JWA implementation (supports all JWS algorithms)


A JSON Web Algorithms implementation focusing (exclusively, at this point) on the algorithms necessary for JSON Web Signatures.

This library supports all of the required, recommended and optional cryptographic algorithms for JWS:

alg Parameter ValueDigital Signature or MAC Algorithm
HS256HMAC using SHA-256 hash algorithm
HS384HMAC using SHA-384 hash algorithm
HS512HMAC using SHA-512 hash algorithm
RS256RSASSA using SHA-256 hash algorithm
RS384RSASSA using SHA-384 hash algorithm
RS512RSASSA using SHA-512 hash algorithm
ES256ECDSA using P-256 curve and SHA-256 hash algorithm
ES384ECDSA using P-384 curve and SHA-384 hash algorithm
ES512ECDSA using P-521 curve and SHA-512 hash algorithm
noneNo digital signature or MAC value included


In order to run the tests, a recent version of OpenSSL is required. **The version that comes with OS X (OpenSSL 0.9.8r 8 Feb

  1. is not recent enough**, as it does not fully support ECDSA keys. You'll need to use a version > 1.0.0; I tested with OpenSSL 1.0.1c 10 May 2012.


To run the tests, do

$ npm test

This will generate a bunch of keypairs to use in testing. If you want to generate new keypairs, do make clean before running npm test again.

I spawn openssl dgst -sign to test OpenSSL sign → JS verify and openssl dgst -verify to test JS sign → OpenSSL verify for each of the RSA and ECDSA algorithms.


Creates a new jwa object with sign and verify methods for the algorithm. Valid values for algorithm can be found in the table above ('HS256', 'HS384', etc) and are case-insensitive. Passing an invalid algorithm value will throw a TypeError.

Sign some input with either a secret for HMAC algorithms, or a private key for RSA and ECDSA algorithms.

If input is not already a string or buffer, JSON.stringify will be called on it to attempt to coerce it.

For the HMAC algorithm, secretOrPrivateKey should be a string or a buffer. For ECDSA and RSA, the value should be a string represented a PEM encoded private key.

Output base64url formatted. This is for convenience as JWS expects the signature in this format. If your application needs the output in a different format, please open an issue. In the meantime, you can use brianloveswords/base64url to decode the signature.

Verify a signature. Returns true or false.

signature should be a base64url encoded string.

For the HMAC algorithm, secretOrPublicKey should be a string or a buffer. For ECDSA and RSA, the value should be a string represented a PEM encoded public key.



const jwa = require('jwa');
const hmac = jwa('HS256');
const input = 'super important stuff';
const secret = 'shhhhhh';
const signature = hmac.sign(input, secret);
hmac.verify(input, signature, secret) // === true 
hmac.verify(input, signature, 'trickery!') // === false 

With keys

const fs = require('fs');
const jwa = require('jwa');
const privateKey = fs.readFileSync(__dirname + '/ecdsa-p521-private.pem');
const publicKey = fs.readFileSync(__dirname + '/ecdsa-p521-public.pem');
const ecdsa = jwa('ES512');
const input = 'very important stuff';
const signature = ecdsa.sign(input, privateKey);
ecdsa.verify(input, signature, publicKey) // === true 


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