Implement EIP-1271 (Signature Validation)

[jacque006]

Problem

Currently, it is difficult for a dApp to verify BLS signed messages done by our client library/extension. They must implement custom logic.

Possible Solution

EIP-1271 provides a common interface that allows a contract to validate a signature. We could implement it by:

• Add new validate signature function to VerificationGateway.sol that can verify a BLS signed message.
• Implement ERC1271 spec on BLSWallet.sol, using the new signature validation function above.

This creates tight coupling between the wallet and gateway, which could be undesirable.

[jzaki]

Related -> https://ethereum-magicians.org/t/erc-4337-account-abstraction-via-entry-point-contract-specification/7160/68

[JohnGuilding]

Completed in #561