Improve function performance and readability

common/nym_offline_compact_ecash/src/proofs/proof_spend.rs

@@ -744,7 +744,7 @@ mod tests {
         let cc = g1 * o_c + gamma1 * v;
 
         // compute hash of the payment info
-        let pay_info = PayInfo { info: [37u8; 32] };
+        let pay_info = PayInfo { info: [37u8; 88] };
         let rr = hash_to_scalar(pay_info.info);
 
         // evaluate the pseudorandom functions

common/nym_offline_compact_ecash/src/scheme/identify.rs

@@ -107,7 +107,7 @@ mod tests {
         .unwrap();
 
         // Let's try to spend some coins
-        let pay_info1 = PayInfo { info: [6u8; 32] };
+        let pay_info1 = PayInfo { info: [6u8; 88] };
         let spend_vv = 1;
 
         let (payment1, _upd_wallet) = aggr_wallet
@@ -188,7 +188,7 @@ mod tests {
         .unwrap();
 
         // Let's try to spend some coins
-        let pay_info1 = PayInfo { info: [6u8; 32] };
+        let pay_info1 = PayInfo { info: [6u8; 88] };
         let spend_vv = 1;
 
         let (payment1, upd_wallet) = aggr_wallet
@@ -206,17 +206,16 @@ mod tests {
             .spend_verify(&params, &verification_key, &pay_info1)
             .unwrap());
 
-        let pay_info2 = PayInfo { info: [7u8; 32] };
-        let (payment2, _) = upd_wallet
-            .spend(
-                &params,
-                &verification_key,
-                &user_keypair.secret_key(),
-                &pay_info2,
-                false,
-                spend_vv,
-            )
-            .unwrap();
+
+        let pay_info2 = PayInfo { info: [7u8; 88] };
+        let (payment2, _) = upd_wallet.spend(
+            &params,
+            &verification_key,
+            &user_keypair.secret_key(),
+            &pay_info2,
+            false,
+            spend_vv,
+        ).unwrap();
 
         assert!(payment2
             .spend_verify(&params, &verification_key, &pay_info2)
@@ -284,7 +283,7 @@ mod tests {
         .unwrap();
 
         // Let's try to spend some coins
-        let pay_info1 = PayInfo { info: [6u8; 32] };
+        let pay_info1 = PayInfo { info: [6u8; 88] };
         let spend_vv = 1;
 
         let (payment1, _upd_wallet) = aggr_wallet
@@ -306,7 +305,7 @@ mod tests {
         let current_l = aggr_wallet.l.get();
         aggr_wallet.l.set(current_l - 1);
 
-        let pay_info2 = PayInfo { info: [7u8; 32] };
+        let pay_info2 = PayInfo { info: [7u8; 88] };
 
         let (payment2, _) = aggr_wallet
             .spend(
@@ -388,7 +387,7 @@ mod tests {
         .unwrap();
 
         // Let's try to spend some coins
-        let pay_info1 = PayInfo { info: [6u8; 32] };
+        let pay_info1 = PayInfo { info: [6u8; 88] };
         let spend_vv = 10;
 
         let (payment1, _) = aggr_wallet
@@ -410,17 +409,15 @@ mod tests {
         let current_l = aggr_wallet.l.get();
         aggr_wallet.l.set(current_l - 10);
 
-        let pay_info2 = PayInfo { info: [7u8; 32] };
-        let (payment2, _) = aggr_wallet
-            .spend(
-                &params,
-                &verification_key,
-                &user_keypair.secret_key(),
-                &pay_info2,
-                false,
-                spend_vv,
-            )
-            .unwrap();
+        let pay_info2 = PayInfo { info: [7u8; 88] };
+        let (payment2, _) = aggr_wallet.spend(
+            &params,
+            &verification_key,
+            &user_keypair.secret_key(),
+            &pay_info2,
+            false,
+            spend_vv,
+        ).unwrap();
 
         let identify_result =
             identify(payment1, payment2, pay_info1.clone(), pay_info2.clone()).unwrap();

common/nym_offline_compact_ecash/src/scheme/mod.rs

@@ -315,25 +315,24 @@ pub fn compute_kappa(
 
 #[derive(PartialEq, Eq, Debug, Clone)]
 pub struct PayInfo {
-    pub info: [u8; 32],
+    pub info: [u8; 88],
 }
 
-pub fn generate_payinfo(provider_pk: PublicKeyUser) -> Vec<u8>{
-    let mut rng = thread_rng();
-    let mut rbytes = [0u8; 32];
-    rng.fill(&mut rbytes);
+pub fn generate_payinfo(provider_pk: PublicKeyUser) -> PayInfo{
+    let mut info = [0u8; 88];
 
+    // Generating random bytes
+    thread_rng().fill(&mut info[..32]);
+
+    // Adding timestamp bytes
     let timestamp = Utc::now().timestamp();
-    let timestamp_bytes: [u8; 8] = timestamp.to_be_bytes();
+    info[32..40].copy_from_slice(&timestamp.to_be_bytes());
 
+    // Adding provider public key bytes
     let ppk_bytes = provider_pk.pk.to_affine().to_compressed();
+    info[40..].copy_from_slice(&ppk_bytes);
 
-    let mut payinfo = Vec::with_capacity(32 + 8 +48);
-    payinfo.extend_from_slice(&rbytes);
-    payinfo.extend_from_slice(&timestamp_bytes);
-    payinfo.extend_from_slice(&ppk_bytes);
-    
-    payinfo
+    PayInfo { info }
 }
 
 #[derive(Debug, Clone, PartialEq)]

common/nym_offline_compact_ecash/src/tests/e2e.rs

@@ -70,7 +70,7 @@ fn main() -> Result<(), CompactEcashError> {
     assert_eq!(aggr_wallet, wallet);
 
     // Let's try to spend some coins
-    let pay_info = PayInfo { info: [6u8; 32] };
+    let pay_info = PayInfo { info: [6u8; 88] };
     let spend_vv = 1;
 
     let (payment, _) = aggr_wallet.spend(