EthBridgeOptimized Code Style Findings

EBO-01C: Inexistent Error Message

Description:

The linked require check has no error message explicitly defined.

Example:

Copy
187require(sig.length == 65);

Recommendation:

We advise it to be set so to aid in the validation of the require's condition as well as the legibility of the codebase.

Alleviation:

A proper error message was introduced for the linked require instance.

EBO-02C: Redundant keccak256 Re-Execution

Description:

The linked statements perform the keccak256 operation on the same payload multiple times redundantly.

Example:

Copy
129function unlockTokens(
130    bytes32 messageHash,
131    bytes calldata message,
132    bytes[] calldata claimedSig
133) external {
134    if (txStore[keccak256(message)] == true) revert DoubleClaimDetected();
135    if (message.length <= 32) revert InvalidMessage();
136    (
137        uint256 amount,
138        uint256 _nonce,
139        uint32 chainID,
140        address to
141    ) = abi.decode(message, (uint256, uint256, uint32, address));
142    if (chainID !=block.chainid) revert InvalidChainID(chainID,uint32(block.chainid));
143    if (messageHash != prefixed(keccak256(message)))
144        revert HashMismatched(messageHash, prefixed(keccak256(message)));
145    //signature check
146    if (signaturesVerifier(claimedSig, messageHash) == true)
147        _unlockTokens(
148            amount,
149            _nonce,
150            chainID,
151            to,
152            keccak256(message)
153        );
154}

Recommendation:

We advise the operation to be performed once, stored in-memory and consequently utilized to optimize the code.

Alleviation:

The code has been optimized according to our recommendation caching the keccak256(message) operation.

EBO-03C: Suboptimal Conditionals

Description:

The linked conditionals negate a comparator and as such can be optimized by moving the negation to the comparator itself (i.e. !(a > 0) becomes (a <= 0) or (a == 0) if a is guaranteed to be positive).

Example:

Copy
111if (!(amount > 0)) revert ZeroAmount();

Recommendation:

We advise this to be done so to simplify the code and optimize its gas cost.

Alleviation:

The code was optimized only for the last linked instance thereby partially alleviating this exhibit.

EBO-04C: Variable Mutability Specifiers

Description:

The linked variables are assigned to only once during the contract's constructor.

Example:

Copy
48constructor(
49    address[] memory _validators,
50    address _ETHTOKEN,
51    address _owner,
52    uint256 _multiSigThreshold
53) {
54    if (_multiSigThreshold < 2)
55        revert ThresholdNotMet(_multiSigThreshold, 2);
56
57
58    threshold = _multiSigThreshold;
59    ETHTOKEN = _ETHTOKEN;
60    owner = _owner;
61
62
63    for (uint256 i = 0; i < _validators.length; i++) {
64        validators[_validators[i]] = true;
65    }
66}

Recommendation:

We advise them to be set as immutable greatly optimizing the codebase.

Alleviation:

Both linked variables were properly set as immutable optimizing the codebase.