npm install attest-auth

const Authenticator = require('attest-auth')
const ed25519 = require('noise-curve-ed')
const secp256k1 = require('noise-curve-secp')

const keypair = ed25519.generateKeyPair()
const serverKeys = ed25519.generateKeyPair()

const server = new Authenticator(serverKeys, { curve: ed25519 })

let serverLogin = server.createServerLogin({
  timeout: 2 * 60 * 1000,
  description: 'Bitfinex'
})

serverLogin.on('verify', function () {
  console.log(serverLogin.publicKey.slice(0, 4).toString('hex'), 'logged in!')
})

const challengeInfo = serverLogin.getChallenge()

// User passes challenge somehow to auth device
const metadata = Buffer.from('put metadata here.')

const curve = [ed25519, secp256k1]
const trustedLogin = Authenticator.createClientLogin(keypair, serverKeys.pub, challengeInfo, { curve, metadata })

trustedLogin.on('verify', function (info) {
  console.log(info.publicKey.slice(0, 8), 'logged in!', info)
  console.log(Buffer.from(info.metadata, 'base64').toString()) // put metadata here.
})

// Verify the challenge using our local key pair
serverLogin = server.verify(trustedLogin.request, { metadata })

console.log(serverLogin.clientMetadata.toString()) // put metadata here.

// Pass the server response back so the trustedLogin knows it worked as well
trustedLogin.verify(serverLogin.response)

{
  curve  // specify curve to be used for dh, must be noise-handshake compliant
}

{
  curve,    // specify a curve/an array of curves to be used for dh, must be noise-handshake compliant
  metadata  // optional metadata to be passed as a buffer
}

{
  metadata  // optional metadata to be passed as a buffer
}

{
  type,
  publicKey,   // hex encoded public key
  description,
  metadata     // base64 encoded metadata
}