Recently, I’ve developed an interesting business using multi-sign wallet.

This project, requires tokens(ERC20) can be only minted by someone who approved by multiple administrators. I decided to implement those multi-approvals by administrators using multi-sign wallet.

1. First of all, there must be or we’re implementing a contarct for CRUDing to minters.

   contract AddressPrivileges {
       ...
       function addMinter(address _addMinter) public validCall returns (bool) {...}
       function delMinter(address _delMinter) public validCall returns (bool) {...}
       function isMinter(address account) public view returns (bool) {...}
       modifier onlyMinter() {...}
       ...
   }

2. Here is multiSignature.sol

   contract multiSignature {
       ...
       function createApplication(address to) external returns(uint256) {
           bytes32 msghash = getApplicationHash(msg.sender, to);
           uint256 index = signatureMap[msghash].length;
           signatureMap[msghash].push(signatureInfo(msg.sender, new address[](0)));
           emit CreateApplication(msg.sender, to, msghash);
           return index;
       }
       function signApplication(bytes32 msghash) external onlyOwner validIndex(msghash, defaultIndex) {
       emit SignApplication(msg.sender, msghash, defaultIndex);
       signatureMap[msghash][defaultIndex].signatures.addWhiteListAddress(msg.sender);
   }
   ...
   }

   When user clicks a button like add minter from FE, it calls multiSignature.sol:createApplication function first : createApplication(${address of AddressPrivileges contract}) to hashes the ${address of AddressPrivileges} and users address , put the hash into a signatureMap.

   Then administrators can see these pending approvals in their end.

   Once they all approved the request from their site, FE calls signApplication to add their address to the signatureMap.signatureInfo.signatures. (signatures[] is empty before signApplication function, it was a signatureMap[msghash] [empty] )

3. After approved by multi-sign wallets , now it’s fine to call addMinter in AddressPrivileges.sol, bcz we can’t pass the validCall check til multi-sign approval.

   modifier validCall() {
       checkMultiSignature();
       _;
   }

I would not say too much to breakdown those source codes wrote in my style , it’s not important , for now the matter is to get the mind.

Cool.

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