@hankolabs/attestation-engine

Ed25519 typed attestation issuer and verifier for the HANKO Solana Agent Trust Registry.

It ports the EIP-712 domain-separator pattern to Ed25519 so the resulting signature can be verified inside a Solana program via the Instructions sysvar. The same canonical byte layout is produced off-chain (this package) and hashed on-chain (the Anchor program), so a signature made here validates in post_attestation.

Install

npm install @hankolabs/attestation-engine

Canonical message layout

Byte-for-byte identical to the program's util.rs::canonical_attestation_message (125 bytes):

"hanko-attest"(12) || client(32) || agent(32) || score(i8) ||
tag_bitmap(u64 le) || uri_hash(32) || nonce(u64 le)

The domain separator is the fixed 12-byte ASCII prefix hanko-attest. The client (attester) is the Ed25519 signer.

Usage

import { PublicKey } from "@solana/web3.js";
import nacl from "tweetnacl";
import {
  signAttestation,
  verifyAttestation,
} from "@hankolabs/attestation-engine";

const client = nacl.sign.keyPair();

const params = {
  client: new PublicKey(client.publicKey),
  agent: new PublicKey("8N3v..."),
  score: 90,                 // i8, range [-100, 100]
  tagBitmap: 0b101n,         // u64 tag bitmap
  uriHash: new Uint8Array(32),
  nonce: 1n,
};

const signature = signAttestation(params, client.secretKey);
const ok = verifyAttestation(params, signature, new PublicKey(client.publicKey));

API

| Export | Description | | ------ | ----------- | | canonicalMessage(params) | Build the 125-byte canonical bytes that must be signed. | | signAttestation(params, secretKey) | Ed25519 sign the canonical message (64-byte nacl secret key). | | verifyAttestation(params, signature, clientPublicKey) | Verify a signature against its canonical message. | | validationCommitment(expectedHash, salt) | sha256(expected_hash \|\| salt) — the Validation Registry commitment. | | bs58Encode(bytes) / bs58Decode(text) | Base58 helpers. | | HANKO_ATTESTATION_DOMAIN | The 12-byte domain prefix constant. |

score outside [-100, 100] or a uriHash that is not exactly 32 bytes throws.

License

MIT