# jsonwebtoken [![Build Status](https://secure.travis-ci.org/auth0/node-jsonwebtoken.png)](http://travis-ci.org/auth0/node-jsonwebtoken)


An implementation of [JSON Web Tokens](https://tools.ietf.org/html/rfc7519).

This was developed against `draft-ietf-oauth-json-web-token-08`. It makes use of [node-jws](https://github.com/brianloveswords/node-jws)

# Install

```bash
$ npm install jsonwebtoken
```

# Usage

### jwt.sign(payload, secretOrPrivateKey, options, [callback])

(Asynchronous) If a callback is supplied, callback is called with the `err` or the JWT.

(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` or `alg` (default: `HS256`)
* `expiresIn`: expressed in seconds or a string describing a time span [rauchg/ms](https://github.com/rauchg/ms.js). Eg: `60`, `"2 days"`, `"10h"`, `"7d"`
* `notBefore`: expressed in seconds or a string describing a time span [rauchg/ms](https://github.com/rauchg/ms.js). Eg: `60`, `"2 days"`, `"10h"`, `"7d"`
* `audience`
* `issuer`
* `jwtid`
* `subject`
* `noTimestamp`
* `header`

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

There are no default values for `expiresIn`, `notBefore`, `audience`, `subject`, `issuer`. These claims can also be provided in the payload directly with `exp`, `nbf`, `aud` and `sub` respectively, but you can't include in both places.


The header can be customized via the `option.header` object.

Generated jwts will include an `iat` (issued at) claim by default unless `noTimestamp` is specified. If `iat` is inserted in the payload, it will be used instead of the real timestamp for calculating other things like `exp` given a timespan in `options.expiresIn`.

Example

```js
// sign with default (HMAC SHA256)
var jwt = require('jsonwebtoken');
var token = jwt.sign({ foo: 'bar' }, 'shhhhh');
//backdate a jwt 30 seconds
var older_token = jwt.sign({ foo: 'bar', iat: Math.floor(Date.now() / 1000) - 30 }, 'shhhhh'); 

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

// sign asynchronously
jwt.sign({ foo: 'bar' }, cert, { algorithm: 'RS256' }, function(err, token) {
  console.log(token);
});
```

### 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` (optional): string or array of strings of valid values for the `iss` field.
* `ignoreExpiration`: if `true` do not validate the expiration of the token.
* `ignoreNotBefore`...
* `subject`: if you want to check subject (`sub`), provide a value here
* `clockTolerance`: number of second to tolerate when checking the `nbf` and `exp` claims, to deal with small clock differences among different servers


```js
// 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
});

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

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

// 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

```js
// 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]

```js
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 id invalid. expected: [OPTIONS JWT ID]'
  * 'jwt subject invalid. expected: [OPTIONS SUBJECT]'

```js
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

# TODO

* X.509 certificate chain is not checked

## 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](https://auth0.com/whitehat) details the procedure for disclosing security issues.

## Author

[Auth0](auth0.com)

## License

This project is licensed under the MIT license. See the [LICENSE](LICENSE) file for more info.
