eckeyUtils

Node.js based EC key utilities to generate the PEM contents (required by crypto.Sign and crypto.Verify) from the raw keys generated by crypto.ECDH and to parse key info from given PEM content. The lastest update has added JWK support.

Motivation

Namely the ECDH.generateKeys function should be used to generate EC keys for the key-exchange purpose, but actually the keys it generates are bare/raw ec private key (i.e., d in the cryptographic context) and ec public key (the relevant EC point, calculated from base point G and d), so supposedly there's no obstacle to use it in ECSDA scenario except that the crypto.Sign and crypto.Verify function doesn't support using raw key directly. This library comes out to bridge this gap by converting raw keys to PEM keys.

On the other side, this library provides a symmetrical function to parse key info (private key PEM -> {privateKey, curveName, publicKey?}, public key PEM -> {curveName, publicKey}) from the given EC PEM content, and such information can be used by crypto.ECDH.

P.s., the latest update: added JWK support - generation and parse.

CAUTION

Some people argue that use one key pair for both ECDH and ECDSA will compromise the security, so please try to avoid using one key pair for both usages except that you know dearly that there's no negative byeffect.

Usage

Generate PEM from raw keys

const crypto = require('crypto'), ecKeyUtils = require('eckey-utils');
const curveName = 'secp256k1';

const ecdh = crypto.createECDH(curveName);
ecdh.generateKeys();

const pems = ecKeyUtils.generatePem({
	curveName,
	privateKey: ecdh.getPrivateKey(),
	publicKey: ecdh.getPublicKey()
});

const sign = crypto.createSign('sha256');
const message = Buffer.from('Hello, World!');
sign.update(message);
let sig = sign.sign(pems.privateKey);

const verify = crypto.createVerify('sha256');
verify.update(message);
console.log(verify.verify(pems.publicKey, sig));

Parse key information from PEM

const ecKeyUtils = require('eckey-utils');

console.log(ecKeyUtils.parsePem(`-----BEGIN EC PRIVATE KEY-----
MIHcAgEBBEIBL1+Q5pDjC9ijZg/XCBhaJrV8pM+v/XgcwC53sWRFK69paB9zzVAD
ZqzrgXOAghxqWx0QEG8RhvXowXzMOuLmHz2gBwYFK4EEACOhgYkDgYYABAAlLIp1
uSSj9wjrpr4+9UitBXtEwB5AAS/PHyK/FLvM0Ybz0PDeg8RTqKXJziwz0i0AjvWp
FQSyuJe5PXesKhRzXQDqJQTijoekz5mWOdYLRnKln0B87JrXbpx+R0slrEJzPeHo
7fv+DaM09Dfvy30CLHhzaGqRpesz+rvPVKYCyun8EQ==
-----END EC PRIVATE KEY-----`));

console.log(ecKeyUtils.parsePem(`-----BEGIN PUBLIC KEY-----
MD4wEAYHKoZIzj0CAQYFZysBBAkDKgAEgiGotjsUDWG11VFfkBsSoscOvrH27hjw
6bHXZwpyLjXW19Th2MRYGg==
-----END PUBLIC KEY-----`));

Dependencies

Node.js version later than 5.x

License

Written in 2018 by tibetty [e-mail]