for SurbEncryptionKeyError {
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fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
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match self {
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SurbEncryptionKeyError::BytesOfInvalidLengthError => {
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write!(f, "provided bytes have invalid length")
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}
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}
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}
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}
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impl std::error::Error for SurbEncryptionKeyError {}
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impl SurbEncryptionKey {
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/// Generates fresh pseudorandom key that is going to be used by the recipient of the message
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/// to encrypt payload of the reply. It is only generated when reply-SURB is attached.
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pub fn new<R: RngCore + CryptoRng>(rng: &mut R) -> Self {
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SurbEncryptionKey(generate_key::<ReplySurbEncryptionAlgorithm, _>(rng))
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}
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pub fn try_from_bytes(bytes: &[u8]) -> Result<Self, SurbEncryptionKeyError> {
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if bytes.len() != SurbEncryptionKeySize::USIZE {
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return Err(SurbEncryptionKeyError::BytesOfInvalidLengthError);
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}
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Ok(SurbEncryptionKey(GenericArray::clone_from_slice(bytes)))
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}
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pub fn compute_digest(&self) -> EncryptionKeyDigest {
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crypto_hash::compute_digest::<ReplySurbKeyDigestAlgorithm>(&self.0)
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}
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pub fn to_bytes(&self) -> Vec<u8> {
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self.0.to_vec()
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}
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pub fn as_bytes(&self) -> &[u8] {
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self.0.as_ref()
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}
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pub fn size(&self) -> usize {
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self.0.len()
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}
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pub fn inner(&self) -> &CipherKey<ReplySurbEncryptionAlgorithm> {
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&self.0
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}
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}
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