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Remove Custom Metadata Signature Structure

Centralized Verification

NameService signatures are verified by Core.sol using validateAndConsumeNonce(). Uses NameServiceHashUtils.hashDataForRemoveCustomMetadata() for hash generation.

To authorize the removeCustomMetadata operation within the Name Service, the user who currently owns the username must generate a cryptographic signature compliant with the EIP-191 standard.

Signature Format​

{evvmId},{senderExecutor},{hashPayload},{originExecutor},{nonce},{isAsyncExec}

Hash Payload Generation​

import {NameServiceHashUtils} from "@evvm/testnet-contracts/library/signature/NameServiceHashUtils.sol";

bytes32 hashPayload = NameServiceHashUtils.hashDataForRemoveCustomMetadata(
    username,  // Username
    key        // Metadata key/index to remove
);
// Internal: keccak256(abi.encode("removeCustomMetadata", username, key))

Example​

Scenario: Owner wants to remove custom metadata from their username "alice"

string memory username = "alice";
uint256 key = 3;  // Metadata entry identifier

bytes32 hashPayload = NameServiceHashUtils.hashDataForRemoveCustomMetadata(username, key);

Message: 1,0x0000000000000000000000000000000000000000,0x[hashPayload],0x0000000000000000000000000000000000000000,15,true

Technical Details
  • Selective Removal: Removes a specific metadata entry by key
  • Owner-Only: Only current username owner can remove metadata
  • Hash Independence: Hash payload does NOT include executors (only username, key)
  • 3: The key/index of the specific metadata entry to remove
  • 15: The current username owner's nonce

This message would then be signed using EIP-191 standard, and the resulting signature would be used to verify the metadata removal request in the verifyMessageSignedForRemoveCustomMetadata function.

tip
  • The function selector 8adf3927 is the first 4 bytes of the keccak256 hash of the function signature for verifyMessageSignedForRemoveCustomMetadata
  • Strings.toString converts a number to a string (standard OpenZeppelin utility)
  • The signature verification uses the EIP-191 standard for message signing
  • Only the current owner of the username can remove custom metadata from their username
  • The _key parameter identifies which specific metadata entry to remove by its index/identifier
  • The _nonce parameter is the user's general nonce, not specifically the name service nonce