fix: update comments

contracts/contracts/paymasters/SignatureBasedPaymaster.sol

@@ -61,12 +61,14 @@ contract SignatureBasedPaymaster is IPaymaster, Ownable, EIP712 {
             );
             (uint lastTimestamp, bytes memory sig) = abi.decode(innerInputs,(uint256,bytes));
 
-            // Verify if token is the correct one
+            // Verify signature expiry based on timestamp. 
+            // Timestamp is used in signature hash, hence cannot be faked. 
             require(block.timestamp <= lastTimestamp, "Paymaster: Signature expired");
-            // We verify that the user has provided enough allowance
+            // Get user address from transaction.from
             address userAddress = address(uint160(_transaction.from));
+            // Generate hash
             bytes32 hash = keccak256(abi.encode(SIGNATURE_TYPEHASH, userAddress,lastTimestamp, nonces[userAddress]++));
-
+            // Hashing with domain separator includes chain id. Hence prevention to signature replay atttacks.
             bytes32 digest = _hashTypedDataV4(hash);
             require(signer == digest.recover(sig),"Paymaster: Invalid signer");
 

contracts/deploy/signatureBasedPaymaster.ts

@@ -23,7 +23,7 @@ export default async function (hre: HardhatRuntimeEnvironment) {
   const network = hre.userConfig.networks?.zkSyncTestnet;
   const provider = new Provider((network as HttpNetworkUserConfig).url);
 
-  // The wallet that will deploy the token and the paymaster
+  // The wallet that will deploy the paymaster
   // It is assumed that this wallet already has sufficient funds on zkSync
   const wallet = new Wallet(PRIVATE_KEY);
   const deployer = new Deployer(hre, wallet);

contracts/test/signatureBased.test.ts

@@ -39,7 +39,6 @@ describe("SignatureBasedPaymaster", function () {
     greeter = await deployContract(deployer, "Greeter", ["Hi"]);
     await fundAccount(wallet, paymaster.address, "3");
     console.log(`Paymaster current signer: ${signerWallet.address}`);
-    console.log("--------------------------------");
   });
 
   async function createSignatureData(
@@ -78,7 +77,7 @@ describe("SignatureBasedPaymaster", function () {
 
     const signature = await signer._signTypedData(domain, types, values);
 
-    console.log("Signature generated successfully !");
+    //console.log("Signature generated successfully !");
     //console.log("Signer : " + signer.address);
     //console.log("Paymaster : "+ paymaster.address);
     //console.log(`Signature valid till: ${lastTimestamp} for user: ${user.address} and nonce: ${nonce}`);