Installation

The recommended installation method is using Composer.

In your project root just run:

composer require league/oauth2-server

Ensure that you’ve set up your project to autoload Composer-installed packages.

Depending on which grant you are implementing you will need to implement a number of repository interfaces. Each grant documentation page lists which repositories are required, and each repository interface has it’s own documentation page.

The repositories are expected to return (on success) instances of entity interfaces; to make integration with your existing entities and models as easy as possible though, all required methods have been implemented as traits that you can use.

Generating public and private keys

The public/private key pair is used to sign and verify JWTs transmitted. The Authorization Server possesses the private key to sign tokens and the Resource Server possesses the corresponding public key to verify the signatures. To generate the private key run this command on the terminal:

openssl genrsa -out private.key 2048

If you want to provide a passphrase for your private key run this command instead:

openssl genrsa -aes128 -passout pass:_passphrase_ -out private.key 2048

then extract the public key from the private key:

openssl rsa -in private.key -pubout -out public.key

or use your passphrase if provided on private key generation:

openssl rsa -in private.key -passin pass:_passphrase_ -pubout -out public.key

The private key must be kept secret (i.e. out of the web-root of the authorization server). The authorization server also requires the public key.

If a passphrase has been used to generate private key it must be provided to the authorization server.

The public key should be distributed to any services (for example resource servers) that validate access tokens.

Generating encryption keys

Encryption keys are used to encrypt authorization and refresh codes. The AuthorizationServer accepts two kinds of encryption keys, a string password or a \Defuse\Crypto\Key object from the Secure PHP Encryption Library.

string password

A string password can vary in strength depending on the password chosen. To turn it into a strong encryption key the PBKDF2 key derivation function is used. This function derives an encryption key from a password and is slow by design. It uses a lot of CPU resources for a fraction of a second, applying key stretching to the password to reduce vulnerability to brute force attacks.

To generate a string password for the AuthorizationServer, you can run the following command in the terminal:

php -r 'echo base64_encode(random_bytes(32)), PHP_EOL;'

Key object

A \Defuse\Crypto\Key is a strong encryption key. This removes the need to use a slow key derivation function, reducing encryption and decryption times compared to using a string password.

A Key can be generated with the generate-defuse-key script. To generate a Key for the AuthorizationServer run the following command in the terminal:

vendor/bin/generate-defuse-key

The string can be loaded as a Key with Key::loadFromAsciiSafeString($string). For example:

  use \Defuse\Crypto\Key;
  $server = new AuthorizationServer(
      $clientRepository,
      $accessTokenRepository,
      $scopeRepository,
      $privateKeyPath,
      Key::loadFromAsciiSafeString($encryptionKey)
);