README

secp256k1-node

This module provides native bindings to ecdsa secp256k1 functions. This library is experimental, so use at your own risk. Works on node version 0.10 or greater and in the Browser via browserify.

Installation

If you have gmp installed secp256k1 will use it. Otherwise it should fallback to OpenSSL.

arch pacman -S gmp
ubuntu sudo apt-get install libgmp-dev

from npm

npm install secp256k1

from git

git clone git@github.com:cryptocoinjs/secp256k1-node.git
cd secp256k1-node
git submodule init
git submodule update
npm install

Usage

var crypto = require('crypto')
var secp256k1 = require('secp256k1')
// or require('secp256k1/js')
//   if you want to use pure js implementation in node

// generate message to sign
var msg = crypto.randomBytes(32)

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

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

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

// verify the signature
console.log(secp256k1.verify(msg, sigObj.signature, pubKey))

* .verify return false for high signatures

* ECDH is not be available while bitcoin/secp256k1#352 not resolved. Right now you can use next code:

var BN = require('secp256k1/lib/js/bn')
var ECPoint = require('secp256k1/lib/js/ecpoint')
var d = BN.fromBuffer(privateKey)
var Q = ECPoint.fromPublicKey(publicKey)
return Q.mul(d).toPublicKey(true)

Elliptic vs "embedded"

secp256k1-node has pure JavaScript implementation secp256k1 based on elliptic, bn.js, hash.js. The main purpose of this implementation is more high performance, smaller size and simple code audit.

Code size:

	browserifiable	+ uglified	+ gzipped
elliptic	303555	211777	62124
embedded	241829	152989	35908
diff	25%	38%	73%

Performance:

$ node benchmark/benchmark.js
Set seed: 5120779d9d961dc818363811b3cf44ace2323ccf5e265749206d37442a0deac5
100% (1000/1000), 2.8s elapsed, eta 0.0s
Create 1000 fixtures
++++++++++++++++++++++++++++++++++++++++++++++++++
Benchmarking: publicKeyCreate
--------------------------------------------------
bindings x 13,945 ops/sec ±0.76% (101 runs sampled)
secp256k1js x 967 ops/sec ±0.41% (100 runs sampled)
elliptic x 838 ops/sec ±0.66% (99 runs sampled)
==================================================
Benchmarking: sign
--------------------------------------------------
bindings x 8,219 ops/sec ±0.13% (102 runs sampled)
secp256k1js x 773 ops/sec ±0.47% (98 runs sampled)
elliptic x 615 ops/sec ±0.43% (97 runs sampled)
==================================================
Benchmarking: verify
--------------------------------------------------
bindings x 5,350 ops/sec ±0.11% (103 runs sampled)
secp256k1js x 208 ops/sec ±0.19% (91 runs sampled)
elliptic x 131 ops/sec ±2.05% (87 runs sampled)
==================================================

LICENSE

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

secp256k1.js

Usage no npm install needed!