JarCastingUniversal 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/js-x509-utils.git
Then you should import the package as follows.
import x509 from 'js-x509-utils'; // for npm
import x509 from 'js-x509-utils/dist/index.js'; // for github
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',
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)
days: 365,
issuer: name,
subject: name
}
).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
Due to the lack of native implementations of some primitive algorithms, the following signing algorithms do not work in legacy IE11.
- ECDSA:
ecdsa-with-sha1andecdsa-with-sha512 - RSASSA-PKCS-v1_5:
Sha1WithRsaEncryptionandSha512WithRsaEncryption - RSA-PSS: 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.