did:cow, a proposal for an ID resolution method with most of the convenience of did:plc/did:web and the robustness of a public blockchain
contract, undebugged
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CowRegistry.sol
+86
CowRegistry.sol
···
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contract CowRegistry {
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struct Cow {
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address controller;
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bytes12 prefix; // set to "did::" to deactivate
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string wrappedDID;
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}
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mapping(bytes32 => Cow) public cows;
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event CowInitialized(bytes32 indexed cowHash, address controller, bytes8 prefix, string wrappedDID);
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event CowDeactivated(bytes32 indexed cowHash);
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event ControllerUpdated(bytes32 indexed cowHash, address controller);
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event WrappedDIDUpdated(bytes32 indexed cowHash, bytes12 prefix, bytes wrappedDID);
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function updateWrappedDIDByHash(
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bytes32 cowHash,
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bytes12 prefix,
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string memory wrappedDID
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) public {
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require(cows[cowHash].prefix != bytes12("did::"));
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require(msg.sender == cows[cowHash].controller);
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require(prefix != bytes12("did::"), "Use deactivate() to deactivate");
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cows[cowHash].prefix = prefix;
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cows[cowHash].wrappedDID = wrappedDID;
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emit WrappedDIDUpdated(cowHash, prefix, wrappedDID);
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}
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function updateControllerByHash(
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bytes32 cowHash,
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address controller
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) public {
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require(cows[cowHash].prefix != bytes12("did::"));
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require(msg.sender == cows[cowHash].controller);
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cows[cowHash].controller = controller;
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emit ControllerUpdated(cowHash, controller);
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}
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function calculateCowHash(address controller, bytes12 prefix, string wrappedDID) public pure returns (bytes32 cowHash) {
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return keccak256(abi.encodePacked(controller, prefix, wrappedDID));
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}
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// Return a Cow struct for the settings, storing it if it was not already there
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function _ensureCowInitialized(address controller, bytes12 prefix, string wrappedDID) internal returns (bytes32 cowHash) {
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bytes32 cowHash = calculateCowHash(controller, prefix, wrappedDID);
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if (cows[cowHash].prefix == bytes12(0)) { // unregistered
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cows[cowHash] = Cow(
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controller,
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prefix,
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wrappedDID
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);
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emit CowInitialized(cowHash, controller, bytes12, prefix, wrappedDID);
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}
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return cowHash;
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}
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// You don't particularly need to call this, you can leave it until you make an update
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function initializeCow(address controller, bytes12 prefix, string wrappedDID) external {
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_ensureCowInitialized(address, prefix, wrappedDID);
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}
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function updateWrappedDID(address controller, bytes12 prefix, string wrappedDID, address newController) {
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bytes cowHash = _initializedCow(controller, prefix, wrappedDID);
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updateWrappedDIDByHash(cowHash, prefix, wrappedDID);
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}
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function updateController(address controller, bytes12 prefix, string wrappedDID, address newController) {
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bytes cowHash = _initializedCow(controller, prefix, wrappedDID);
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updateControllerByHash(cowHash, newController);
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}
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function deactivate(bytes32 cowHash) external {
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require(prefix != bytes12("did::");
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require(cows[cowHash].prefix != bytes12("did::"));
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require(msg.sender == cows[cowHash].controller);
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cows[cowHash].prefix = bytes12("did::");
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cows[cowHash].controller = address(0);
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emit DIDDeactivated(cowHash);
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}
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}