What is jsonwebtoken?
The jsonwebtoken npm package is used to implement JSON Web Tokens (JWT) in Node.js applications. JWTs are a compact, URL-safe means of representing claims to be transferred between two parties. The claims in a JWT are encoded as a JSON object that is used as the payload of a JSON Web Signature (JWS) structure or as the plaintext of a JSON Web Encryption (JWE) structure, enabling the claims to be digitally signed or integrity protected with a Message Authentication Code (MAC) and/or encrypted.
What are jsonwebtoken's main functionalities?
Token Signing
This feature allows you to create a digitally signed token. The token consists of a header, a payload, and a signature. The header typically consists of two parts: the type of the token, which is JWT, and the signing algorithm being used, such as HMAC SHA256 or RSA.
{"alg":"HS256","typ":"JWT"}.eyJsub":"1234567890","name":"John Doe","admin":true}.[signature]
Token Verification
This feature is used to verify the signature of an incoming JWT token to ensure that the sender is who they say they are and to ensure that the message wasn't changed along the way.
jwt.verify(token, 'secret', function(err, decoded) { console.log(decoded.foo) // bar })
Token Decoding
This feature allows you to decode a JWT without verifying it. This is useful for cases where you trust the token or have already verified it and just need to read the payload.
jwt.decode(token)
Other packages similar to jsonwebtoken
passport-jwt
A Passport strategy for authenticating with a JSON Web Token. This module lets you authenticate endpoints using a JWT. It is designed to be used with Passport.js. While jsonwebtoken is used for creating and verifying tokens, passport-jwt is used in the context of a web application to protect routes.
jose
JOSE is a comprehensive set of JWT, JWS, and JWE libraries. Compared to jsonwebtoken, it supports a wider range of algorithms and capabilities, including encryption. It is a more complex library that can be used for a broader set of use cases.
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 literal, buffer or string
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
audience
subject
issuer
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.
Example
var jwt = require('jsonwebtoken');
var token = jwt.sign({ foo: 'bar' }, 'shhhhh');
var cert = fs.readFileSync('private.key');
var token = jwt.sign({ foo: 'bar' }, cert, { algorithm: 'RS256'});
jwt.verify(token, secretOrPublicKey, options, callback)
(Synchronous with callback) Returns the payload decoded if the signature (and optionally expiration, audience, issuer) are valid. If not, it will return 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
audience
: if you want to check audience (aud
), provide a value hereissuer
: if you want to check issuer (iss
), provide a value here
jwt.verify(token, 'shhhhh', function(err, decoded) {
console.log(decoded.foo)
});
jwt.verify(token, 'wrong-secret', function(err, decoded) {
});
var cert = fs.readFileSync('public.pem');
jwt.verify(token, cert, function(err, decoded) {
console.log(decoded.foo)
});
var cert = fs.readFileSync('public.pem');
jwt.verify(token, cert, { audience: 'urn:foo' }, function(err, decoded) {
});
var cert = fs.readFileSync('public.pem');
jwt.verify(token, cert, { audience: 'urn:foo', issuer: 'urn:issuer' }, function(err, decoded) {
});
jwt.decode(token)
(Synchronous) Returns the decoded payload without verifying if the signature is valid.
token
is the JsonWebToken string
Example
var decoded = jwt.decode(token);
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) {
}
});
JsonWebTokenError
Error object:
- name: 'JsonWebTokenError'
- message:
- 'jwt malformed'
- 'jwt signature is required'
- 'invalid signature'
- 'jwt audience invalid. expected: [PAYLOAD AUDIENCE]'
- 'jwt issuer invalid. expected: [PAYLOAD ISSUER]'
jwt.verify(token, 'shhhhh', function(err, decoded) {
if (err) {
}
});
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
License
MIT