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Renew Username Signature Structure

To authorize the renewUsername operation within the MNS service, the user who currently owns the username must generate a cryptographic signature compliant with the EIP-191 standard.

This signature proves the current username owner's intent and authorization to extend the expiration period for their specified username (_username), typically involving a renewal fee.

Signed Message Format​

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

string.concat(
  "35723e23",
   ",",
   _username,
   ",",
   Strings.toString(_nameServiceNonce)
)

1. MNS Renew Username Identifier (Hex String):

  • Value: 35723e23
  • Purpose: A specific identifier used within the EIP-191 framework to distinguish MNS renewUsername messages from other types of signed messages.

2. Target Username (String):

  • Value: The _username string itself.
  • Purpose: Specifies the username whose registration the owner is requesting to renew.

3. MNS Nonce (String):

  • Value: The result of Strings.toString(_nameServiceNonce).
  • Purpose: The string representation of the current username owner's nonce specific to the MNS contract for this renewUsername action. This prevents replay attacks of the renewal operation initiated by the owner.

Practical Example​

Let's say the current owner wants to renew their username with the following parameters:

  • Username to Renew: "alice"
  • Name Service Nonce: 8

The message would be constructed as:

"35723e23,alice,8"

Message Breakdown:

  • 35723e23: Function selector for renew username verification
  • alice: The username that the current owner wants to renew
  • 8: The current username owner's name service nonce

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

tip
  • The function selector 35723e23 is the first 4 bytes of the keccak256 hash of the function signature for verifyMessageSignedForRenewUsername
  • 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 renew their own username
  • Renewal typically extends the username's expiration period and may involve a renewal fee