Gatekeepers Smart Contract

MACI requires a signup gatekeeper to ensure that only designed users register. It is up to MACI's deployer how they wish to allow sign-ups, therefore they can implement their own GateKeeper. The repository comes with different options:

• FreeForAllSignUpGatekeeper - This allows anyone to signup on MACI.
• SignUpTokenGatekeeper - This makes use of a ERC721 token to gatekeep the signup function.
• EASGatekeeper - This allows gatekeeping signups to only users who have a specific EAS attestation.
• HatsGatekeeper - This allows gatekeeping signups to only users who have a specific Hat.
• GitcoinPassportGatekeeper - This allows gatekeeping signups to only users who have a specific Gitcoin Passport score.

An abstract contract to inherit from is also provided, with two function signatures as shown below:

abstract contract SignUpGatekeeper {
    function setMaciInstance(MACI _maci) public virtual {}
    function register(address _user, bytes memory _data) public virtual {}
}

The MACI contract will need to call the SignUpGatekeeper.register function inside the MACI.signUp function.