JWT

A simple library to work with JSON Web Token and JSON Web Signature based on the RFC 7519.

Installation

Package is available on Packagist, you can install it using Composer.

composer require lcobucci/jwt

Dependencies

• PHP 5.5+ (v3.1) and PHP 7 (v4.x)
• OpenSSL Extension

Basic usage

Important: this is the documentation of our next major release (v4) and it WILL change. If you are using the stable version you should go to branch 3.1.

Creating

Just use the builder to create a new JWT/JWS tokens:

use Lcobucci\JWT\Configuration;

$config = new Configuration(); // This object helps to simplify the creation of the dependencies
                               // instead of using "?:" on constructors.

$token = $config->createBuilder()
                ->setIssuer('http://example.com') // Configures the issuer (iss claim)
                ->setAudience('http://example.org') // Configures the audience (aud claim)
                ->setId('4f1g23a12aa', true) // Configures the id (jti claim), replicating as a header item
                ->setIssuedAt(time()) // Configures the time that the token was issue (iat claim)
                ->setNotBefore(time() + 60) // Configures the time that the token can be used (nbf claim)
                ->setExpiration(time() + 3600) // Configures the expiration time of the token (exp claim)
                ->set('uid', 1) // Configures a new claim, called "uid"
                ->getToken(); // Retrieves the generated token


$token->getHeaders(); // Retrieves the token headers
$token->getClaims(); // Retrieves the token claims

echo $token->getHeader('jti'); // will print "4f1g23a12aa"
echo $token->getClaim('iss'); // will print "http://example.com"
echo $token->getClaim('uid'); // will print "1"
echo $token; // The string representation of the object is a JWT string (pretty easy, right?)

Parsing from strings

Use the parser to create a new token from a JWT string (using the previous token as example):

use Lcobucci\JWT\Configuration;

$config = new Configuration();
$token = $config->getParser()->parse((string) $token); // Parses from a string
$token->getHeaders(); // Retrieves the token header
$token->getClaims(); // Retrieves the token claims

echo $token->getHeader('jti'); // will print "4f1g23a12aa"
echo $token->getClaim('iss'); // will print "http://example.com"
echo $token->getClaim('uid'); // will print "1"

Validating

We can easily validate if the token is valid (using the previous token as example):

use Lcobucci\JWT\ValidationData;

$data = new ValidationData(); // It will use the current time to validate (iat, nbf and exp)
$data->setIssuer('http://example.com');
$data->setAudience('http://example.org');
$data->setId('4f1g23a12aa');

var_dump($token->validate($data)); // false, because token cannot be used before of now() + 60

$data->setCurrentTime(time() + 61); // changing the validation time to future

var_dump($token->validate($data)); // true, because current time is between "nbf" and "exp" claims

$data->setCurrentTime(time() + 4000); // changing the validation time to future

var_dump($token->validate($data)); // false, because token is expired since current time is greater than exp

Important

• You have to configure ValidationData informing all claims you want to validate the token.
• If ValidationData contains claims that are not being used in token or token has claims that are not configured in ValidationData they will be ignored by Token::validate().
• exp, nbf and iat claims are configured by default in ValidationData::__construct() with the current UNIX time (time()).

Token signature

We can use signatures to be able to verify if the token was not modified after its generation. This library implements Hmac, RSA and ECDSA signatures (using 256, 384 and 512).

Important

Do not allow the string sent to the Parser to dictate which signature algorithm to use, or else your application will be vulnerable to a critical JWT security vulnerability.

The examples below are safe because the choice in Signer is hard-coded and cannot be influenced by malicious users.

Hmac

Hmac signatures are really simple to be used:

use Lcobucci\JWT\Configuration;

$config = new Configuration();
$signer = $config->getSigner(); // Default signer is HMAC SHA256

$token = $config->createBuilder()
                ->setIssuer('http://example.com') // Configures the issuer (iss claim)
                ->setAudience('http://example.org') // Configures the audience (aud claim)
                ->setId('4f1g23a12aa', true) // Configures the id (jti claim), replicating as a header item
                ->setIssuedAt(time()) // Configures the time that the token was issue (iat claim)
                ->setNotBefore(time() + 60) // Configures the time that the token can be used (nbf claim)
                ->setExpiration(time() + 3600) // Configures the expiration time of the token (exp claim)
                ->set('uid', 1) // Configures a new claim, called "uid"
                ->sign($signer, 'testing') // creates a signature using "testing" as key
                ->getToken(); // Retrieves the generated token


var_dump($token->verify($signer, 'testing 1')); // false, because the key is different
var_dump($token->verify($signer, 'testing')); // true, because the key is the same

RSA and ECDSA

RSA and ECDSA signatures are based on public and private keys so you have to generate using the private key and verify using the public key:

use Lcobucci\JWT\Signer\Key;
use Lcobucci\JWT\Signer\Rsa\Sha256; // you can use Lcobucci\JWT\Signer\Ecdsa\Sha256 if you're using ECDSA keys

$config = new Configuration();
$config->setSigner(new Sha256()); // Change the signer to RSA SHA256

$signer = $config->getSigner();
$privateKey = new Key('file://{path to your private key}');

$token = $config->createBuilder()
                ->setIssuer('http://example.com') // Configures the issuer (iss claim)
                ->setAudience('http://example.org') // Configures the audience (aud claim)
                ->setId('4f1g23a12aa', true) // Configures the id (jti claim), replicating as a header item
                ->setIssuedAt(time()) // Configures the time that the token was issue (iat claim)
                ->setNotBefore(time() + 60) // Configures the time that the token can be used (nbf claim)
                ->setExpiration(time() + 3600) // Configures the expiration time of the token (exp claim)
                ->set('uid', 1) // Configures a new claim, called "uid"
                ->sign($signer,  $privateKey) // creates a signature using your private key
                ->getToken(); // Retrieves the generated token

$publicKey = new Key('file://{path to your public key}');

var_dump($token->verify($signer, $publicKey)); // true when the public key was generated by the private one =)

It's important to say that if you're using RSA keys you shouldn't invoke ECDSA signers (and vice-versa), otherwise sign() and verify() will raise an exception!

Security

Because of the awesome guys of Paragon Initiative and the PHP community's support we had a security audit for this library (thanks a lot guys)!

Check the result here!