openac-rsa-x509-js

Node.js bindings for proving and verifying RSA X.509 certificate chains with the OpenAC Spartan2 circuits.

Introduction

This package wraps the wasm bindings built from the RSA-X.509-Cert branch of zkID, exposing prove / verify / load_pk and related circuit helpers to Node.js.

Installation

npm add https://github.com/privacy-ethereum/openac-rsa-x509-js

or add it directly to package.json:

{
  "dependencies": {
    "openac-rsa-x509": "github:privacy-ethereum/openac-rsa-x509-js"
  }
}

After installing, fetch the wasm assets (witness calculators + the spartan2 wasm module) and, if you intend to prove/verify, the proving and verifying keys:

npx --package=openac-rsa-x509 -- node node_modules/openac-rsa-x509/scripts/fetch-assets.mjs
npx --package=openac-rsa-x509 -- node node_modules/openac-rsa-x509/scripts/fetch-proving-keys.mjs

(When developing inside this repo, use npm run fetch:assets and npm run fetch:keys instead.)

Usage

import { init, load_pk, prove, verify, CircuitKind } from 'openac-rsa-x509';

await init();

// Load the proving key for the circuit you're using.
const pkBytes = await readFile('cert_chain_rs2048_proving.key');
await load_pk(CircuitKind.CertChainRs2048, pkBytes);

// witnessBytes is a `.wtns` binary produced by the matching Circom witness
// calculator (see assets/witness_calculator.js) for your circuit inputs.
const { proof, public_values } = await prove(CircuitKind.CertChainRs2048, witnessBytes);

// Verify with the matching verifying key.
const vkBytes = await readFile('cert_chain_rs2048_verifying.key');
const { valid } = await verify(new Uint8Array(proof), vkBytes);

CircuitKind has three variants: CertChainRs2048, CertChainRs4096, and UserSigRs2048. See test/ for full end-to-end examples (witness generation → prove → verify) for each circuit.

Other exports

• build_split_inputs(...) — build split circuit inputs from raw cert / signature material.
• cert_modulus_bits(certDer) — RSA modulus bit width of a DER-encoded cert.
• cert_serial_hex(certDer) — trimmed-hex serial of a DER-encoded cert.
• link_verify(certPubs, userSigPubs) — assert pk_commit equality between a cert-chain proof's public values and a user-sig proof's public values.

All functions other than init() require init() to have been called first.

Development

git clone https://github.com/privacy-ethereum/openac-rsa-x509-js
cd openac-rsa-x509-js
npm install
npm run fetch:assets
npm run fetch:keys
npm test

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.