secp256k1-node

This module provides native bindings to bitcoin-core/secp256k1. In browser elliptic will be used as fallback.

Works on node version 10.0.0 or greater, because use N-API.

Installation

from npm

npm install secp256k1

from git

git clone [email protected]:cryptocoinjs/secp256k1-node.git
cd secp256k1-node
git submodule update --init
npm install

Windows

The easiest way to build the package on windows is to install windows-build-tools.

Or install the following software:

• Git: https://git-scm.com/download/win
• nvm: https://github.com/coreybutler/nvm-windows
• Python 2.7: https://www.python.org/downloads/release/python-2712/
• Visual C++ Build Tools: http://landinghub.visualstudio.com/visual-cpp-build-tools (Custom Install, and select both Windows 8.1 and Windows 10 SDKs)

And run commands:

npm config set msvs_version 2015 --global
npm install npm@next -g

Based on:

• nodejs/node-gyp#629 (comment)
• nodejs/node-gyp#972

Usage

• API Reference (v4.x) (current version)
• API Reference (v3.x)
• API Reference (v2.x)

Private Key generation, Public Key creation, signature creation, signature verification

const { randomBytes } = require('crypto')
const secp256k1 = require('secp256k1')
// or require('secp256k1/elliptic')
//   if you want to use pure js implementation in node

// generate message to sign
// message should have 32-byte length, if you have some other length you can hash message
// for example `msg = sha256(rawMessage)`
const msg = randomBytes(32)

// generate privKey
let privKey
do {
  privKey = randomBytes(32)
} while (!secp256k1.privateKeyVerify(privKey))

// get the public key in a compressed format
const pubKey = secp256k1.publicKeyCreate(privKey)

// sign the message
const sigObj = secp256k1.ecdsaSign(msg, privKey)

// verify the signature
console.log(secp256k1.ecdsaVerify(sigObj.signature, msg, pubKey))
// => true

* .verify return false for high signatures

Get X point of ECDH

const { randomBytes } = require('crypto')
// const secp256k1 = require('./elliptic')
const secp256k1 = require('./')

// generate privKey
function getPrivateKey () {
  while (true) {
    const privKey = randomBytes(32)
    if (secp256k1.privateKeyVerify(privKey)) return privKey
  }
}

// generate private and public keys
const privKey = getPrivateKey()
const pubKey = secp256k1.publicKeyCreate(getPrivateKey())

// compressed public key from X and Y
function hashfn (x, y) {
  const pubKey = new Uint8Array(33)
  pubKey[0] = (y[31] & 1) === 0 ? 0x02 : 0x03
  pubKey.set(x, 1)
  return pubKey
}

// get X point of ecdh
const ecdhPointX = secp256k1.ecdh(pubKey, privKey, { hashfn }, Buffer.alloc(33))
console.log(ecdhPointX.toString('hex'))

LICENSE

This library is free and open-source software released under the MIT license.