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Flush Username Signature Structure

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

This signature proves the current username owner's intent and authorization to permanently delete their username registration and all associated data from the MNS service. This is an irreversible action.

Signed Message Format​

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

string.concat(
   "044695cb",
   ",",
   _username,
   ",",
   Strings.toString(_nonce)
)

1. MNS Flush Username Identifier (Hex String):

  • Value: 044695cb
  • Purpose: A specific identifier used within the EIP-191 framework to distinguish MNS flushUsername messages from other types of signed messages.

2. Target Username (String):

  • Value: The _username string itself.
  • Purpose: Specifies the username registration that the owner is authorizing to be permanently flushed and deleted from the system.

3. MNS Nonce (String):

  • Value: The result of Strings.toString(_nonce).
  • Purpose: The string representation of the current username owner's nonce specific to the MNS contract for this flushUsername action. This prevents replay attacks of the irreversible deletion operation.

Practical Example​

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

  • Username: "alice"
  • Nonce: 25

The message would be constructed as:

"044695cb,alice,25"

Message Breakdown:

  • 044695cb: Function selector for flush username verification
  • alice: The username that will be permanently deleted
  • 25: 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 username deletion request in the verifyMessageSignedForFlushUsername function.

⚠️ Warning: This operation is irreversible and will permanently delete the username registration and all associated data.

tip
  • The function selector 044695cb is the first 4 bytes of the keccak256 hash of the function signature for verifyMessageSignedForFlushUsername
  • 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 flush their own username
  • This operation is irreversible and permanently deletes the username registration and all associated data
  • The _nonce parameter is the user's general nonce, similar to other deletion operations