Unnecessary domainSeparator field in Request

[raullaprida]

The domainSeparator allows dApp developers be guaranteed that there can be no signature collision between multiple DApps.
Having said that, there's no need to include it as part of the Relay Data of the Request

Right now the included domainSeparator is only used on the signature verification, the RIF Relay system is not filtering nor registering specific domains (which could be used to allowing only specific registered domainSeparators to participate on RIF Relay). The specific SmartWallet Template in use for the invoked SmartWallet instance is the one that knows what domainSeparator to accept
For that reason, including the domainSeparator on the request is only making the relay call more expensive.

The default SmartWallet template included in our repo already has all the information to calculate the domainSeparator as a constant value:

require( keccak256(abi.encode( keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"), keccak256("RSK Enveloping Transaction"), //DOMAIN_NAME DATA_VERSION_HASH, getChainID(), address(this))) == domainSeparator, "Invalid domain separator" );

Once the domainSeparator attribute is removed from the request, this verification can be deleted. That won't affect the signature verification

require( RSKAddrValidator.safeEquals( keccak256(abi.encodePacked( "\x19\x01", domainSeparator, keccak256(_getEncoded(suffixData, req))) ).recover(sig), req.from), "signature mismatch" );

We just need to replace domainSeparator attribute which was received as an input parameter with the constant value that we already know:

bytes32 private constant domainSeparator = keccak256(abi.encode( keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"), keccak256("RSK Enveloping Transaction"), //DOMAIN_NAME DATA_VERSION_HASH, getChainID(), address(this)))

Just in case background information regarding EIP712 and how to use it is needed, I leave a link to a medium article from Metamask on how to use EIP712

[mortelli]

PP-137