Bridge Cosigner Manager

In order to provide anti-fraud protection, the cosigner manager is developed for. It check on validity of enter result, verify correct signatures of syndicate on chain and it's uniqueness. In order to be a successfull transaction at exit function, it should have more than 66% of votes collected from cosigners and which is called syndicate.

Base functionality

The core and important logic for bridge cosigner manager

Cosigner

struct Cosigner {
    address addr;
    uint256 chainId;
    uint256 index;
    bool active;
}

• Should not be a zero to prevent unexpected behaviour;
• Should represent for what chain it specific for;
• Could be deactivate in case of compromise;

addCosigner

function addCosigner(address cosaddr, uint256 chainId) external;

• Allows only SAO to execute;
• Should not add already existing cosigner on anychain (unique in mature);
• Could not be zero address;
• Could not add cosigner for local chain, only remote chains;

removeCosigner

function removeCosigner(address cosaddr) external;

• Allows only SAO to execute;
• Should remove if it exists;
• Could not be zero address;

getCosigners

function getCosigners(uint256 chainId)
    external
    view
    returns (address[] memory);

• Should return active cosigners list for specific chain;
• Should not return cosigners for local chain;

getCosignCount

function getCosignCount(uint256 chainId) external view returns (uint8);

• Should return the number of cosigners required to proof the enter validity;
• Always must be more then 66% of existing cosigners;

verify

function verify(
    bytes32 commitment,
    uint256 chainId,
    bytes[] calldata signatures
) external view returns (bool);

• Should be used in exit function as basically designed for it;
• Signatures should not be equal and function must protect from this;
• Always verify external chain id;