Commitment Relayer

Computes Poseidon commitment hashes server-side for clients that cannot run the Poseidon hash function locally.

Endpoint

POST /api/commitment/compute

Port: 3002
Public URL: https://relayer.specterchain.com/api/commitment/compute

Request

{
  "secret": "123456789",
  "nullifierSecret": "987654321",
  "blinding": "111222333",
  "tokenIdHash": "0",
  "amount": "1000000000000000000",
  "policyId": "0",
  "policyParamsHash": "0"
}

Field	Type	Required	Description
secret	string	Yes	User's private key (as decimal string)
nullifierSecret	string	Yes	Nullifier secret (as decimal string)
blinding	string	Yes	Random blinding factor (as decimal string)
tokenIdHash	string	Yes	Token ID hash ("0" for native GHOST)
amount	string	Yes	Amount in aghost (as decimal string)
policyId	string	No	Policy contract address ("0" if none)
policyParamsHash	string	No	Policy params hash ("0" if none)

Response

{
  "commitment": "0x1a2b3c4d..."
}

Authentication

Requires HMAC signature in the request header:

X-HMAC-Signature: <computed-hmac>

Rate limit

10 requests/minute/IP

Health check

GET /health

Security note

warning

The commitment relayer receives your secret and nullifierSecret in plaintext. If you're concerned about the relayer operator seeing these values, compute the Poseidon hash client-side using circomlibjs instead.

import { buildPoseidon } from 'circomlibjs';
const poseidon = await buildPoseidon();
const commitment = poseidon([secret, nullifierSecret, tokenIdHash, amount, blinding]);