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Pre-registration of username Signature Structure

To authorize the preRegistrationUsername operation, the user (_user) must generate a cryptographic signature compliant with the EIP-191 standard.

The signature is created by signing a precisely formatted string message derived from the pre-registration details.

Signed Message Format​

The message is constructed by concatenating the following components as strings, separated by commas (,):

string.concat(
    "5d232a55",
    ",",
    AdvancedStrings.bytes32ToString(_hashUsername),
    ",",
    Strings.toString(_nameServiceNonce)
);

Message Components​

1. Function Selector (Hex String):

  • Value: 5d232a55
  • Purpose: Identifies the preRegistrationUsername function within the EIP-191 framework

2. Username Hash (String):

  • Value: The result of AdvancedStrings.bytes32ToString(_hashUsername)
  • Purpose: String representation of the bytes32 hash commitment being pre-registered

3. Name Service Nonce (String):

  • Value: The result of Strings.toString(_nameServiceNonce)
  • Purpose: Provides replay protection for pre-registration actions by the user

Example​

Here's a practical example of constructing a signature message for pre-registering a username:

Scenario: User wants to pre-register the username "alice" with a secret clowNumber

Parameters:

  • Username: "alice"
  • ClowNumber: 123456789 (secret value)
  • _hashUsername: keccak256(abi.encodePacked("alice", 123456789)) = 0xa1b2c3d4e5f6789abcdef123456789abcdef123456789abcdef123456789abcdef
  • _nameServiceNonce: 15

Resulting message string:

5d232a55,0xa1b2c3d4e5f6789abcdef123456789abcdef123456789abcdef123456789abcdef,15

Message breakdown:

  1. 5d232a55 - Function selector for preRegistrationUsername
  2. 0xa1b2c3d4e5f6789abcdef123456789abcdef123456789abcdef123456789abcdef - Hash of username and clowNumber
  3. 15 - Name Service nonce
tip
  • AdvancedStrings.bytes32ToString converts a bytes32 value to a lowercase hexadecimal string with "0x" prefix
  • Strings.toString converts a number to a string
  • The _hashUsername must be calculated as keccak256(abi.encodePacked(_username, _clowNumber))
  • The _clowNumber is a secret value that must be remembered for the registration step
  • The function selector 5d232a55 identifies this specific Name Service operation

Hash Username Structure​

For pre-registration of a username, users must provide a hash of the username. The hash is calculated using keccak256 with the following structure:

keccak256(abi.encodePacked(_username, _clowNumber));

Where:

  • _username is the desired username (string)
  • _clowNumber is the secret key number (uint256) that will be used in the registrationUsername function

Important: The _clowNumber must be kept secret during pre-registration and revealed during the actual registration process.