Universal Module of X.509 Certificate Utilities in JavaScript

WARNING: At this time this solution should be considered suitable for research and experimentation, further code and security review is needed before utilization in a production application.

Introduction and Overview

This library is designed to be 'universal' as a utility to handle X.509 in JavaScript, i.e., it works both on most browsers and on Node.js just by importing from npm/source code. This library provides APIs to convert between Json Web Key (JWK) and X.509 DER/PEM.

Installation

At your project directory, do either one of the following.

• From npm/yarn:

  $ npm install --save js-x509-utils // npm
  $ yarn add js-x509-utils // yarn

• From GitHub:

  $ git clone https://github.com/junkurihara/jscu.git
  $ cd js-crypto-utils/packages/js-x509-utils
  & yarn build

Then you should import the package as follows.

import x509 from 'js-x509-utils'; // for npm
import x509 from 'path/to/js-x509-utils/dist/index.js'; // for github

The bundled file is also given as js-x509-utils/dist/x509.bundle.js for a use case where the module is imported as a window.x509 object via script tags.

Usage

This library always uses JWK-formatted keys (RFC7517) to do any operations. If you utilize keys of other format, like PEM, please use js-crypto-key-utils to convert them to JWK.

Create X.509 from JWK-formatted public key

ECDSA

const publicJwk = {kty: 'EC', crv: 'P-256', x: '...', y: '...'}; // public key to be signed
const privateJwk = {ktyp: 'EC', crv: 'P-256', x: '...', y: '...', d: '...'}; // private key

const name = { // this is optional
      countryName: 'JP',
      stateOrProvinceName: 'Tokyo',
      localityName: 'Chiyoda',
      organizationName: 'example',
      organizationalUnitName: 'Research',
      commonName: 'example.com'
    };

// sign
x509.fromJwk(
  publicJwk,
  privateJwk,
  'pem',
  {
    signature: 'ecdsa-with-sha256', // signature algorithm
    days: 365, // expired in days
    issuer: name, // issuer
    subject: name // assume that issuer = subject, i.e., self-signed certificate
  },
  'pem' // output signature is in PEM. DER-encoded signature is available with 'der'.
).then( (cert) => {
  // now you get the certificate in PEM string
});

RSA-PSS

const publicJwk = {kty: 'RSA', n: '...', e: '...'}; // public key to be signed
const privateJwk = {ktyp: 'RSA', n: '...', e: '...', d: '...', p: '...', q: '...', ...}; // private key

const name = {
  countryName: 'JP',
  stateOrProvinceName: 'Tokyo',
  localityName: 'Chiyoda',
  organizationName: 'example',
  organizationalUnitName: 'Research',
  commonName: 'example.com'
};

x509.fromJwk(
  publicJwk,
  privateJwk,
  'pem',
  {
    signature: 'rsassaPss',
    days: 365,
    issuer: name,
    subject: name,
    pssParams: {
      saltLength: 32, // if unspecified, 20 will be applied as default value
      hash: 'SHA-256' // if unspecified, 'SHA-1' will be applied as default value (but I do not not recommend SHA-1)
    }
  }
).then( (crt) => {
  // now you get a certificate
});

RSASSA-PKCS1-v1_5

const publicJwk = {kty: 'RSA', n: '...', e: '...'}; // public key to be signed
const privateJwk = {ktyp: 'RSA', n: '...', e: '...', d: '...', p: '...', q: '...', ...}; // private key

const name = {
  countryName: 'JP',
  stateOrProvinceName: 'Tokyo',
  localityName: 'Chiyoda',
  organizationName: 'example',
  organizationalUnitName: 'Research',
  commonName: 'example.com'
};

x509.fromJwk(
  publicJwk,
  privateJwk,
  'pem',
  {
    signature: 'sha256WithRSAEncryption',
    days: 365,
    issuer: name,
    subject: name
  }
).then( (crt) => {
  // now you get a certificate
});

Extract JWK from X.509 certificate

const crtsample = '-----BEGIN CERTIFICATE-----...';
const jwkey = x509.toJwk(crtsample, 'pem');
// now you get JWK public key from PEM-formatted certificate

Extract signature and message body from X.509 certificate

const crtsample = '-----BEGIN CERTIFICATE-----...';
const parsed = x509.parse(crtsample, 'pem');
// now you get parsed object from PEM-formatted certificate
// {tbsCertificate, signatureValue, signatureAlgorithm}

Note

Limitations

Legacy IE is NOT supported at all. Also the followings are not supported in Edge.

• ECDSA: ecdsa-with-sha1
• RSASSA-PKCS-v1_5: Sha1WithRsaEncryption
• RSA-PSS: All

Note that referring to RFC, Sha1WithRsaEncryption is the default algorithm when empty params for RSA-SSA-PKCS-v1_5, and hence MS environment does not support such existing certificates. Hence we strongly recommend to use other modern browsers.

ECDSA

At this point, this library supports only certificate signed with ECDSA using the following curve for elliptic curve cryptography.

• P-256 (secp256r1)
• P-384 (secp384r1)
• P-521 (secp521r1)
• P-256K (secp256k1)

License

Licensed under the MIT license, see LICENSE file.