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Accept Offer Signature Structure

Centralized Verification

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

To authorize the acceptOffer operation within the Name Service, the user who currently owns the username must generate a cryptographic signature compliant with the EIP-191 standard using the Ethereum Signed Message format.

Signature Format​

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

Hash Payload Generation​

The hashPayload is generated using NameServiceHashUtils.hashDataForAcceptOffer():

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

bytes32 hashPayload = NameServiceHashUtils.hashDataForAcceptOffer(
    username,  // Username being sold
    offerID    // ID of the offer to accept
);

// Internal implementation
// keccak256(abi.encode("acceptOffer", username, offerID))

Example​

Scenario: Current owner of username "alice" wants to accept an offer

string memory username = "alice";
uint256 offerID = 123;

bytes32 hashPayload = NameServiceHashUtils.hashDataForAcceptOffer(username, offerID);

Message: 1,0x0000000000000000000000000000000000000000,0x[hashPayload],0x0000000000000000000000000000000000000000,3,true

Technical Details
  • Hash Independence: The hash payload does NOT include executors (only username, offerID)
  • Operation Name: "acceptOffer" is included in hash via NameServiceHashUtils
  • Ownership Transfer: Accepting an offer transfers username ownership to the offeror
  • Owner-Only: Only the current username owner can accept offers
  • Authorization: Only the current owner of the username can accept offers
  • Offer Validation: _offerId must correspond to a valid, non-expired offer
  • Ownership Transfer: Accepting an offer transfers username ownership to the offeror
  • Replay Protection: _nameServiceNonce prevents replay attacks
  • EVVM ID: Identifies the specific EVVM instance for signature verification

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