README

NOTICE: We're excited about the acquisition of Auth0 to bring you better support in PHP. This repo will be placed into security patch only mode and we will not be adding any further features. If you are looking for an API that is not supported in this library, please call the API directly. Our documentation for the supported Management APIs are located here: https://developer.okta.com/docs/reference/core-okta-api/. Please reach out to the DevForum for any questions.

Okta JWT Verifier for PHP

As a result of a successful authentication by obtaining an authorization grant from a user or using the Okta API, you will be provided with a signed JWT (id_token and/or access_token). A common use case for these access tokens is to use it inside of the Bearer authentication header to let your application know who the user is that is making the request. In order for you to know this use is valid, you will need to know how to validate the token against Okta. This guide gives you an example of how to do this using Okta's JWT Validation library for PHP.

This code does not work with the default authorization server. You must be using a custom authorization server. Please check if this is the case before using this code.

Release status

This library uses semantic versioning and follows Okta's library version policy.

The latest release can always be found on the releases page.

Installation

The Okta JWT Verifier can be installed through composer.

composer require okta/jwt-verifier

This library requires a JWT library. We currently support firebase/php-jwt version 5.2. You will have to install this or create your own adaptor.

composer require firebase/php-jwt ^5.2

To create your own adaptor, just implement the Okta/JwtVerifier/Adaptors/Adaptor in your own class.

You will also need to install a PSR-7 compliant library. We suggest that you use guzzlehttp/psr7 in your project.

composer require guzzlehttp/psr7

Setting up the Library

To validate a JWT, you will need a few different items:

1. Your issuer URL
2. The JWT string you want to verify
3. Access to your vendor autoload file in your script.

require_once("/vendor/autoload.php"); // This should be replaced with your path to your vendor/autoload.php file

$jwtVerifier = (new \Okta\JwtVerifier\JwtVerifierBuilder())
    ->setDiscovery(new \Okta\JwtVerifier\Discovery\Oauth) // This is not needed if using oauth.  The other option is `new \Okta\JwtVerifier\Discovery\OIDC`
    ->setAdaptor(new \Okta\JwtVerifier\Adaptors\FirebasePhpJwt)
    ->setAudience('api://default')
    ->setClientId('{clientId}')
    ->setIssuer('https://{yourOktaDomain}.com/oauth2/default')
    ->build();

Caching

It's strongly suggested to cache the keys to improve performance. You can pass an implementation of \Psr\SimpleCache\CacheInterface to the Adaptor constructor.

For example, in laravel:

// note: named parameters are only valid for php >= 8.0
->setAdaptor(new \Okta\JwtVerifier\Adaptors\FirebasePhpJwt(request: null, leeway: 120, cache: app('cache')->store()))

If using symphony, you may need to use an adaptor: https://symfony.com/doc/current/components/cache/psr6_psr16_adapters.html

Validating an Access Token

After you have a $jwtVerifier from the above section and an access_token from a successful sign in, or from a Bearer token in the authorization header, you will need to make sure that it is still valid. All you need to do is call the verifyAccessToken method (where $jwtString is your access token in string format).

$jwt = $jwtVerifier->verifyAccessToken($jwtString);

This will validate your JWT for the following:

• token expiration time
• the time it was issue at
• that the token issuer matches the expected value passed into the above helper
• that the token audience matches the expected value passed into the above helper

The result from the verify method is a Jwt object which has a few helper methods for you:

dump($jwt); //Returns instance of \Okta\JwtVerifier\JWT

dump($jwt->toJson()); // Returns Claims as JSON Object

dump($jwt->getClaims()); // Returns Claims as they come from the JWT Package used

dump($jwt->getIssuedAt()); // returns Carbon instance of issued at time
dump($jwt->getIssuedAt(false)); // returns timestamp of issued at time

dump($jwt->getExpirationTime()); //returns Carbon instance of Expiration Time
dump($jwt->getExpirationTime(false)); //returns timestamp of Expiration Time

Validating an Id Token

$jwt = $jwtVerifier->verifyIdToken($jwtString);

This will validate your JWT for the following:

• token expiration time
• the time it was issue at
• that the token issuer matches the expected value passed into the above helper
• that the token audience matches the expected value passed into the above helper

The result from the verify method is a Jwt object which has a few helper methods for you:

dump($jwt); //Returns instance of \Okta\JwtVerifier\JWT

dump($jwt->toJson()); // Returns Claims as JSON Object

dump($jwt->getClaims()); // Returns Claims as they come from the JWT Package used

dump($jwt->getIssuedAt()); // returns Carbon instance of issued at time
dump($jwt->getIssuedAt(false)); // returns timestamp of issued at time

dump($jwt->getExpirationTime()); //returns Carbon instance of Expiration Time
dump($jwt->getExpirationTime(false)); //returns timestamp of Expiration Time

Need help?

If you run into problems using the SDK, you can

• Ask questions on the Okta Developer Forums
• Post issues here on GitHub
• Working With OAuth 2.0 Tokens

Conclusion

The above are the basic steps for verifying an access token locally. The steps are not tied directly to a framework so you could plug in the okta/okta-jwt into the framework of your choice.