Function: depositERC20(address _token, address _realSender, bytes _to, uint256 _amount, uint256 _gasLimit, uint256 _keyId)

This function deposits some token to a recipient's account on Cloak on behalf of the _realSender. The caller pays the tokens and needs to attach ETH to pay for the relayer fee, while the refunded ETH is sent to the _realSender.

Inputs

• _token

  • Control: Fully controlled by the caller.

  • Constraints: Must be an ERC-20 token with metadata.

  • Impact: The deposited token address on Scroll.

• _realSender

  • Control: Fully controlled by the caller.

  • Constraints: Must be able to receive ETH refunds.

  • Impact: The address of the real sender on Scroll.

• _to

  • Control: Fully controlled by the caller.

  • Constraints: N/A.

  • Impact: The encrypted address of the recipient on Cloak.

• _amount

  • Control: Fully controlled by the caller.

  • Constraints: Must be greater than zero.

  • Impact: The amount of tokens to transfer.

• _gasLimit

  • Control: Fully controlled by the caller.

  • Constraints: Must be lower than the maxGasLimit specified in the contract SystemConfig.

  • Impact: The gas limit required to complete the deposit on Cloak.

• _keyId

  • Control: Fully controlled by the caller.

  • Constraints: Must be the latest key ID stored in the contract ScrollChainValidium.

  • Impact: The encryption-key ID of the key used to encrypt the address of the recipient.

Branches and code coverage

Intended branches

• Emits a QueueTransaction event when the deposit is successful.

  Test coverage

• The _token balance of the caller decreases by _amount.

  Test coverage

• Adjusts, for fee-on-transfer tokens, the amount based on the actual received tokens.

  Test coverage

Negative behavior

• Reverts if trying to reenter the function.

  Negative test

• Reverts if the _keyId is not the latest.

  Negative test

• Reverts if the amount of _token received by the contract is zero.

  Negative test

• Reverts if there is insufficient value to pay for the relayer fee.

  Negative test

• Reverts if the _token does not have metadata.

  Negative test

• Reverts if the symbol and name functions of the _token return data of type bytes32.

  Negative test

Function call analysis

• this._deposit(_token, _realSender, _to, _amount, new bytes[0], _gasLimit, _keyId) -> this._transferERC20In(this._msgSender(), _token, _amount) -> SafeERC20Upgradeable.safeTransferFrom(IERC20Upgradeable(_token), _from, address(this), _amount)

  • What is controllable? _token, _from, and _amount.

  • If the return value is controllable, how is it used and how can it go wrong? N/A.

  • What happens if it reverts, reenters or does other unusual control flow? There are no changes to the state variables before this transfer, so reentry does not matter.

• this._deposit(_token, _realSender, _to, _amount, new bytes[0], _gasLimit, _keyId) -> IL1ScrollMessenger(this.messenger).sendMessage{value: msg.value}(this.counterpart, 0, _message, _gasLimit, _from)

  • What is controllable? _message, _gasLimit, and _from.

  • If the return value is controllable, how is it used and how can it go wrong? N/A.

  • What happens if it reverts, reenters or does other unusual control flow? N/A.