jsonwebtoken

jsonwebtoken

An implementation of JSON Web Tokens.

This was developed against draft-ietf-oauth-json-web-token-08. It makes use of node-jws

Install

$ npm install jsonwebtoken

Usage

jwt.sign(payload, secretOrPrivateKey, options)

(Synchronous) Returns the JsonWebToken as string

payload could be an object literal, buffer or string. Please note that exp is only set if the payload is an object literal.

secretOrPrivateKey is a string or buffer containing either the secret for HMAC algorithms, or the PEM encoded private key for RSA and ECDSA.

options:

• algorithm (default: HS256)
• expiresInMinutes or expiresInSeconds
• audience
• subject
• issuer
• noTimestamp
• headers

If payload is not a buffer or a string, it will be coerced into a string using JSON.stringify.

If any expiresInMinutes, audience, subject, issuer are not provided, there is no default. The jwt generated won't include those properties in the payload.

Additional headers can be provided via the headers object.

Generated jwts will include an iat claim by default unless noTimestamp is specified.

Example

// sign with default (HMAC SHA256)
var jwt = require('jsonwebtoken');
var token = jwt.sign({ foo: 'bar' }, 'shhhhh');

// sign with RSA SHA256
var cert = fs.readFileSync('private.key');  // get private key
var token = jwt.sign({ foo: 'bar' }, cert, { algorithm: 'RS256'});

jwt.verify(token, secretOrPublicKey, [options, callback])

(Asynchronous) If a callback is supplied, function acts asynchronously. Callback passed the payload decoded if the signature (and optionally expiration, audience, issuer) are valid. If not, it will be passed the error.

(Synchronous) If a callback is not supplied, function acts synchronously. Returns the payload decoded if the signature (and optionally expiration, audience, issuer) are valid. If not, it will throw the error.

token is the JsonWebToken string

secretOrPublicKey is a string or buffer containing either the secret for HMAC algorithms, or the PEM encoded public key for RSA and ECDSA.

options

• algorithms: List of strings with the names of the allowed algorithms. For instance, ["HS256", "HS384"].
• audience: if you want to check audience (aud), provide a value here
• issuer: if you want to check issuer (iss), provide a value here
• ignoreExpiration: if true do not validate the expiration of the token.
• maxAge: optional sets an expiration based on the iat field. Eg 2h

// verify a token symmetric - synchronous
var decoded = jwt.verify(token, 'shhhhh');
console.log(decoded.foo) // bar

// verify a token symmetric
jwt.verify(token, 'shhhhh', function(err, decoded) {
  console.log(decoded.foo) // bar
});

// invalid token - synchronous
try {
  var decoded = jwt.verify(token, 'wrong-secret');
} catch(err) {
  // err
}

// invalid token
jwt.verify(token, 'wrong-secret', function(err, decoded) {
  // err
  // decoded undefined
});

// verify a token asymmetric
var cert = fs.readFileSync('public.pem');  // get public key
jwt.verify(token, cert, function(err, decoded) {
  console.log(decoded.foo) // bar
});

// verify audience
var cert = fs.readFileSync('public.pem');  // get public key
jwt.verify(token, cert, { audience: 'urn:foo' }, function(err, decoded) {
  // if audience mismatch, err == invalid audience
});

// verify issuer
var cert = fs.readFileSync('public.pem');  // get public key
jwt.verify(token, cert, { audience: 'urn:foo', issuer: 'urn:issuer' }, function(err, decoded) {
  // if issuer mismatch, err == invalid issuer
});

// alg mismatch
var cert = fs.readFileSync('public.pem'); // get public key
jwt.verify(token, cert, { algorithms: ['RS256'] }, function (err, payload) {
  // if token alg != RS256,  err == invalid signature
});

jwt.decode(token [, options])

(Synchronous) Returns the decoded payload without verifying if the signature is valid.

Warning: This will not verify whether the signature is valid. You should not use this for untrusted messages. You most likely want to use jwt.verify instead.

token is the JsonWebToken string

options:

• json: force JSON.parse on the payload even if the header doesn't contain "typ":"JWT".
• complete: return an object with the decoded payload and header.

Example

// get the decoded payload ignoring signature, no secretOrPrivateKey needed
var decoded = jwt.decode(token);

// get the decoded payload and header
var decoded = jwt.decode(token, {complete: true});
console.log(decoded.header);
console.log(decoded.payload)

Errors & Codes

Possible thrown errors during verification. Error is the first argument of the verification callback.

TokenExpiredError

Thrown error if the token is expired.

Error object:

• name: 'TokenExpiredError'
• message: 'jwt expired'
• expiredAt: [ExpDate]

jwt.verify(token, 'shhhhh', function(err, decoded) {
  if (err) {
    /*
      err = {
        name: 'TokenExpiredError',
        message: 'jwt expired',
        expiredAt: 1408621000
      }
    */
  }
});

JsonWebTokenError

Error object:

• name: 'JsonWebTokenError'
• message:
  • 'jwt malformed'
  • 'jwt signature is required'
  • 'invalid signature'
  • 'jwt audience invalid. expected: [OPTIONS AUDIENCE]'
  • 'jwt issuer invalid. expected: [OPTIONS ISSUER]'

jwt.verify(token, 'shhhhh', function(err, decoded) {
  if (err) {
    /*
      err = {
        name: 'JsonWebTokenError',
        message: 'jwt malformed'
      }
    */
  }
});

Algorithms supported

Array of supported algorithms. The following algorithms are currently supported.

alg Parameter Value	Digital Signature or MAC Algorithm
HS256	HMAC using SHA-256 hash algorithm
HS384	HMAC using SHA-384 hash algorithm
HS512	HMAC using SHA-512 hash algorithm
RS256	RSASSA using SHA-256 hash algorithm
RS384	RSASSA using SHA-384 hash algorithm
RS512	RSASSA using SHA-512 hash algorithm
ES256	ECDSA using P-256 curve and SHA-256 hash algorithm
ES384	ECDSA using P-384 curve and SHA-384 hash algorithm
ES512	ECDSA using P-521 curve and SHA-512 hash algorithm
none	No digital signature or MAC value included

Issue Reporting

If you have found a bug or if you have a feature request, please report them at this repository issues section. Please do not report security vulnerabilities on the public GitHub issue tracker. The Responsible Disclosure Program details the procedure for disclosing security issues.

TODO

• X.509 certificate chain is not checked

Author

Auth0

License

This project is licensed under the MIT license. See the LICENSE file for more info.