Update README.md

Updating readme to refer to the latest 5.1.* branch
Merge pull request #828 from Sephster/master
2025-05-31 14:12:07 +05:30 · 2017-12-23 13:20:52 +00:00 · 2017-12-23 02:14:34 +00:00 · 2017-12-23 02:06:18 +00:00 · 2017-12-23 01:52:33 +00:00 · 2017-12-13 21:05:36 +00:00
68 changed files with 2791 additions and 734 deletions
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,11 +7,10 @@ cache:
  - vendor

 php:
-  - 5.5.9
-  - 5.5
  - 5.6
  - 7.0
-  - hhvm
+  - 7.1
+  - 7.2

 install:
  - travis_retry composer install --no-interaction --prefer-source
@@ -21,4 +20,4 @@ script:

 branches:
  only:
-    - master
+    - master
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,62 @@
 # Changelog

+## 6.0.2 (released 2017-08-03)
+
+* An invalid refresh token that can't be decrypted now returns a HTTP 401 error instead of HTTP 400 (Issue #759)
+* Removed chmod from CryptKey and add toggle to disable checking (Issue #776)
+* Fixes invalid code challenge method payload key name (Issue #777)
+
+## 6.0.1 (released 2017-07-19)
+
+To address feedback from the security release the following change has been made:
+  
+* If an RSA key cannot be chmod'ed to 600 then it will now throw a E_USER_NOTICE instead of an exception.
+
+## 6.0.0 (released 2017-07-01)
+
+* Breaking change: The `AuthorizationServer` constructor now expects an encryption key string instead of a public key
+* Remove support for HHVM
+* Remove support for PHP 5.5
+
+## 5.1.4 (released 2017-07-01)
+
+* Fixed multiple security vulnerabilities as a result of a security audit paid for by the [Mozilla Secure Open Source Fund](https://wiki.mozilla.org/MOSS/Secure_Open_Source). All users of this library are encouraged to update as soon as possible to this version or version 6.0 or greater.
+	* It is recommended on each `AuthorizationServer` instance you set the `setEncryptionKey()`. This will result in stronger encryption being used. If this method is not set messages will be sent to the defined error handling routines (using `error_log`). Please see the examples and documentation for examples.
+* TravisCI now tests PHP 7.1 (Issue #671)
+* Fix middleware example fatal error (Issue #682)
+* Fix typo in the first README sentence (Issue #690)
+* Corrected DateInterval from 1 min to 1 month (Issue #709)
+
+## 5.1.3 (released 2016-10-12)
+
+* Fixed WWW-Authenticate header (Issue #669)
+* Increase the recommended RSA key length from 1024 to 2048 bits (Issue #668)
+
+## 5.1.2 (released 2016-09-19)
+
+* Fixed `finalizeScopes` call (Issue #650)
+
+## 5.1.1 (released 2016-07-26)
+
+* Improved test suite (Issue #614)
+* Updated docblocks (Issue #616)
+* Replace `array_shift` with `foreach` loop (Issue #621)
+* Allow easy addition of custom fields to Bearer token response (Issue #624)
+* Key file auto-generation from string (Issue #625)
+
+## 5.1.0 (released 2016-06-28)
+
+* Implemented RFC7636 (Issue #574)
+* Unify middleware exception responses (Issue #578)
+* Updated examples (Issue #589)
+* Ensure state is in access denied redirect (Issue #597)
+* Remove redundant `isExpired()` method from entity interfaces and traits (Issue #600)
+* Added a check for unique access token constraint violation (Issue #601)
+* Look at Authorization header directly for HTTP Basic auth checks (Issue #604)
+* Added catch Runtime exception when parsing JWT string (Issue #605)
+* Allow `paragonie/random_compat` 2.x (Issue #606)
+* Added `indigophp/hash-compat` to Composer suggestions and `require-dev` for PHP 5.5 support
+
 ## 5.0.3 (released 2016-05-04)

 * Fix hints in PasswordGrant (Issue #560)
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,7 +1,7 @@
 Thanks for contributing to this project.


-**Please submit your pull request against the `develop` branch only.**
+**Please submit your pull request against the `master` branch only.**


 Please ensure that you run `phpunit` from the project root after you've made any changes.
--- a/README.md
+++ b/README.md
@@ -1,5 +1,11 @@
 # PHP OAuth 2.0 Server

+### :warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning:
+### Security Notice 
+
+### Please upgrade to version `>=5.1.6` (backwards compatible) or `6.x` (one tiny breaking change) to fix some potential security vulnerabilities - [visit this page for more information](https://oauth2.thephpleague.com/v5-security-improvements/)
+### :warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning::warning:
+
 [![Latest Version](http://img.shields.io/packagist/v/league/oauth2-server.svg?style=flat-square)](https://github.com/thephpleague/oauth2-server/releases)
 [![Software License](https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat-square)](LICENSE.md)
 [![Build Status](https://img.shields.io/travis/thephpleague/oauth2-server/master.svg?style=flat-square)](https://travis-ci.org/thephpleague/oauth2-server)
@@ -7,7 +13,7 @@
 [![Quality Score](https://img.shields.io/scrutinizer/g/thephpleague/oauth2-server.svg?style=flat-square)](https://scrutinizer-ci.com/g/thephpleague/oauth2-server)
 [![Total Downloads](https://img.shields.io/packagist/dt/league/oauth2-server.svg?style=flat-square)](https://packagist.org/packages/league/oauth2-server)

-`league/oauth2-server` is a a standards compliant implementation of an [OAuth 2.0](https://tools.ietf.org/html/rfc6749) authorization server written in PHP which makes working with OAuth 2.0 trivial. You can easily configure an OAuth 2.0 server to protect your API with access tokens, or allow clients to request new access tokens and refresh them.
+`league/oauth2-server` is a standards compliant implementation of an [OAuth 2.0](https://tools.ietf.org/html/rfc6749) authorization server written in PHP which makes working with OAuth 2.0 trivial. You can easily configure an OAuth 2.0 server to protect your API with access tokens, or allow clients to request new access tokens and refresh them.

 It supports out of the box the following grants:

@@ -17,16 +23,23 @@ It supports out of the box the following grants:
 * Resource owner password credentials grant
 * Refresh grant

+The following RFCs are implemented:
+
+* [RFC6749 "OAuth 2.0"](https://tools.ietf.org/html/rfc6749)
+* [RFC6750 " The OAuth 2.0 Authorization Framework: Bearer Token Usage"](https://tools.ietf.org/html/rfc6750)
+* [RFC7519 "JSON Web Token (JWT)"](https://tools.ietf.org/html/rfc7519)
+* [RFC7636 "Proof Key for Code Exchange by OAuth Public Clients"](https://tools.ietf.org/html/rfc7636)
+
 This library was created by Alex Bilbie. Find him on Twitter at [@alexbilbie](https://twitter.com/alexbilbie).

 ## Requirements

 The following versions of PHP are supported:

-* PHP 5.5 (>=5.5.9)
 * PHP 5.6
 * PHP 7.0
-* HHVM
+* PHP 7.1
+* PHP 7.2

 The `openssl` extension is also required.

@@ -49,6 +62,14 @@ Bugs and feature request are tracked on [GitHub](https://github.com/thephpleague

 If you have any questions about OAuth _please_ open a ticket here; please **don't** email the address below.

+<a target='_blank' rel='nofollow' href='https://app.codesponsor.io/link/N2YMJcLBppt2Eg9E1jGu4gef/thephpleague/oauth2-server'>
+  <img alt='Sponsor' width='888' height='68' src='https://app.codesponsor.io/embed/N2YMJcLBppt2Eg9E1jGu4gef/thephpleague/oauth2-server.svg' />
+</a>
+
+## Commercial Support
+
+If you would like help implementing this library into your existing platform, or would be interested in OAuth advice or training for you and your team please get in touch with [Glynde Labs](https://glyndelabs.com).
+
 ## Security

 If you discover any security related issues, please email `hello@alexbilbie.com` instead of using the issue tracker.
@@ -59,8 +80,13 @@ This package is released under the MIT License. See the bundled [LICENSE](https:

 ## Credits

-This code is principally developed and maintained by [Alex Bilbie](https://twitter.com/alexbilbie).
+This code is principally developed and maintained by [Andy Millington](https://twitter.com/Sephster), [Brian 
+Retterer](https://twitter.com/bretterer), and [Simon Hamp](https://twitter.com/simonhamp).

-Special thanks to [all of these awesome contributors](https://github.com/thephpleague/oauth2-server/contributors)
+Between 2012 and 2017 this library was developed and maintained by [Alex Bilbie](https://alexbilbie.com/).
+
+Special thanks to [all of these awesome contributors](https://github.com/thephpleague/oauth2-server/contributors).
+
+Additional thanks go to the [Mozilla Secure Open Source Fund](https://wiki.mozilla.org/MOSS/Secure_Open_Source) for funding a security audit of this library.

 The initial code was developed as part of the [Linkey](http://linkey.blogs.lincoln.ac.uk) project which was funded by [JISC](http://jisc.ac.uk) under the Access and Identity Management programme.
--- a/composer.json
+++ b/composer.json
@@ -4,15 +4,16 @@
    "homepage": "https://oauth2.thephpleague.com/",
    "license": "MIT",
    "require": {
-        "php": ">=5.5.9",
+        "php": ">=5.6.0",
        "ext-openssl": "*",
        "league/event": "^2.1",
        "lcobucci/jwt": "^3.1",
-        "paragonie/random_compat": "^1.1",
-        "psr/http-message": "^1.0"
+        "paragonie/random_compat": "^2.0",
+        "psr/http-message": "^1.0",
+        "defuse/php-encryption": "^2.1"
    },
    "require-dev": {
-        "phpunit/phpunit": "^4.8 || ^5.0",
+        "phpunit/phpunit": "^4.8.38 || ^5.7.21",
        "zendframework/zend-diactoros": "^1.0"
    },
    "repositories": [
@@ -58,10 +59,5 @@
        "psr-4": {
            "LeagueTests\\": "tests/"
        }
-    },
-    "extra": {
-        "branch-alias": {
-            "dev-V5-WIP": "5.0-dev"
-        }
    }
 }
--- a/examples/README.md
+++ b/examples/README.md
@@ -3,7 +3,7 @@
 ## Installation

 0. Run `composer install` in this directory to install dependencies
-0. Create a private key `openssl genrsa -out private.key 1024`
+0. Create a private key `openssl genrsa -out private.key 2048`
 0. Create a public key `openssl rsa -in private.key -pubout > public.key`
 0. `cd` into the public directory
 0. Start a PHP server `php -S localhost:4444`
--- a/examples/composer.json
+++ b/examples/composer.json
@@ -5,8 +5,10 @@
    "require-dev": {
        "league/event": "^2.1",
        "lcobucci/jwt": "^3.1",
-        "paragonie/random_compat": "^1.1",
-        "psr/http-message": "^1.0"
+        "paragonie/random_compat": "^2.0",
+        "psr/http-message": "^1.0",
+        "defuse/php-encryption": "^2.1",
+        "zendframework/zend-diactoros": "^1.0"
    },
    "autoload": {
        "psr-4": {
--- a/examples/composer.lock
+++ b/examples/composer.lock
@@ -4,23 +4,25 @@
        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
        "This file is @generated automatically"
    ],
-    "hash": "48bcb7a3514d7c7f271c554ba1440124",
-    "content-hash": "e41be75973527cb9d63f27ad14ac8624",
+    "content-hash": "9813ed7c3b6dcf107f44df9392935b8f",
    "packages": [
        {
            "name": "container-interop/container-interop",
-            "version": "1.1.0",
+            "version": "1.2.0",
            "source": {
                "type": "git",
                "url": "https://github.com/container-interop/container-interop.git",
-                "reference": "fc08354828f8fd3245f77a66b9e23a6bca48297e"
+                "reference": "79cbf1341c22ec75643d841642dd5d6acd83bdb8"
            },
            "dist": {
                "type": "zip",
-                "url": "https://api.github.com/repos/container-interop/container-interop/zipball/fc08354828f8fd3245f77a66b9e23a6bca48297e",
-                "reference": "fc08354828f8fd3245f77a66b9e23a6bca48297e",
+                "url": "https://api.github.com/repos/container-interop/container-interop/zipball/79cbf1341c22ec75643d841642dd5d6acd83bdb8",
+                "reference": "79cbf1341c22ec75643d841642dd5d6acd83bdb8",
                "shasum": ""
            },
+            "require": {
+                "psr/container": "^1.0"
+            },
            "type": "library",
            "autoload": {
                "psr-4": {
@@ -32,7 +34,8 @@
                "MIT"
            ],
            "description": "Promoting the interoperability of container objects (DIC, SL, etc.)",
-            "time": "2014-12-30 15:22:37"
+            "homepage": "https://github.com/container-interop/container-interop",
+            "time": "2017-02-14T19:40:03+00:00"
        },
        {
            "name": "nikic/fast-route",
@@ -75,7 +78,7 @@
                "router",
                "routing"
            ],
-            "time": "2015-06-18 19:15:47"
+            "time": "2015-06-18T19:15:47+00:00"
        },
        {
            "name": "pimple/pimple",
@@ -121,20 +124,69 @@
                "container",
                "dependency injection"
            ],
-            "time": "2015-09-11 15:10:35"
+            "time": "2015-09-11T15:10:35+00:00"
        },
        {
-            "name": "psr/http-message",
-            "version": "1.0",
+            "name": "psr/container",
+            "version": "1.0.0",
            "source": {
                "type": "git",
-                "url": "https://github.com/php-fig/http-message.git",
-                "reference": "85d63699f0dbedb190bbd4b0d2b9dc707ea4c298"
+                "url": "https://github.com/php-fig/container.git",
+                "reference": "b7ce3b176482dbbc1245ebf52b181af44c2cf55f"
            },
            "dist": {
                "type": "zip",
-                "url": "https://api.github.com/repos/php-fig/http-message/zipball/85d63699f0dbedb190bbd4b0d2b9dc707ea4c298",
-                "reference": "85d63699f0dbedb190bbd4b0d2b9dc707ea4c298",
+                "url": "https://api.github.com/repos/php-fig/container/zipball/b7ce3b176482dbbc1245ebf52b181af44c2cf55f",
+                "reference": "b7ce3b176482dbbc1245ebf52b181af44c2cf55f",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Container\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "http://www.php-fig.org/"
+                }
+            ],
+            "description": "Common Container Interface (PHP FIG PSR-11)",
+            "homepage": "https://github.com/php-fig/container",
+            "keywords": [
+                "PSR-11",
+                "container",
+                "container-interface",
+                "container-interop",
+                "psr"
+            ],
+            "time": "2017-02-14T16:28:37+00:00"
+        },
+        {
+            "name": "psr/http-message",
+            "version": "1.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/http-message.git",
+                "reference": "f6561bf28d520154e4b0ec72be95418abe6d9363"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/http-message/zipball/f6561bf28d520154e4b0ec72be95418abe6d9363",
+                "reference": "f6561bf28d520154e4b0ec72be95418abe6d9363",
                "shasum": ""
            },
            "require": {
@@ -162,6 +214,7 @@
                }
            ],
            "description": "Common interface for HTTP messages",
+            "homepage": "https://github.com/php-fig/http-message",
            "keywords": [
                "http",
                "http-message",
@@ -170,7 +223,7 @@
                "request",
                "response"
            ],
-            "time": "2015-05-04 20:22:00"
+            "time": "2016-08-06T14:39:51+00:00"
        },
        {
            "name": "slim/slim",
@@ -236,22 +289,85 @@
                "micro",
                "router"
            ],
-            "time": "2015-12-07 14:11:09"
+            "time": "2015-12-07T14:11:09+00:00"
        }
    ],
    "packages-dev": [
        {
-            "name": "lcobucci/jwt",
-            "version": "3.1.1",
+            "name": "defuse/php-encryption",
+            "version": "v2.1.0",
            "source": {
                "type": "git",
-                "url": "https://github.com/lcobucci/jwt.git",
-                "reference": "afea8e682e911a21574fd8519321b32522fa25b5"
+                "url": "https://github.com/defuse/php-encryption.git",
+                "reference": "5176f5abb38d3ea8a6e3ac6cd3bbb54d8185a689"
            },
            "dist": {
                "type": "zip",
-                "url": "https://api.github.com/repos/lcobucci/jwt/zipball/afea8e682e911a21574fd8519321b32522fa25b5",
-                "reference": "afea8e682e911a21574fd8519321b32522fa25b5",
+                "url": "https://api.github.com/repos/defuse/php-encryption/zipball/5176f5abb38d3ea8a6e3ac6cd3bbb54d8185a689",
+                "reference": "5176f5abb38d3ea8a6e3ac6cd3bbb54d8185a689",
+                "shasum": ""
+            },
+            "require": {
+                "ext-openssl": "*",
+                "paragonie/random_compat": "~2.0",
+                "php": ">=5.4.0"
+            },
+            "require-dev": {
+                "nikic/php-parser": "^2.0|^3.0",
+                "phpunit/phpunit": "^4|^5"
+            },
+            "bin": [
+                "bin/generate-defuse-key"
+            ],
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Defuse\\Crypto\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Hornby",
+                    "email": "taylor@defuse.ca",
+                    "homepage": "https://defuse.ca/"
+                },
+                {
+                    "name": "Scott Arciszewski",
+                    "email": "info@paragonie.com",
+                    "homepage": "https://paragonie.com"
+                }
+            ],
+            "description": "Secure PHP Encryption Library",
+            "keywords": [
+                "aes",
+                "authenticated encryption",
+                "cipher",
+                "crypto",
+                "cryptography",
+                "encrypt",
+                "encryption",
+                "openssl",
+                "security",
+                "symmetric key cryptography"
+            ],
+            "time": "2017-05-18T21:28:48+00:00"
+        },
+        {
+            "name": "lcobucci/jwt",
+            "version": "3.2.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/lcobucci/jwt.git",
+                "reference": "ddce703826f9c5229781933b1a39069e38e6a0f3"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/lcobucci/jwt/zipball/ddce703826f9c5229781933b1a39069e38e6a0f3",
+                "reference": "ddce703826f9c5229781933b1a39069e38e6a0f3",
                "shasum": ""
            },
            "require": {
@@ -259,7 +375,7 @@
                "php": ">=5.5"
            },
            "require-dev": {
-                "mdanter/ecc": "~0.3",
+                "mdanter/ecc": "~0.3.1",
                "mikey179/vfsstream": "~1.5",
                "phpmd/phpmd": "~2.2",
                "phpunit/php-invoker": "~1.1",
@@ -296,7 +412,7 @@
                "JWS",
                "jwt"
            ],
-            "time": "2016-03-24 22:46:13"
+            "time": "2016-10-31T20:09:32+00:00"
        },
        {
            "name": "league/event",
@@ -346,20 +462,20 @@
                "event",
                "listener"
            ],
-            "time": "2015-05-21 12:24:47"
+            "time": "2015-05-21T12:24:47+00:00"
        },
        {
            "name": "paragonie/random_compat",
-            "version": "v1.4.1",
+            "version": "v2.0.10",
            "source": {
                "type": "git",
                "url": "https://github.com/paragonie/random_compat.git",
-                "reference": "c7e26a21ba357863de030f0b9e701c7d04593774"
+                "reference": "634bae8e911eefa89c1abfbf1b66da679ac8f54d"
            },
            "dist": {
                "type": "zip",
-                "url": "https://api.github.com/repos/paragonie/random_compat/zipball/c7e26a21ba357863de030f0b9e701c7d04593774",
-                "reference": "c7e26a21ba357863de030f0b9e701c7d04593774",
+                "url": "https://api.github.com/repos/paragonie/random_compat/zipball/634bae8e911eefa89c1abfbf1b66da679ac8f54d",
+                "reference": "634bae8e911eefa89c1abfbf1b66da679ac8f54d",
                "shasum": ""
            },
            "require": {
@@ -394,7 +510,7 @@
                "pseudorandom",
                "random"
            ],
-            "time": "2016-03-18 20:34:03"
+            "time": "2017-03-13T16:27:32+00:00"
        }
    ],
    "aliases": [],
--- a/examples/public/api.php
+++ b/examples/public/api.php
@@ -31,7 +31,6 @@ $app->add(
 $app->get(
    '/users',
    function (ServerRequestInterface $request, ResponseInterface $response) use ($app) {
-
        $users = [
            [
                'id'    => 123,
@@ -70,4 +69,4 @@ $app->get(
    }
 );

-$app->run();
+$app->run();
--- a/examples/public/auth_code.php
+++ b/examples/public/auth_code.php
@@ -36,7 +36,6 @@ $app = new App([
        $refreshTokenRepository = new RefreshTokenRepository();

        $privateKeyPath = 'file://' . __DIR__ . '/../private.key';
-        $publicKeyPath = 'file://' . __DIR__ . '/../public.key';

        // Setup the authorization server
        $server = new AuthorizationServer(
@@ -44,7 +43,7 @@ $app = new App([
            $accessTokenRepository,
            $scopeRepository,
            $privateKeyPath,
-            $publicKeyPath
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
        );

        // Enable the authentication code grant on the server with a token TTL of 1 hour
--- a/examples/public/client_credentials.php
+++ b/examples/public/client_credentials.php
@@ -30,9 +30,8 @@ $app = new App([
        $accessTokenRepository = new AccessTokenRepository(); // instance of AccessTokenRepositoryInterface

        // Path to public and private keys
-        $privateKey = 'file://'.__DIR__.'/../private.key';
+        $privateKey = 'file://' . __DIR__ . '/../private.key';
        //$privateKey = new CryptKey('file://path/to/private.key', 'passphrase'); // if private key has a pass phrase
-        $publicKey = 'file://'.__DIR__.'/../public.key';

        // Setup the authorization server
        $server = new AuthorizationServer(
@@ -40,7 +39,7 @@ $app = new App([
            $accessTokenRepository,
            $scopeRepository,
            $privateKey,
-            $publicKey
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
        );

        // Enable the client credentials grant on the server
--- a/examples/public/implicit.php
+++ b/examples/public/implicit.php
@@ -32,7 +32,6 @@ $app = new App([
        $accessTokenRepository = new AccessTokenRepository();

        $privateKeyPath = 'file://' . __DIR__ . '/../private.key';
-        $publicKeyPath = 'file://' . __DIR__ . '/../public.key';

        // Setup the authorization server
        $server = new AuthorizationServer(
@@ -40,8 +39,9 @@ $app = new App([
            $accessTokenRepository,
            $scopeRepository,
            $privateKeyPath,
-            $publicKeyPath
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
        );
+        $server->setEncryptionKey('lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen');

        // Enable the implicit grant on the server with a token TTL of 1 hour
        $server->enableGrantType(new ImplicitGrant(new \DateInterval('PT1H')));
--- a/examples/public/middleware_use.php
+++ b/examples/public/middleware_use.php
@@ -12,6 +12,7 @@ use League\OAuth2\Server\Grant\AuthCodeGrant;
 use League\OAuth2\Server\Grant\RefreshTokenGrant;
 use League\OAuth2\Server\Middleware\AuthorizationServerMiddleware;
 use League\OAuth2\Server\Middleware\ResourceServerMiddleware;
+use League\OAuth2\Server\ResourceServer;
 use OAuth2ServerExamples\Repositories\AccessTokenRepository;
 use OAuth2ServerExamples\Repositories\AuthCodeRepository;
 use OAuth2ServerExamples\Repositories\ClientRepository;
@@ -37,7 +38,6 @@ $app = new App([
        $refreshTokenRepository = new RefreshTokenRepository();

        $privateKeyPath = 'file://' . __DIR__ . '/../private.key';
-        $publicKeyPath = 'file://' . __DIR__ . '/../public.key';

        // Setup the authorization server
        $server = new AuthorizationServer(
@@ -45,7 +45,7 @@ $app = new App([
            $accessTokenRepository,
            $scopeRepository,
            $privateKeyPath,
-            $publicKeyPath
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
        );

        // Enable the authentication code grant on the server with a token TTL of 1 hour
@@ -61,7 +61,17 @@ $app = new App([
        // Enable the refresh token grant on the server with a token TTL of 1 month
        $server->enableGrantType(
            new RefreshTokenGrant($refreshTokenRepository),
-            new \DateInterval('PT1M')
+            new \DateInterval('P1M')
+        );
+
+        return $server;
+    },
+    ResourceServer::class => function () {
+        $publicKeyPath = 'file://' . __DIR__ . '/../public.key';
+
+        $server = new ResourceServer(
+            new AccessTokenRepository(),
+            $publicKeyPath
        );

        return $server;
@@ -94,6 +104,6 @@ $app->group('/api', function () {

        return $response->withBody($body);
    });
-})->add(new ResourceServerMiddleware($app->getContainer()->get(AuthorizationServer::class)));
+})->add(new ResourceServerMiddleware($app->getContainer()->get(ResourceServer::class)));

 $app->run();
--- a/examples/public/password.php
+++ b/examples/public/password.php
@@ -23,8 +23,8 @@ $app = new App([
            new ClientRepository(),                 // instance of ClientRepositoryInterface
            new AccessTokenRepository(),            // instance of AccessTokenRepositoryInterface
            new ScopeRepository(),                  // instance of ScopeRepositoryInterface
-            'file://'.__DIR__.'/../private.key',    // path to private key
-            'file://'.__DIR__.'/../public.key'      // path to public key
+            'file://' . __DIR__ . '/../private.key',    // path to private key
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'      // encryption key
        );

        $grant = new PasswordGrant(
@@ -54,19 +54,17 @@ $app->post(

            // Try to respond to the access token request
            return $server->respondToAccessTokenRequest($request, $response);
-
        } catch (OAuthServerException $exception) {

            // All instances of OAuthServerException can be converted to a PSR-7 response
            return $exception->generateHttpResponse($response);
-
        } catch (\Exception $exception) {

            // Catch unexpected exceptions
            $body = $response->getBody();
            $body->write($exception->getMessage());
-            return $response->withStatus(500)->withBody($body);

+            return $response->withStatus(500)->withBody($body);
        }
    }
 );
--- a/examples/public/refresh_token.php
+++ b/examples/public/refresh_token.php
@@ -17,7 +17,6 @@ use OAuth2ServerExamples\Repositories\ScopeRepository;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
 use Slim\App;
-use Zend\Diactoros\Stream;

 include __DIR__ . '/../vendor/autoload.php';

@@ -33,7 +32,6 @@ $app = new App([
        $refreshTokenRepository = new RefreshTokenRepository();

        $privateKeyPath = 'file://' . __DIR__ . '/../private.key';
-        $publicKeyPath = 'file://' . __DIR__ . '/../public.key';

        // Setup the authorization server
        $server = new AuthorizationServer(
@@ -41,7 +39,7 @@ $app = new App([
            $accessTokenRepository,
            $scopeRepository,
            $privateKeyPath,
-            $publicKeyPath
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
        );

        // Enable the refresh token grant on the server
@@ -66,10 +64,9 @@ $app->post('/access_token', function (ServerRequestInterface $request, ResponseI
    } catch (OAuthServerException $exception) {
        return $exception->generateHttpResponse($response);
    } catch (\Exception $exception) {
-        $body = new Stream('php://temp', 'r+');
-        $body->write($exception->getMessage());
+        $response->getBody()->write($exception->getMessage());

-        return $response->withStatus(500)->withBody($body);
+        return $response->withStatus(500);
    }
 });

--- a/examples/src/Repositories/ScopeRepository.php
+++ b/examples/src/Repositories/ScopeRepository.php
@@ -48,6 +48,13 @@ class ScopeRepository implements ScopeRepositoryInterface
        ClientEntityInterface $clientEntity,
        $userIdentifier = null
    ) {
+        // Example of programatically modifying the final scope of the access token
+        if ((int) $userIdentifier === 1) {
+            $scope = new ScopeEntity();
+            $scope->setIdentifier('email');
+            $scopes[] = $scope;
+        }
+
        return $scopes;
    }
 }
--- a/examples/src/Repositories/UserRepository.php
+++ b/examples/src/Repositories/UserRepository.php
@@ -11,7 +11,6 @@ namespace OAuth2ServerExamples\Repositories;

 use League\OAuth2\Server\Entities\ClientEntityInterface;
 use League\OAuth2\Server\Repositories\UserRepositoryInterface;
-use OAuth2ServerExamples\Entities\ScopeEntity;
 use OAuth2ServerExamples\Entities\UserEntity;

 class UserRepository implements UserRepositoryInterface
@@ -26,10 +25,6 @@ class UserRepository implements UserRepositoryInterface
        ClientEntityInterface $clientEntity
    ) {
        if ($username === 'alex' && $password === 'whisky') {
-            $scope = new ScopeEntity();
-            $scope->setIdentifier('email');
-            $scopes[] = $scope;
-
            return new UserEntity();
        }

--- a/src/AuthorizationServer.php
+++ b/src/AuthorizationServer.php
@@ -9,7 +9,6 @@

 namespace League\OAuth2\Server;

-use DateInterval;
 use League\Event\EmitterAwareInterface;
 use League\Event\EmitterAwareTrait;
 use League\OAuth2\Server\Exception\OAuthServerException;
@@ -28,7 +27,7 @@ class AuthorizationServer implements EmitterAwareInterface
    use EmitterAwareTrait;

    /**
-     * @var \League\OAuth2\Server\Grant\GrantTypeInterface[]
+     * @var GrantTypeInterface[]
     */
    protected $enabledGrantTypes = [];

@@ -38,88 +37,94 @@ class AuthorizationServer implements EmitterAwareInterface
    protected $grantTypeAccessTokenTTL = [];

    /**
-     * @var \League\OAuth2\Server\CryptKey
+     * @var CryptKey
     */
    protected $privateKey;

    /**
-     * @var \League\OAuth2\Server\CryptKey
+     * @var CryptKey
     */
    protected $publicKey;

    /**
-     * @var ResponseTypeInterface
+     * @var null|ResponseTypeInterface
     */
    protected $responseType;

    /**
-     * @var \League\OAuth2\Server\Repositories\ClientRepositoryInterface
+     * @var ClientRepositoryInterface
     */
    private $clientRepository;

    /**
-     * @var \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface
+     * @var AccessTokenRepositoryInterface
     */
    private $accessTokenRepository;

    /**
-     * @var \League\OAuth2\Server\Repositories\ScopeRepositoryInterface
+     * @var ScopeRepositoryInterface
     */
    private $scopeRepository;

+    /**
+     * @var string
+     */
+    private $encryptionKey;
+
+    /**
+     * @var string
+     */
+    private $defaultScope = '';
+
    /**
     * New server instance.
     *
-     * @param \League\OAuth2\Server\Repositories\ClientRepositoryInterface      $clientRepository
-     * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface $accessTokenRepository
-     * @param \League\OAuth2\Server\Repositories\ScopeRepositoryInterface       $scopeRepository
-     * @param \League\OAuth2\Server\CryptKey|string                             $privateKey
-     * @param \League\OAuth2\Server\CryptKey|string                             $publicKey
-     * @param null|\League\OAuth2\Server\ResponseTypes\ResponseTypeInterface    $responseType
+     * @param ClientRepositoryInterface      $clientRepository
+     * @param AccessTokenRepositoryInterface $accessTokenRepository
+     * @param ScopeRepositoryInterface       $scopeRepository
+     * @param CryptKey|string                $privateKey
+     * @param string                         $encryptionKey
+     * @param null|ResponseTypeInterface     $responseType
     */
    public function __construct(
        ClientRepositoryInterface $clientRepository,
        AccessTokenRepositoryInterface $accessTokenRepository,
        ScopeRepositoryInterface $scopeRepository,
        $privateKey,
-        $publicKey,
+        $encryptionKey,
        ResponseTypeInterface $responseType = null
    ) {
        $this->clientRepository = $clientRepository;
        $this->accessTokenRepository = $accessTokenRepository;
        $this->scopeRepository = $scopeRepository;

-        if (!$privateKey instanceof CryptKey) {
+        if ($privateKey instanceof CryptKey === false) {
            $privateKey = new CryptKey($privateKey);
        }
        $this->privateKey = $privateKey;
-
-        if (!$publicKey instanceof CryptKey) {
-            $publicKey = new CryptKey($publicKey);
-        }
-        $this->publicKey = $publicKey;
-
+        $this->encryptionKey = $encryptionKey;
        $this->responseType = $responseType;
    }

    /**
     * Enable a grant type on the server.
     *
-     * @param \League\OAuth2\Server\Grant\GrantTypeInterface $grantType
-     * @param \DateInterval                                  $accessTokenTTL
+     * @param GrantTypeInterface $grantType
+     * @param null|\DateInterval $accessTokenTTL
     */
-    public function enableGrantType(GrantTypeInterface $grantType, DateInterval $accessTokenTTL = null)
+    public function enableGrantType(GrantTypeInterface $grantType, \DateInterval $accessTokenTTL = null)
    {
-        if ($accessTokenTTL instanceof DateInterval === false) {
+        if ($accessTokenTTL instanceof \DateInterval === false) {
            $accessTokenTTL = new \DateInterval('PT1H');
        }

        $grantType->setAccessTokenRepository($this->accessTokenRepository);
        $grantType->setClientRepository($this->clientRepository);
        $grantType->setScopeRepository($this->scopeRepository);
+        $grantType->setDefaultScope($this->defaultScope);
        $grantType->setPrivateKey($this->privateKey);
-        $grantType->setPublicKey($this->publicKey);
        $grantType->setEmitter($this->getEmitter());
+        $grantType->setEncryptionKey($this->encryptionKey);

        $this->enabledGrantTypes[$grantType->getIdentifier()] = $grantType;
        $this->grantTypeAccessTokenTTL[$grantType->getIdentifier()] = $accessTokenTTL;
@@ -128,22 +133,17 @@ class AuthorizationServer implements EmitterAwareInterface
    /**
     * Validate an authorization request
     *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
     *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
     *
-     * @return \League\OAuth2\Server\RequestTypes\AuthorizationRequest|null
+     * @return AuthorizationRequest
     */
    public function validateAuthorizationRequest(ServerRequestInterface $request)
    {
-        $authRequest = null;
-        $enabledGrantTypes = $this->enabledGrantTypes;
-        while ($authRequest === null && $grantType = array_shift($enabledGrantTypes)) {
-            /** @var \League\OAuth2\Server\Grant\GrantTypeInterface $grantType */
+        foreach ($this->enabledGrantTypes as $grantType) {
            if ($grantType->canRespondToAuthorizationRequest($request)) {
-                $authRequest = $grantType->validateAuthorizationRequest($request);
-
-                return $authRequest;
+                return $grantType->validateAuthorizationRequest($request);
            }
        }

@@ -153,10 +153,10 @@ class AuthorizationServer implements EmitterAwareInterface
    /**
     * Complete an authorization request
     *
-     * @param \League\OAuth2\Server\RequestTypes\AuthorizationRequest $authRequest
-     * @param \Psr\Http\Message\ResponseInterface                     $response
+     * @param AuthorizationRequest $authRequest
+     * @param ResponseInterface    $response
     *
-     * @return \Psr\Http\Message\ResponseInterface
+     * @return ResponseInterface
     */
    public function completeAuthorizationRequest(AuthorizationRequest $authRequest, ResponseInterface $response)
    {
@@ -168,29 +168,29 @@ class AuthorizationServer implements EmitterAwareInterface
    /**
     * Return an access token response.
     *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param \Psr\Http\Message\ResponseInterface      $response
+     * @param ServerRequestInterface $request
+     * @param ResponseInterface      $response
     *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
     *
-     * @return \Psr\Http\Message\ResponseInterface
+     * @return ResponseInterface
     */
    public function respondToAccessTokenRequest(ServerRequestInterface $request, ResponseInterface $response)
    {
-        $tokenResponse = null;
-        while ($tokenResponse === null && $grantType = array_shift($this->enabledGrantTypes)) {
-            /** @var \League\OAuth2\Server\Grant\GrantTypeInterface $grantType */
-            if ($grantType->canRespondToAccessTokenRequest($request)) {
-                $tokenResponse = $grantType->respondToAccessTokenRequest(
-                    $request,
-                    $this->getResponseType(),
-                    $this->grantTypeAccessTokenTTL[$grantType->getIdentifier()]
-                );
+        foreach ($this->enabledGrantTypes as $grantType) {
+            if (!$grantType->canRespondToAccessTokenRequest($request)) {
+                continue;
            }
-        }
+            $tokenResponse = $grantType->respondToAccessTokenRequest(
+                $request,
+                $this->getResponseType(),
+                $this->grantTypeAccessTokenTTL[$grantType->getIdentifier()]
+            );

-        if ($tokenResponse instanceof ResponseTypeInterface) {
-            return $tokenResponse->generateHttpResponse($response);
+            if ($tokenResponse instanceof ResponseTypeInterface) {
+                return $tokenResponse->generateHttpResponse($response);
+            }
+            
        }

        throw OAuthServerException::unsupportedGrantType();
@@ -203,12 +203,23 @@ class AuthorizationServer implements EmitterAwareInterface
     */
    protected function getResponseType()
    {
-        if (!$this->responseType instanceof ResponseTypeInterface) {
+        if ($this->responseType instanceof ResponseTypeInterface === false) {
            $this->responseType = new BearerTokenResponse();
        }

        $this->responseType->setPrivateKey($this->privateKey);
+        $this->responseType->setEncryptionKey($this->encryptionKey);

        return $this->responseType;
    }
+
+    /**
+     * Set the default scope for the authorization server.
+     *
+     * @param string $defaultScope
+     */
+    public function setDefaultScope($defaultScope)
+    {
+        $this->defaultScope = $defaultScope;
+    }
 }
--- a/src/AuthorizationValidators/BearerTokenValidator.php
+++ b/src/AuthorizationValidators/BearerTokenValidator.php
@@ -12,6 +12,7 @@ namespace League\OAuth2\Server\AuthorizationValidators;
 use Lcobucci\JWT\Parser;
 use Lcobucci\JWT\Signer\Rsa\Sha256;
 use Lcobucci\JWT\ValidationData;
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\CryptTrait;
 use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
@@ -22,20 +23,33 @@ class BearerTokenValidator implements AuthorizationValidatorInterface
    use CryptTrait;

    /**
-     * @var \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface
+     * @var AccessTokenRepositoryInterface
     */
    private $accessTokenRepository;

    /**
-     * BearerTokenValidator constructor.
-     *
-     * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface $accessTokenRepository
+     * @var \League\OAuth2\Server\CryptKey
+     */
+    protected $publicKey;
+
+    /**
+     * @param AccessTokenRepositoryInterface $accessTokenRepository
     */
    public function __construct(AccessTokenRepositoryInterface $accessTokenRepository)
    {
        $this->accessTokenRepository = $accessTokenRepository;
    }

+    /**
+     * Set the public key
+     *
+     * @param \League\OAuth2\Server\CryptKey $key
+     */
+    public function setPublicKey(CryptKey $key)
+    {
+        $this->publicKey = $key;
+    }
+
    /**
     * {@inheritdoc}
     */
@@ -77,6 +91,9 @@ class BearerTokenValidator implements AuthorizationValidatorInterface
        } catch (\InvalidArgumentException $exception) {
            // JWT couldn't be parsed so return the request as is
            throw OAuthServerException::accessDenied($exception->getMessage());
+        } catch (\RuntimeException $exception) {
+            //JWR couldn't be parsed so return the request as is
+            throw OAuthServerException::accessDenied('Error while decoding to JSON');
        }
    }
 }
--- a/src/CryptKey.php
+++ b/src/CryptKey.php
@@ -8,26 +8,35 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server;

 class CryptKey
 {
+    const RSA_KEY_PATTERN =
+        '/^(-----BEGIN (RSA )?(PUBLIC|PRIVATE) KEY-----\n)(.|\n)+(-----END (RSA )?(PUBLIC|PRIVATE) KEY-----)$/';
+
    /**
     * @var string
     */
    protected $keyPath;

    /**
-     * @var string
+     * @var null|string
     */
    protected $passPhrase;

    /**
     * @param string      $keyPath
     * @param null|string $passPhrase
+     * @param bool        $keyPermissionsCheck
     */
-    public function __construct($keyPath, $passPhrase = null)
+    public function __construct($keyPath, $passPhrase = null, $keyPermissionsCheck = true)
    {
+        if (preg_match(self::RSA_KEY_PATTERN, $keyPath)) {
+            $keyPath = $this->saveKeyToFile($keyPath);
+        }
+
        if (strpos($keyPath, 'file://') !== 0) {
            $keyPath = 'file://' . $keyPath;
        }
@@ -36,10 +45,55 @@ class CryptKey
            throw new \LogicException(sprintf('Key path "%s" does not exist or is not readable', $keyPath));
        }

+        if ($keyPermissionsCheck === true) {
+            // Verify the permissions of the key
+            $keyPathPerms = decoct(fileperms($keyPath) & 0777);
+            if (in_array($keyPathPerms, ['600', '660'], true) === false) {
+                trigger_error(sprintf(
+                    'Key file "%s" permissions are not correct, should be 600 or 660 instead of %s',
+                    $keyPath,
+                    $keyPathPerms
+                ), E_USER_NOTICE);
+            }
+        }
+
        $this->keyPath = $keyPath;
        $this->passPhrase = $passPhrase;
    }

+    /**
+     * @param string $key
+     *
+     * @throws \RuntimeException
+     *
+     * @return string
+     */
+    private function saveKeyToFile($key)
+    {
+        $tmpDir = sys_get_temp_dir();
+        $keyPath = $tmpDir . '/' . sha1($key) . '.key';
+
+        if (!file_exists($keyPath) && !touch($keyPath)) {
+            // @codeCoverageIgnoreStart
+            throw new \RuntimeException(sprintf('"%s" key file could not be created', $keyPath));
+            // @codeCoverageIgnoreEnd
+        }
+
+        if (file_put_contents($keyPath, $key) === false) {
+            // @codeCoverageIgnoreStart
+            throw new \RuntimeException(sprintf('Unable to write key file to temporary directory "%s"', $tmpDir));
+            // @codeCoverageIgnoreEnd
+        }
+
+        if (chmod($keyPath, 0600) === false) {
+            // @codeCoverageIgnoreStart
+            throw new \RuntimeException(sprintf('The key file "%s" file mode could not be changed with chmod to 600', $keyPath));
+            // @codeCoverageIgnoreEnd
+        }
+
+        return 'file://' . $keyPath;
+    }
+
    /**
     * Retrieve key path.
     *
--- a/src/CryptTrait.php
+++ b/src/CryptTrait.php
@@ -8,73 +8,34 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server;

+use Defuse\Crypto\Crypto;
+
 trait CryptTrait
 {
    /**
-     * @var \League\OAuth2\Server\CryptKey
+     * @var string
     */
-    protected $privateKey;
-
-    /**
-     * @var \League\OAuth2\Server\CryptKey
-     */
-    protected $publicKey;
-
-    /**
-     * Set path to private key.
-     *
-     * @param \League\OAuth2\Server\CryptKey $privateKey
-     */
-    public function setPrivateKey(CryptKey $privateKey)
-    {
-        $this->privateKey = $privateKey;
-    }
-
-    /**
-     * Set path to public key.
-     *
-     * @param \League\OAuth2\Server\CryptKey $publicKey
-     */
-    public function setPublicKey(CryptKey $publicKey)
-    {
-        $this->publicKey = $publicKey;
-    }
+    protected $encryptionKey;

    /**
     * Encrypt data with a private key.
     *
     * @param string $unencryptedData
     *
+     * @throws \LogicException
+     *
     * @return string
     */
    protected function encrypt($unencryptedData)
    {
-        $privateKey = openssl_pkey_get_private($this->privateKey->getKeyPath(), $this->privateKey->getPassPhrase());
-        $privateKeyDetails = @openssl_pkey_get_details($privateKey);
-        if ($privateKeyDetails === null) {
-            throw new \LogicException(
-                sprintf('Could not get details of private key: %s', $this->privateKey->getKeyPath())
-            );
+        try {
+            return Crypto::encryptWithPassword($unencryptedData, $this->encryptionKey);
+        } catch (\Exception $e) {
+            throw new \LogicException($e->getMessage());
        }
-
-        $chunkSize = ceil($privateKeyDetails['bits'] / 8) - 11;
-        $output = '';
-
-        while ($unencryptedData) {
-            $chunk = substr($unencryptedData, 0, $chunkSize);
-            $unencryptedData = substr($unencryptedData, $chunkSize);
-            if (openssl_private_encrypt($chunk, $encrypted, $privateKey) === false) {
-                // @codeCoverageIgnoreStart
-                throw new \LogicException('Failed to encrypt data');
-                // @codeCoverageIgnoreEnd
-            }
-            $output .= $encrypted;
-        }
-        openssl_pkey_free($privateKey);
-
-        return base64_encode($output);
    }

    /**
@@ -88,31 +49,20 @@ trait CryptTrait
     */
    protected function decrypt($encryptedData)
    {
-        $publicKey = openssl_pkey_get_public($this->publicKey->getKeyPath());
-        $publicKeyDetails = @openssl_pkey_get_details($publicKey);
-        if ($publicKeyDetails === null) {
-            throw new \LogicException(
-                sprintf('Could not get details of public key: %s', $this->publicKey->getKeyPath())
-            );
+        try {
+            return Crypto::decryptWithPassword($encryptedData, $this->encryptionKey);
+        } catch (\Exception $e) {
+            throw new \LogicException($e->getMessage());
        }
+    }

-        $chunkSize = ceil($publicKeyDetails['bits'] / 8);
-        $output = '';
-
-        $encryptedData = base64_decode($encryptedData);
-
-        while ($encryptedData) {
-            $chunk = substr($encryptedData, 0, $chunkSize);
-            $encryptedData = substr($encryptedData, $chunkSize);
-            if (openssl_public_decrypt($chunk, $decrypted, $publicKey/*, OPENSSL_PKCS1_OAEP_PADDING*/) === false) {
-                // @codeCoverageIgnoreStart
-                throw new \LogicException('Failed to decrypt data');
-                // @codeCoverageIgnoreEnd
-            }
-            $output .= $decrypted;
-        }
-        openssl_pkey_free($publicKey);
-
-        return $output;
+    /**
+     * Set the encryption key
+     *
+     * @param string $key
+     */
+    public function setEncryptionKey($key = null)
+    {
+        $this->encryptionKey = $key;
    }
 }
--- a/src/Entities/AccessTokenEntityInterface.php
+++ b/src/Entities/AccessTokenEntityInterface.php
@@ -16,7 +16,7 @@ interface AccessTokenEntityInterface extends TokenInterface
    /**
     * Generate a JWT from the access token
     *
-     * @param \League\OAuth2\Server\CryptKey $privateKey
+     * @param CryptKey $privateKey
     *
     * @return string
     */
--- a/src/Entities/RefreshTokenEntityInterface.php
+++ b/src/Entities/RefreshTokenEntityInterface.php
@@ -42,21 +42,14 @@ interface RefreshTokenEntityInterface
    /**
     * Set the access token that the refresh token was associated with.
     *
-     * @param \League\OAuth2\Server\Entities\AccessTokenEntityInterface $accessToken
+     * @param AccessTokenEntityInterface $accessToken
     */
    public function setAccessToken(AccessTokenEntityInterface $accessToken);

    /**
     * Get the access token that the refresh token was originally associated with.
     *
-     * @return \League\OAuth2\Server\Entities\AccessTokenEntityInterface
+     * @return AccessTokenEntityInterface
     */
    public function getAccessToken();
-
-    /**
-     * Has the token expired?
-     *
-     * @return bool
-     */
-    public function isExpired();
 }
--- a/src/Entities/TokenInterface.php
+++ b/src/Entities/TokenInterface.php
@@ -63,14 +63,14 @@ interface TokenInterface
    /**
     * Set the client that the token was issued to.
     *
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $client
+     * @param ClientEntityInterface $client
     */
    public function setClient(ClientEntityInterface $client);

    /**
     * Associate a scope with the token.
     *
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface $scope
+     * @param ScopeEntityInterface $scope
     */
    public function addScope(ScopeEntityInterface $scope);

@@ -80,11 +80,4 @@ interface TokenInterface
     * @return ScopeEntityInterface[]
     */
    public function getScopes();
-
-    /**
-     * Has the token expired?
-     *
-     * @return bool
-     */
-    public function isExpired();
 }
--- a/src/Entities/Traits/AccessTokenTrait.php
+++ b/src/Entities/Traits/AccessTokenTrait.php
@@ -21,7 +21,7 @@ trait AccessTokenTrait
    /**
     * Generate a JWT from the access token
     *
-     * @param \League\OAuth2\Server\CryptKey $privateKey
+     * @param CryptKey $privateKey
     *
     * @return string
     */
--- a/src/Entities/Traits/ClientTrait.php
+++ b/src/Entities/Traits/ClientTrait.php
@@ -11,8 +11,14 @@ namespace League\OAuth2\Server\Entities\Traits;

 trait ClientTrait
 {
+    /**
+     * @var string
+     */
    protected $name;

+    /**
+     * @var string|string[]
+     */
    protected $redirectUri;

    /**
--- a/src/Entities/Traits/RefreshTokenTrait.php
+++ b/src/Entities/Traits/RefreshTokenTrait.php
@@ -9,7 +9,6 @@

 namespace League\OAuth2\Server\Entities\Traits;

-use DateTime;
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;

 trait RefreshTokenTrait
@@ -20,7 +19,7 @@ trait RefreshTokenTrait
    protected $accessToken;

    /**
-     * @var DateTime
+     * @var \DateTime
     */
    protected $expiryDateTime;

@@ -43,7 +42,7 @@ trait RefreshTokenTrait
    /**
     * Get the token's expiry date time.
     *
-     * @return DateTime
+     * @return \DateTime
     */
    public function getExpiryDateTime()
    {
@@ -53,20 +52,10 @@ trait RefreshTokenTrait
    /**
     * Set the date time when the token expires.
     *
-     * @param DateTime $dateTime
+     * @param \DateTime $dateTime
     */
-    public function setExpiryDateTime(DateTime $dateTime)
+    public function setExpiryDateTime(\DateTime $dateTime)
    {
        $this->expiryDateTime = $dateTime;
    }
-
-    /**
-     * Has the token expired?
-     *
-     * @return bool
-     */
-    public function isExpired()
-    {
-        return (new DateTime()) > $this->getExpiryDateTime();
-    }
 }
--- a/src/Entities/Traits/TokenEntityTrait.php
+++ b/src/Entities/Traits/TokenEntityTrait.php
@@ -9,7 +9,6 @@

 namespace League\OAuth2\Server\Entities\Traits;

-use DateTime;
 use League\OAuth2\Server\Entities\ClientEntityInterface;
 use League\OAuth2\Server\Entities\ScopeEntityInterface;

@@ -21,7 +20,7 @@ trait TokenEntityTrait
    protected $scopes = [];

    /**
-     * @var DateTime
+     * @var \DateTime
     */
    protected $expiryDateTime;

@@ -38,7 +37,7 @@ trait TokenEntityTrait
    /**
     * Associate a scope with the token.
     *
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface $scope
+     * @param ScopeEntityInterface $scope
     */
    public function addScope(ScopeEntityInterface $scope)
    {
@@ -58,7 +57,7 @@ trait TokenEntityTrait
    /**
     * Get the token's expiry date time.
     *
-     * @return DateTime
+     * @return \DateTime
     */
    public function getExpiryDateTime()
    {
@@ -68,9 +67,9 @@ trait TokenEntityTrait
    /**
     * Set the date time when the token expires.
     *
-     * @param DateTime $dateTime
+     * @param \DateTime $dateTime
     */
-    public function setExpiryDateTime(DateTime $dateTime)
+    public function setExpiryDateTime(\DateTime $dateTime)
    {
        $this->expiryDateTime = $dateTime;
    }
@@ -108,20 +107,10 @@ trait TokenEntityTrait
    /**
     * Set the client that the token was issued to.
     *
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $client
+     * @param ClientEntityInterface $client
     */
    public function setClient(ClientEntityInterface $client)
    {
        $this->client = $client;
    }
-
-    /**
-     * Has the token expired?
-     *
-     * @return bool
-     */
-    public function isExpired()
-    {
-        return (new DateTime()) > $this->getExpiryDateTime();
-    }
 }
--- a/src/Exception/OAuthServerException.php
+++ b/src/Exception/OAuthServerException.php
@@ -69,7 +69,7 @@ class OAuthServerException extends \Exception
     * Invalid request error.
     *
     * @param string      $parameter The invalid parameter
-     * @param string|null $hint
+     * @param null|string $hint
     *
     * @return static
     */
@@ -105,7 +105,15 @@ class OAuthServerException extends \Exception
    public static function invalidScope($scope, $redirectUri = null)
    {
        $errorMessage = 'The requested scope is invalid, unknown, or malformed';
-        $hint = sprintf('Check the `%s` scope', $scope);
+
+        if (empty($scope)) {
+            $hint = 'Specify a scope in the request or set a default scope';
+        } else {
+            $hint = sprintf(
+                'Check the `%s` scope',
+                htmlspecialchars($scope, ENT_QUOTES, 'UTF-8', false)
+            );
+        }

        return new static($errorMessage, 5, 'invalid_scope', 400, $hint, $redirectUri);
    }
@@ -143,20 +151,20 @@ class OAuthServerException extends \Exception
    /**
     * Invalid refresh token.
     *
-     * @param string|null $hint
+     * @param null|string $hint
     *
     * @return static
     */
    public static function invalidRefreshToken($hint = null)
    {
-        return new static('The refresh token is invalid.', 8, 'invalid_request', 400, $hint);
+        return new static('The refresh token is invalid.', 8, 'invalid_request', 401, $hint);
    }

    /**
     * Access denied.
     *
-     * @param string|null $hint
-     * @param string|null $redirectUri
+     * @param null|string $hint
+     * @param null|string $redirectUri
     *
     * @return static
     */
@@ -172,6 +180,26 @@ class OAuthServerException extends \Exception
        );
    }

+    /**
+     * Invalid grant.
+     *
+     * @param string $hint
+     *
+     * @return static
+     */
+    public static function invalidGrant($hint = '')
+    {
+        return new static(
+            'The provided authorization grant (e.g., authorization code, resource owner credentials) or refresh token '
+                . 'is invalid, expired, revoked, does not match the redirection URI used in the authorization request, '
+                . 'or was issued to another client.',
+            10,
+            'invalid_grant',
+            400,
+            $hint
+        );
+    }
+
    /**
     * @return string
     */
@@ -183,11 +211,10 @@ class OAuthServerException extends \Exception
    /**
     * Generate a HTTP response.
     *
-     * @param \Psr\Http\Message\ResponseInterface $response
-     * @param bool                                $useFragment True if errors should be in the URI fragment instead of
-     *                                                         query string
+     * @param ResponseInterface $response
+     * @param bool              $useFragment True if errors should be in the URI fragment instead of query string
     *
-     * @return \Psr\Http\Message\ResponseInterface
+     * @return ResponseInterface
     */
    public function generateHttpResponse(ResponseInterface $response, $useFragment = false)
    {
@@ -248,7 +275,7 @@ class OAuthServerException extends \Exception
            ) {
                $authScheme = 'Bearer';
            }
-            $headers[] = 'WWW-Authenticate: ' . $authScheme . ' realm="OAuth"';
+            $headers['WWW-Authenticate'] = $authScheme . ' realm="OAuth"';
        }
        // @codeCoverageIgnoreEnd
        return $headers;
--- a/src/Exception/UniqueTokenIdentifierConstraintViolationException.php
+++ b/src/Exception/UniqueTokenIdentifierConstraintViolationException.php
@@ -0,0 +1,20 @@
+<?php
+/**
+ * @author      Ivan Kurnosov <zerkms@zerkms.com>
+ * @copyright   Copyright (c) Alex Bilbie
+ * @license     http://mit-license.org/
+ *
+ * @link        https://github.com/thephpleague/oauth2-server
+ */
+
+namespace League\OAuth2\Server\Exception;
+
+class UniqueTokenIdentifierConstraintViolationException extends OAuthServerException
+{
+    public static function create()
+    {
+        $errorMessage = 'Could not create unique access token identifier';
+
+        return new static($errorMessage, 100, 'access_token_duplicate', 500);
+    }
+}
--- a/src/Grant/AbstractGrant.php
+++ b/src/Grant/AbstractGrant.php
@@ -11,11 +11,15 @@
 namespace League\OAuth2\Server\Grant;

 use League\Event\EmitterAwareTrait;
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\CryptTrait;
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
+use League\OAuth2\Server\Entities\AuthCodeEntityInterface;
 use League\OAuth2\Server\Entities\ClientEntityInterface;
+use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
 use League\OAuth2\Server\Entities\ScopeEntityInterface;
 use League\OAuth2\Server\Exception\OAuthServerException;
+use League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\Repositories\AuthCodeRepositoryInterface;
 use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
@@ -35,6 +39,8 @@ abstract class AbstractGrant implements GrantTypeInterface

    const SCOPE_DELIMITER_STRING = ' ';

+    const MAX_RANDOM_TOKEN_GENERATION_ATTEMPTS = 10;
+
    /**
     * @var ClientRepositoryInterface
     */
@@ -51,17 +57,17 @@ abstract class AbstractGrant implements GrantTypeInterface
    protected $scopeRepository;

    /**
-     * @var \League\OAuth2\Server\Repositories\AuthCodeRepositoryInterface
+     * @var AuthCodeRepositoryInterface
     */
    protected $authCodeRepository;

    /**
-     * @var \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface
+     * @var RefreshTokenRepositoryInterface
     */
    protected $refreshTokenRepository;

    /**
-     * @var \League\OAuth2\Server\Repositories\UserRepositoryInterface
+     * @var UserRepositoryInterface
     */
    protected $userRepository;

@@ -70,6 +76,16 @@ abstract class AbstractGrant implements GrantTypeInterface
     */
    protected $refreshTokenTTL;

+    /**
+     * @var \League\OAuth2\Server\CryptKey
+     */
+    protected $privateKey;
+
+    /**
+     * @string
+     */
+    protected $defaultScope;
+
    /**
     * @param ClientRepositoryInterface $clientRepository
     */
@@ -95,7 +111,7 @@ abstract class AbstractGrant implements GrantTypeInterface
    }

    /**
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
     */
    public function setRefreshTokenRepository(RefreshTokenRepositoryInterface $refreshTokenRepository)
    {
@@ -103,7 +119,7 @@ abstract class AbstractGrant implements GrantTypeInterface
    }

    /**
-     * @param \League\OAuth2\Server\Repositories\AuthCodeRepositoryInterface $authCodeRepository
+     * @param AuthCodeRepositoryInterface $authCodeRepository
     */
    public function setAuthCodeRepository(AuthCodeRepositoryInterface $authCodeRepository)
    {
@@ -111,7 +127,7 @@ abstract class AbstractGrant implements GrantTypeInterface
    }

    /**
-     * @param \League\OAuth2\Server\Repositories\UserRepositoryInterface $userRepository
+     * @param UserRepositoryInterface $userRepository
     */
    public function setUserRepository(UserRepositoryInterface $userRepository)
    {
@@ -126,32 +142,44 @@ abstract class AbstractGrant implements GrantTypeInterface
        $this->refreshTokenTTL = $refreshTokenTTL;
    }

+    /**
+     * Set the private key
+     *
+     * @param \League\OAuth2\Server\CryptKey $key
+     */
+    public function setPrivateKey(CryptKey $key)
+    {
+        $this->privateKey = $key;
+    }
+
+    /**
+     * @param string $scope
+     */
+    public function setDefaultScope($scope)
+    {
+        $this->defaultScope = $scope;
+    }
+
    /**
     * Validate the client.
     *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
     *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
     *
-     * @return \League\OAuth2\Server\Entities\ClientEntityInterface
+     * @return ClientEntityInterface
     */
    protected function validateClient(ServerRequestInterface $request)
    {
-        $clientId = $this->getRequestParameter(
-            'client_id',
-            $request,
-            $this->getServerParameter('PHP_AUTH_USER', $request)
-        );
+        list($basicAuthUser, $basicAuthPassword) = $this->getBasicAuthCredentials($request);
+
+        $clientId = $this->getRequestParameter('client_id', $request, $basicAuthUser);
        if (is_null($clientId)) {
            throw OAuthServerException::invalidRequest('client_id');
        }

        // If the client is confidential require the client secret
-        $clientSecret = $this->getRequestParameter(
-            'client_secret',
-            $request,
-            $this->getServerParameter('PHP_AUTH_PW', $request)
-        );
+        $clientSecret = $this->getRequestParameter('client_secret', $request, $basicAuthPassword);

        $client = $this->clientRepository->getClientEntity(
            $clientId,
@@ -160,7 +188,7 @@ abstract class AbstractGrant implements GrantTypeInterface
            true
        );

-        if (!$client instanceof ClientEntityInterface) {
+        if ($client instanceof ClientEntityInterface === false) {
            $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
            throw OAuthServerException::invalidClient();
        }
@@ -192,41 +220,41 @@ abstract class AbstractGrant implements GrantTypeInterface
     * @param string $scopes
     * @param string $redirectUri
     *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
     *
-     * @return \League\OAuth2\Server\Entities\ScopeEntityInterface[]
+     * @return ScopeEntityInterface[]
     */
-    public function validateScopes(
-        $scopes,
-        $redirectUri = null
-    ) {
-        $scopesList = array_filter(
-            explode(self::SCOPE_DELIMITER_STRING, trim($scopes)),
-            function ($scope) {
-                return !empty($scope);
-            }
-        );
+    public function validateScopes($scopes, $redirectUri = null)
+    {
+        $scopesList = array_filter(explode(self::SCOPE_DELIMITER_STRING, trim($scopes)), function ($scope) {
+            return !empty($scope);
+        });
+
+        $validScopes = [];

-        $scopes = [];
        foreach ($scopesList as $scopeItem) {
            $scope = $this->scopeRepository->getScopeEntityByIdentifier($scopeItem);

-            if (!$scope instanceof ScopeEntityInterface) {
+            if ($scope instanceof ScopeEntityInterface === false) {
                throw OAuthServerException::invalidScope($scopeItem, $redirectUri);
            }

-            $scopes[] = $scope;
+            $validScopes[] = $scope;
        }

-        return $scopes;
+        if (empty($validScopes)) {
+            throw OAuthServerException::invalidScope('', $redirectUri);
+        }
+
+        return $validScopes;
    }

    /**
     * Retrieve request parameter.
     *
-     * @param string                                   $parameter
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param mixed                                    $default
+     * @param string                 $parameter
+     * @param ServerRequestInterface $request
+     * @param mixed                  $default
     *
     * @return null|string
     */
@@ -237,12 +265,45 @@ abstract class AbstractGrant implements GrantTypeInterface
        return isset($requestParameters[$parameter]) ? $requestParameters[$parameter] : $default;
    }

+    /**
+     * Retrieve HTTP Basic Auth credentials with the Authorization header
+     * of a request. First index of the returned array is the username,
+     * second is the password (so list() will work). If the header does
+     * not exist, or is otherwise an invalid HTTP Basic header, return
+     * [null, null].
+     *
+     * @param ServerRequestInterface $request
+     *
+     * @return string[]|null[]
+     */
+    protected function getBasicAuthCredentials(ServerRequestInterface $request)
+    {
+        if (!$request->hasHeader('Authorization')) {
+            return [null, null];
+        }
+
+        $header = $request->getHeader('Authorization')[0];
+        if (strpos($header, 'Basic ') !== 0) {
+            return [null, null];
+        }
+
+        if (!($decoded = base64_decode(substr($header, 6)))) {
+            return [null, null];
+        }
+
+        if (strpos($decoded, ':') === false) {
+            return [null, null]; // HTTP Basic header without colon isn't valid
+        }
+
+        return explode(':', $decoded, 2);
+    }
+
    /**
     * Retrieve query string parameter.
     *
-     * @param string                                   $parameter
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param mixed                                    $default
+     * @param string                 $parameter
+     * @param ServerRequestInterface $request
+     * @param mixed                  $default
     *
     * @return null|string
     */
@@ -254,9 +315,9 @@ abstract class AbstractGrant implements GrantTypeInterface
    /**
     * Retrieve cookie parameter.
     *
-     * @param string                                   $parameter
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param mixed                                    $default
+     * @param string                 $parameter
+     * @param ServerRequestInterface $request
+     * @param mixed                  $default
     *
     * @return null|string
     */
@@ -268,9 +329,9 @@ abstract class AbstractGrant implements GrantTypeInterface
    /**
     * Retrieve server parameter.
     *
-     * @param string                                   $parameter
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param mixed                                    $default
+     * @param string                 $parameter
+     * @param ServerRequestInterface $request
+     * @param mixed                  $default
     *
     * @return null|string
     */
@@ -282,12 +343,15 @@ abstract class AbstractGrant implements GrantTypeInterface
    /**
     * Issue an access token.
     *
-     * @param \DateInterval                                         $accessTokenTTL
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface  $client
-     * @param string                                                $userIdentifier
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface[] $scopes
+     * @param \DateInterval          $accessTokenTTL
+     * @param ClientEntityInterface  $client
+     * @param string                 $userIdentifier
+     * @param ScopeEntityInterface[] $scopes
     *
-     * @return \League\OAuth2\Server\Entities\AccessTokenEntityInterface
+     * @throws OAuthServerException
+     * @throws UniqueTokenIdentifierConstraintViolationException
+     *
+     * @return AccessTokenEntityInterface
     */
    protected function issueAccessToken(
        \DateInterval $accessTokenTTL,
@@ -295,31 +359,44 @@ abstract class AbstractGrant implements GrantTypeInterface
        $userIdentifier,
        array $scopes = []
    ) {
+        $maxGenerationAttempts = self::MAX_RANDOM_TOKEN_GENERATION_ATTEMPTS;
+
        $accessToken = $this->accessTokenRepository->getNewToken($client, $scopes, $userIdentifier);
        $accessToken->setClient($client);
        $accessToken->setUserIdentifier($userIdentifier);
-        $accessToken->setIdentifier($this->generateUniqueIdentifier());
        $accessToken->setExpiryDateTime((new \DateTime())->add($accessTokenTTL));

        foreach ($scopes as $scope) {
            $accessToken->addScope($scope);
        }

-        $this->accessTokenRepository->persistNewAccessToken($accessToken);
+        while ($maxGenerationAttempts-- > 0) {
+            $accessToken->setIdentifier($this->generateUniqueIdentifier());
+            try {
+                $this->accessTokenRepository->persistNewAccessToken($accessToken);

-        return $accessToken;
+                return $accessToken;
+            } catch (UniqueTokenIdentifierConstraintViolationException $e) {
+                if ($maxGenerationAttempts === 0) {
+                    throw $e;
+                }
+            }
+        }
    }

    /**
     * Issue an auth code.
     *
-     * @param \DateInterval                                         $authCodeTTL
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface  $client
-     * @param string                                                $userIdentifier
-     * @param string                                                $redirectUri
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface[] $scopes
+     * @param \DateInterval          $authCodeTTL
+     * @param ClientEntityInterface  $client
+     * @param string                 $userIdentifier
+     * @param string                 $redirectUri
+     * @param ScopeEntityInterface[] $scopes
     *
-     * @return \League\OAuth2\Server\Entities\AuthCodeEntityInterface
+     * @throws OAuthServerException
+     * @throws UniqueTokenIdentifierConstraintViolationException
+     *
+     * @return AuthCodeEntityInterface
     */
    protected function issueAuthCode(
        \DateInterval $authCodeTTL,
@@ -328,8 +405,9 @@ abstract class AbstractGrant implements GrantTypeInterface
        $redirectUri,
        array $scopes = []
    ) {
+        $maxGenerationAttempts = self::MAX_RANDOM_TOKEN_GENERATION_ATTEMPTS;
+
        $authCode = $this->authCodeRepository->getNewAuthCode();
-        $authCode->setIdentifier($this->generateUniqueIdentifier());
        $authCode->setExpiryDateTime((new \DateTime())->add($authCodeTTL));
        $authCode->setClient($client);
        $authCode->setUserIdentifier($userIdentifier);
@@ -339,26 +417,48 @@ abstract class AbstractGrant implements GrantTypeInterface
            $authCode->addScope($scope);
        }

-        $this->authCodeRepository->persistNewAuthCode($authCode);
+        while ($maxGenerationAttempts-- > 0) {
+            $authCode->setIdentifier($this->generateUniqueIdentifier());
+            try {
+                $this->authCodeRepository->persistNewAuthCode($authCode);

-        return $authCode;
+                return $authCode;
+            } catch (UniqueTokenIdentifierConstraintViolationException $e) {
+                if ($maxGenerationAttempts === 0) {
+                    throw $e;
+                }
+            }
+        }
    }

    /**
-     * @param \League\OAuth2\Server\Entities\AccessTokenEntityInterface $accessToken
+     * @param AccessTokenEntityInterface $accessToken
     *
-     * @return \League\OAuth2\Server\Entities\RefreshTokenEntityInterface
+     * @throws OAuthServerException
+     * @throws UniqueTokenIdentifierConstraintViolationException
+     *
+     * @return RefreshTokenEntityInterface
     */
    protected function issueRefreshToken(AccessTokenEntityInterface $accessToken)
    {
+        $maxGenerationAttempts = self::MAX_RANDOM_TOKEN_GENERATION_ATTEMPTS;
+
        $refreshToken = $this->refreshTokenRepository->getNewRefreshToken();
-        $refreshToken->setIdentifier($this->generateUniqueIdentifier());
        $refreshToken->setExpiryDateTime((new \DateTime())->add($this->refreshTokenTTL));
        $refreshToken->setAccessToken($accessToken);

-        $this->refreshTokenRepository->persistNewRefreshToken($refreshToken);
+        while ($maxGenerationAttempts-- > 0) {
+            $refreshToken->setIdentifier($this->generateUniqueIdentifier());
+            try {
+                $this->refreshTokenRepository->persistNewRefreshToken($refreshToken);

-        return $refreshToken;
+                return $refreshToken;
+            } catch (UniqueTokenIdentifierConstraintViolationException $e) {
+                if ($maxGenerationAttempts === 0) {
+                    throw $e;
+                }
+            }
+        }
    }

    /**
@@ -366,7 +466,7 @@ abstract class AbstractGrant implements GrantTypeInterface
     *
     * @param int $length
     *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
     *
     * @return string
     */
--- a/src/Grant/AuthCodeGrant.php
+++ b/src/Grant/AuthCodeGrant.php
@@ -9,7 +9,6 @@

 namespace League\OAuth2\Server\Grant;

-use DateInterval;
 use League\OAuth2\Server\Entities\ClientEntityInterface;
 use League\OAuth2\Server\Entities\ScopeEntityInterface;
 use League\OAuth2\Server\Entities\UserEntityInterface;
@@ -30,9 +29,14 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
    private $authCodeTTL;

    /**
-     * @param \League\OAuth2\Server\Repositories\AuthCodeRepositoryInterface     $authCodeRepository
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
-     * @param \DateInterval                                                      $authCodeTTL
+     * @var bool
+     */
+    private $enableCodeExchangeProof = false;
+
+    /**
+     * @param AuthCodeRepositoryInterface     $authCodeRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param \DateInterval                   $authCodeTTL
     */
    public function __construct(
        AuthCodeRepositoryInterface $authCodeRepository,
@@ -45,21 +49,26 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
        $this->refreshTokenTTL = new \DateInterval('P1M');
    }

+    public function enableCodeExchangeProof()
+    {
+        $this->enableCodeExchangeProof = true;
+    }
+
    /**
     * Respond to an access token request.
     *
-     * @param \Psr\Http\Message\ServerRequestInterface                  $request
-     * @param \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface $responseType
-     * @param \DateInterval                                             $accessTokenTTL
+     * @param ServerRequestInterface $request
+     * @param ResponseTypeInterface  $responseType
+     * @param \DateInterval          $accessTokenTTL
     *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
     *
-     * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
+     * @return ResponseTypeInterface
     */
    public function respondToAccessTokenRequest(
        ServerRequestInterface $request,
        ResponseTypeInterface $responseType,
-        DateInterval $accessTokenTTL
+        \DateInterval $accessTokenTTL
    ) {
        // Validate request
        $client = $this->validateClient($request);
@@ -98,7 +107,7 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
            foreach ($authCodePayload->scopes as $scopeId) {
                $scope = $this->scopeRepository->getScopeEntityByIdentifier($scopeId);

-                if (!$scope instanceof ScopeEntityInterface) {
+                if ($scope instanceof ScopeEntityInterface === false) {
                    // @codeCoverageIgnoreStart
                    throw OAuthServerException::invalidScope($scopeId);
                    // @codeCoverageIgnoreEnd
@@ -118,6 +127,42 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
            throw OAuthServerException::invalidRequest('code', 'Cannot decrypt the authorization code');
        }

+        // Validate code challenge
+        if ($this->enableCodeExchangeProof === true) {
+            $codeVerifier = $this->getRequestParameter('code_verifier', $request, null);
+            if ($codeVerifier === null) {
+                throw OAuthServerException::invalidRequest('code_verifier');
+            }
+
+            switch ($authCodePayload->code_challenge_method) {
+                case 'plain':
+                    if (hash_equals($codeVerifier, $authCodePayload->code_challenge) === false) {
+                        throw OAuthServerException::invalidGrant('Failed to verify `code_verifier`.');
+                    }
+
+                    break;
+                case 'S256':
+                    if (
+                        hash_equals(
+                            hash('sha256', strtr(rtrim(base64_encode($codeVerifier), '='), '+/', '-_')),
+                            $authCodePayload->code_challenge
+                        ) === false
+                    ) {
+                        throw OAuthServerException::invalidGrant('Failed to verify `code_verifier`.');
+                    }
+                    // @codeCoverageIgnoreStart
+                    break;
+                default:
+                    throw OAuthServerException::serverError(
+                        sprintf(
+                            'Unsupported code challenge method `%s`',
+                            $authCodePayload->code_challenge_method
+                        )
+                    );
+                // @codeCoverageIgnoreEnd
+            }
+        }
+
        // Issue and persist access + refresh tokens
        $accessToken = $this->issueAccessToken($accessTokenTTL, $client, $authCodePayload->user_id, $scopes);
        $refreshToken = $this->issueRefreshToken($accessToken);
@@ -195,10 +240,15 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
                $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
                throw OAuthServerException::invalidClient();
            }
+        } elseif (is_array($client->getRedirectUri()) && count($client->getRedirectUri()) !== 1
+            || empty($client->getRedirectUri())
+        ) {
+            $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
+            throw OAuthServerException::invalidClient();
        }

        $scopes = $this->validateScopes(
-            $this->getQueryStringParameter('scope', $request),
+            $this->getQueryStringParameter('scope', $request, $this->defaultScope),
            is_array($client->getRedirectUri())
                ? $client->getRedirectUri()[0]
                : $client->getRedirectUri()
@@ -213,6 +263,31 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
        $authorizationRequest->setState($stateParameter);
        $authorizationRequest->setScopes($scopes);

+        if ($this->enableCodeExchangeProof === true) {
+            $codeChallenge = $this->getQueryStringParameter('code_challenge', $request);
+            if ($codeChallenge === null) {
+                throw OAuthServerException::invalidRequest('code_challenge');
+            }
+
+            if (preg_match('/^[A-Za-z0-9-._~]{43,128}$/', $codeChallenge) !== 1) {
+                throw OAuthServerException::invalidRequest(
+                    'code_challenge',
+                    'The code_challenge must be between 43 and 128 characters'
+                );
+            }
+
+            $codeChallengeMethod = $this->getQueryStringParameter('code_challenge_method', $request, 'plain');
+            if (in_array($codeChallengeMethod, ['plain', 'S256']) === false) {
+                throw OAuthServerException::invalidRequest(
+                    'code_challenge_method',
+                    'Code challenge method must be `plain` or `S256`'
+                );
+            }
+
+            $authorizationRequest->setCodeChallenge($codeChallenge);
+            $authorizationRequest->setCodeChallengeMethod($codeChallengeMethod);
+        }
+
        return $authorizationRequest;
    }

@@ -241,6 +316,17 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
                $authorizationRequest->getScopes()
            );

+            $payload = [
+                'client_id'             => $authCode->getClient()->getIdentifier(),
+                'redirect_uri'          => $authCode->getRedirectUri(),
+                'auth_code_id'          => $authCode->getIdentifier(),
+                'scopes'                => $authCode->getScopes(),
+                'user_id'               => $authCode->getUserIdentifier(),
+                'expire_time'           => (new \DateTime())->add($this->authCodeTTL)->format('U'),
+                'code_challenge'        => $authorizationRequest->getCodeChallenge(),
+                'code_challenge_method' => $authorizationRequest->getCodeChallengeMethod(),
+            ];
+
            $response = new RedirectResponse();
            $response->setRedirectUri(
                $this->makeRedirectUri(
@@ -248,14 +334,7 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
                    [
                        'code'  => $this->encrypt(
                            json_encode(
-                                [
-                                    'client_id'    => $authCode->getClient()->getIdentifier(),
-                                    'redirect_uri' => $authCode->getRedirectUri(),
-                                    'auth_code_id' => $authCode->getIdentifier(),
-                                    'scopes'       => $authCode->getScopes(),
-                                    'user_id'      => $authCode->getUserIdentifier(),
-                                    'expire_time'  => (new \DateTime())->add($this->authCodeTTL)->format('U'),
-                                ]
+                                $payload
                            )
                        ),
                        'state' => $authorizationRequest->getState(),
@@ -269,7 +348,12 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
        // The user denied the client, redirect them back with an error
        throw OAuthServerException::accessDenied(
            'The user denied the request',
-            $finalRedirectUri
+            $this->makeRedirectUri(
+                $finalRedirectUri,
+                [
+                    'state' => $authorizationRequest->getState(),
+                ]
+            )
        );
    }
 }
--- a/src/Grant/ClientCredentialsGrant.php
+++ b/src/Grant/ClientCredentialsGrant.php
@@ -8,6 +8,7 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\Grant;

 use League\OAuth2\Server\ResponseTypes\ResponseTypeInterface;
@@ -28,13 +29,13 @@ class ClientCredentialsGrant extends AbstractGrant
    ) {
        // Validate request
        $client = $this->validateClient($request);
-        $scopes = $this->validateScopes($this->getRequestParameter('scope', $request));
+        $scopes = $this->validateScopes($this->getRequestParameter('scope', $request, $this->defaultScope));

        // Finalize the requested scopes
-        $scopes = $this->scopeRepository->finalizeScopes($scopes, $this->getIdentifier(), $client);
+        $finalizedScopes = $this->scopeRepository->finalizeScopes($scopes, $this->getIdentifier(), $client);

        // Issue and persist access token
-        $accessToken = $this->issueAccessToken($accessTokenTTL, $client, null, $scopes);
+        $accessToken = $this->issueAccessToken($accessTokenTTL, $client, null, $finalizedScopes);

        // Inject access token into response type
        $responseType->setAccessToken($accessToken);
--- a/src/Grant/GrantTypeInterface.php
+++ b/src/Grant/GrantTypeInterface.php
@@ -8,6 +8,7 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\Grant;

 use League\Event\EmitterAwareInterface;
@@ -41,11 +42,11 @@ interface GrantTypeInterface extends EmitterAwareInterface
    /**
     * Respond to an incoming request.
     *
-     * @param \Psr\Http\Message\ServerRequestInterface                  $request
-     * @param \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface $responseType
-     * @param \DateInterval                                             $accessTokenTTL
+     * @param ServerRequestInterface $request
+     * @param ResponseTypeInterface  $responseType
+     * @param \DateInterval          $accessTokenTTL
     *
-     * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
+     * @return ResponseTypeInterface
     */
    public function respondToAccessTokenRequest(
        ServerRequestInterface $request,
@@ -56,7 +57,7 @@ interface GrantTypeInterface extends EmitterAwareInterface
    /**
     * The grant type should return true if it is able to response to an authorization request
     *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
     *
     * @return bool
     */
@@ -69,7 +70,7 @@ interface GrantTypeInterface extends EmitterAwareInterface
     * If the validation is successful an AuthorizationRequest object will be returned. This object can be safely
     * serialized in a user's session, and can be used during user authentication and authorization.
     *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
     *
     * @return AuthorizationRequest
     */
@@ -80,9 +81,9 @@ interface GrantTypeInterface extends EmitterAwareInterface
     * The AuthorizationRequest object's $userId property must be set to the authenticated user and the
     * $authorizationApproved property must reflect their desire to authorize or deny the client.
     *
-     * @param \League\OAuth2\Server\RequestTypes\AuthorizationRequest $authorizationRequest
+     * @param AuthorizationRequest $authorizationRequest
     *
-     * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
+     * @return ResponseTypeInterface
     */
    public function completeAuthorizationRequest(AuthorizationRequest $authorizationRequest);

@@ -91,7 +92,7 @@ interface GrantTypeInterface extends EmitterAwareInterface
     *
     * For example most grant types will check that the $_POST['grant_type'] property matches it's identifier property.
     *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
     *
     * @return bool
     */
@@ -100,35 +101,42 @@ interface GrantTypeInterface extends EmitterAwareInterface
    /**
     * Set the client repository.
     *
-     * @param \League\OAuth2\Server\Repositories\ClientRepositoryInterface $clientRepository
+     * @param ClientRepositoryInterface $clientRepository
     */
    public function setClientRepository(ClientRepositoryInterface $clientRepository);

    /**
     * Set the access token repository.
     *
-     * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface $accessTokenRepository
+     * @param AccessTokenRepositoryInterface $accessTokenRepository
     */
    public function setAccessTokenRepository(AccessTokenRepositoryInterface $accessTokenRepository);

    /**
     * Set the scope repository.
     *
-     * @param \League\OAuth2\Server\Repositories\ScopeRepositoryInterface $scopeRepository
+     * @param ScopeRepositoryInterface $scopeRepository
     */
    public function setScopeRepository(ScopeRepositoryInterface $scopeRepository);

+    /**
+     * Set the default scope.
+     *
+     * @param string $scope
+     */
+    public function setDefaultScope($scope);
+
    /**
     * Set the path to the private key.
     *
-     * @param \League\OAuth2\Server\CryptKey $privateKey
+     * @param CryptKey $privateKey
     */
    public function setPrivateKey(CryptKey $privateKey);

    /**
-     * Set the path to the public key.
+     * Set the encryption key
     *
-     * @param \League\OAuth2\Server\CryptKey $publicKey
+     * @param string|null $key
     */
-    public function setPublicKey(CryptKey $publicKey);
+    public function setEncryptionKey($key = null);
 }
--- a/src/Grant/ImplicitGrant.php
+++ b/src/Grant/ImplicitGrant.php
@@ -27,11 +27,18 @@ class ImplicitGrant extends AbstractAuthorizeGrant
    private $accessTokenTTL;

    /**
-     * @param \DateInterval $accessTokenTTL
+     * @var string
     */
-    public function __construct(\DateInterval $accessTokenTTL)
+    private $queryDelimiter;
+
+    /**
+     * @param \DateInterval $accessTokenTTL
+     * @param string $queryDelimiter
+     */
+    public function __construct(\DateInterval $accessTokenTTL, $queryDelimiter = '#')
    {
        $this->accessTokenTTL = $accessTokenTTL;
+        $this->queryDelimiter = $queryDelimiter;
    }

    /**
@@ -45,7 +52,7 @@ class ImplicitGrant extends AbstractAuthorizeGrant
    }

    /**
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
     *
     * @throw \LogicException
     */
@@ -75,11 +82,11 @@ class ImplicitGrant extends AbstractAuthorizeGrant
    /**
     * Respond to an incoming request.
     *
-     * @param \Psr\Http\Message\ServerRequestInterface                  $request
-     * @param \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface $responseType
-     * @param \DateInterval                                             $accessTokenTTL
+     * @param ServerRequestInterface $request
+     * @param ResponseTypeInterface  $responseType
+     * @param \DateInterval          $accessTokenTTL
     *
-     * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
+     * @return ResponseTypeInterface
     */
    public function respondToAccessTokenRequest(
        ServerRequestInterface $request,
@@ -95,7 +102,7 @@ class ImplicitGrant extends AbstractAuthorizeGrant
    public function canRespondToAuthorizationRequest(ServerRequestInterface $request)
    {
        return (
-            array_key_exists('response_type', $request->getQueryParams())
+            isset($request->getQueryParams()['response_type'])
            && $request->getQueryParams()['response_type'] === 'token'
            && isset($request->getQueryParams()['client_id'])
        );
@@ -142,15 +149,27 @@ class ImplicitGrant extends AbstractAuthorizeGrant
                $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
                throw OAuthServerException::invalidClient();
            }
+        } elseif (is_array($client->getRedirectUri()) && count($client->getRedirectUri()) !== 1
+            || empty($client->getRedirectUri())
+        ) {
+            $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
+            throw OAuthServerException::invalidClient();
        }

        $scopes = $this->validateScopes(
-            $this->getQueryStringParameter('scope', $request),
+            $this->getQueryStringParameter('scope', $request, $this->defaultScope),
            is_array($client->getRedirectUri())
                ? $client->getRedirectUri()[0]
                : $client->getRedirectUri()
        );

+        // Finalize the requested scopes
+        $finalizedScopes = $this->scopeRepository->finalizeScopes(
+            $scopes,
+            $this->getIdentifier(),
+            $client
+        );
+
        $stateParameter = $this->getQueryStringParameter('state', $request);

        $authorizationRequest = new AuthorizationRequest();
@@ -158,7 +177,7 @@ class ImplicitGrant extends AbstractAuthorizeGrant
        $authorizationRequest->setClient($client);
        $authorizationRequest->setRedirectUri($redirectUri);
        $authorizationRequest->setState($stateParameter);
-        $authorizationRequest->setScopes($scopes);
+        $authorizationRequest->setScopes($finalizedScopes);

        return $authorizationRequest;
    }
@@ -193,11 +212,11 @@ class ImplicitGrant extends AbstractAuthorizeGrant
                    $finalRedirectUri,
                    [
                        'access_token' => (string) $accessToken->convertToJWT($this->privateKey),
-                        'token_type'   => 'bearer',
+                        'token_type'   => 'Bearer',
                        'expires_in'   => $accessToken->getExpiryDateTime()->getTimestamp() - (new \DateTime())->getTimestamp(),
                        'state'        => $authorizationRequest->getState(),
                    ],
-                    '#'
+                    $this->queryDelimiter
                )
            );

@@ -207,7 +226,12 @@ class ImplicitGrant extends AbstractAuthorizeGrant
        // The user denied the client, redirect them back with an error
        throw OAuthServerException::accessDenied(
            'The user denied the request',
-            $finalRedirectUri
+            $this->makeRedirectUri(
+                $finalRedirectUri,
+                [
+                    'state' => $authorizationRequest->getState(),
+                ]
+            )
        );
    }
 }
--- a/src/Grant/PasswordGrant.php
+++ b/src/Grant/PasswordGrant.php
@@ -8,6 +8,7 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\Grant;

 use League\OAuth2\Server\Entities\ClientEntityInterface;
@@ -25,8 +26,8 @@ use Psr\Http\Message\ServerRequestInterface;
 class PasswordGrant extends AbstractGrant
 {
    /**
-     * @param \League\OAuth2\Server\Repositories\UserRepositoryInterface         $userRepository
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param UserRepositoryInterface         $userRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
     */
    public function __construct(
        UserRepositoryInterface $userRepository,
@@ -48,14 +49,14 @@ class PasswordGrant extends AbstractGrant
    ) {
        // Validate request
        $client = $this->validateClient($request);
-        $scopes = $this->validateScopes($this->getRequestParameter('scope', $request));
+        $scopes = $this->validateScopes($this->getRequestParameter('scope', $request, $this->defaultScope));
        $user = $this->validateUser($request, $client);

        // Finalize the requested scopes
-        $scopes = $this->scopeRepository->finalizeScopes($scopes, $this->getIdentifier(), $client, $user->getIdentifier());
+        $finalizedScopes = $this->scopeRepository->finalizeScopes($scopes, $this->getIdentifier(), $client, $user->getIdentifier());

        // Issue and persist new tokens
-        $accessToken = $this->issueAccessToken($accessTokenTTL, $client, $user->getIdentifier(), $scopes);
+        $accessToken = $this->issueAccessToken($accessTokenTTL, $client, $user->getIdentifier(), $finalizedScopes);
        $refreshToken = $this->issueRefreshToken($accessToken);

        // Inject tokens into response
@@ -66,12 +67,12 @@ class PasswordGrant extends AbstractGrant
    }

    /**
-     * @param \Psr\Http\Message\ServerRequestInterface             $request
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $client
+     * @param ServerRequestInterface $request
+     * @param ClientEntityInterface  $client
     *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
     *
-     * @return \League\OAuth2\Server\Entities\UserEntityInterface
+     * @return UserEntityInterface
     */
    protected function validateUser(ServerRequestInterface $request, ClientEntityInterface $client)
    {
@@ -91,7 +92,7 @@ class PasswordGrant extends AbstractGrant
            $this->getIdentifier(),
            $client
        );
-        if (!$user instanceof UserEntityInterface) {
+        if ($user instanceof UserEntityInterface === false) {
            $this->getEmitter()->emit(new RequestEvent(RequestEvent::USER_AUTHENTICATION_FAILED, $request));

            throw OAuthServerException::invalidCredentials();
--- a/src/Grant/RefreshTokenGrant.php
+++ b/src/Grant/RefreshTokenGrant.php
@@ -8,6 +8,7 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\Grant;

 use League\OAuth2\Server\Entities\ScopeEntityInterface;
@@ -23,7 +24,7 @@ use Psr\Http\Message\ServerRequestInterface;
 class RefreshTokenGrant extends AbstractGrant
 {
    /**
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
     */
    public function __construct(RefreshTokenRepositoryInterface $refreshTokenRepository)
    {
@@ -43,28 +44,17 @@ class RefreshTokenGrant extends AbstractGrant
        // Validate request
        $client = $this->validateClient($request);
        $oldRefreshToken = $this->validateOldRefreshToken($request, $client->getIdentifier());
-        $scopes = $this->validateScopes($this->getRequestParameter('scope', $request));
+        $scopes = $this->validateScopes($this->getRequestParameter(
+            'scope',
+            $request,
+            implode(self::SCOPE_DELIMITER_STRING, $oldRefreshToken['scopes']))
+        );

-        // If no new scopes are requested then give the access token the original session scopes
-        if (count($scopes) === 0) {
-            $scopes = array_map(function ($scopeId) use ($client) {
-                $scope = $this->scopeRepository->getScopeEntityByIdentifier($scopeId);
-
-                if (!$scope instanceof ScopeEntityInterface) {
-                    // @codeCoverageIgnoreStart
-                    throw OAuthServerException::invalidScope($scopeId);
-                    // @codeCoverageIgnoreEnd
-                }
-
-                return $scope;
-            }, $oldRefreshToken['scopes']);
-        } else {
-            // The OAuth spec says that a refreshed access token can have the original scopes or fewer so ensure
-            // the request doesn't include any new scopes
-            foreach ($scopes as $scope) {
-                if (in_array($scope->getIdentifier(), $oldRefreshToken['scopes']) === false) {
-                    throw OAuthServerException::invalidScope($scope->getIdentifier());
-                }
+        // The OAuth spec says that a refreshed access token can have the original scopes or fewer so ensure
+        // the request doesn't include any new scopes
+        foreach ($scopes as $scope) {
+            if (in_array($scope->getIdentifier(), $oldRefreshToken['scopes']) === false) {
+                throw OAuthServerException::invalidScope($scope->getIdentifier());
            }
        }

@@ -84,10 +74,10 @@ class RefreshTokenGrant extends AbstractGrant
    }

    /**
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param string                                   $clientId
+     * @param ServerRequestInterface $request
+     * @param string                 $clientId
     *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
     *
     * @return array
     */
@@ -101,7 +91,7 @@ class RefreshTokenGrant extends AbstractGrant
        // Validate refresh token
        try {
            $refreshToken = $this->decrypt($encryptedRefreshToken);
-        } catch (\LogicException $e) {
+        } catch (\Exception $e) {
            throw OAuthServerException::invalidRefreshToken('Cannot decrypt the refresh token');
        }

--- a/src/Middleware/AuthorizationServerMiddleware.php
+++ b/src/Middleware/AuthorizationServerMiddleware.php
@@ -17,14 +17,12 @@ use Psr\Http\Message\ServerRequestInterface;
 class AuthorizationServerMiddleware
 {
    /**
-     * @var \League\OAuth2\Server\AuthorizationServer
+     * @var AuthorizationServer
     */
    private $server;

    /**
-     * AuthorizationServerMiddleware constructor.
-     *
-     * @param \League\OAuth2\Server\AuthorizationServer $server
+     * @param AuthorizationServer $server
     */
    public function __construct(AuthorizationServer $server)
    {
@@ -32,11 +30,11 @@ class AuthorizationServerMiddleware
    }

    /**
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param \Psr\Http\Message\ResponseInterface      $response
-     * @param callable                                 $next
+     * @param ServerRequestInterface $request
+     * @param ResponseInterface      $response
+     * @param callable               $next
     *
-     * @return \Psr\Http\Message\ResponseInterface
+     * @return ResponseInterface
     */
    public function __invoke(ServerRequestInterface $request, ResponseInterface $response, callable $next)
    {
@@ -46,9 +44,8 @@ class AuthorizationServerMiddleware
            return $exception->generateHttpResponse($response);
            // @codeCoverageIgnoreStart
        } catch (\Exception $exception) {
-            $response->getBody()->write($exception->getMessage());
-
-            return $response->withStatus(500);
+            return (new OAuthServerException($exception->getMessage(), 0, 'unknown_error', 500))
+                ->generateHttpResponse($response);
            // @codeCoverageIgnoreEnd
        }

--- a/src/Middleware/ResourceServerMiddleware.php
+++ b/src/Middleware/ResourceServerMiddleware.php
@@ -17,14 +17,12 @@ use Psr\Http\Message\ServerRequestInterface;
 class ResourceServerMiddleware
 {
    /**
-     * @var \League\OAuth2\Server\ResourceServer
+     * @var ResourceServer
     */
    private $server;

    /**
-     * ResourceServerMiddleware constructor.
-     *
-     * @param \League\OAuth2\Server\ResourceServer $server
+     * @param ResourceServer $server
     */
    public function __construct(ResourceServer $server)
    {
@@ -32,9 +30,9 @@ class ResourceServerMiddleware
    }

    /**
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param \Psr\Http\Message\ResponseInterface      $response
-     * @param callable                                 $next
+     * @param ServerRequestInterface $request
+     * @param ResponseInterface      $response
+     * @param callable               $next
     *
     * @return \Psr\Http\Message\ResponseInterface
     */
@@ -46,9 +44,8 @@ class ResourceServerMiddleware
            return $exception->generateHttpResponse($response);
            // @codeCoverageIgnoreStart
        } catch (\Exception $exception) {
-            $response->getBody()->write($exception->getMessage());
-
-            return $response->withStatus(500);
+            return (new OAuthServerException($exception->getMessage(), 0, 'unknown_error', 500))
+                ->generateHttpResponse($response);
            // @codeCoverageIgnoreEnd
        }

--- a/src/Repositories/AccessTokenRepositoryInterface.php
+++ b/src/Repositories/AccessTokenRepositoryInterface.php
@@ -11,6 +11,8 @@ namespace League\OAuth2\Server\Repositories;

 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\ClientEntityInterface;
+use League\OAuth2\Server\Entities\ScopeEntityInterface;
+use League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException;

 /**
 * Access token interface.
@@ -20,9 +22,9 @@ interface AccessTokenRepositoryInterface extends RepositoryInterface
    /**
     * Create a new access token
     *
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface  $clientEntity
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface[] $scopes
-     * @param mixed                                                 $userIdentifier
+     * @param ClientEntityInterface  $clientEntity
+     * @param ScopeEntityInterface[] $scopes
+     * @param mixed                  $userIdentifier
     *
     * @return AccessTokenEntityInterface
     */
@@ -31,7 +33,9 @@ interface AccessTokenRepositoryInterface extends RepositoryInterface
    /**
     * Persists a new access token to permanent storage.
     *
-     * @param \League\OAuth2\Server\Entities\AccessTokenEntityInterface $accessTokenEntity
+     * @param AccessTokenEntityInterface $accessTokenEntity
+     *
+     * @throws UniqueTokenIdentifierConstraintViolationException
     */
    public function persistNewAccessToken(AccessTokenEntityInterface $accessTokenEntity);

--- a/src/Repositories/AuthCodeRepositoryInterface.php
+++ b/src/Repositories/AuthCodeRepositoryInterface.php
@@ -6,9 +6,11 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\Repositories;

 use League\OAuth2\Server\Entities\AuthCodeEntityInterface;
+use League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException;

 /**
 * Auth code storage interface.
@@ -18,14 +20,16 @@ interface AuthCodeRepositoryInterface extends RepositoryInterface
    /**
     * Creates a new AuthCode
     *
-     * @return \League\OAuth2\Server\Entities\AuthCodeEntityInterface
+     * @return AuthCodeEntityInterface
     */
    public function getNewAuthCode();

    /**
     * Persists a new auth code to permanent storage.
     *
-     * @param \League\OAuth2\Server\Entities\AuthCodeEntityInterface $authCodeEntity
+     * @param AuthCodeEntityInterface $authCodeEntity
+     *
+     * @throws UniqueTokenIdentifierConstraintViolationException
     */
    public function persistNewAuthCode(AuthCodeEntityInterface $authCodeEntity);

--- a/src/Repositories/ClientRepositoryInterface.php
+++ b/src/Repositories/ClientRepositoryInterface.php
@@ -6,8 +6,11 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\Repositories;

+use League\OAuth2\Server\Entities\ClientEntityInterface;
+
 /**
 * Client storage interface.
 */
@@ -19,10 +22,10 @@ interface ClientRepositoryInterface extends RepositoryInterface
     * @param string      $clientIdentifier   The client's identifier
     * @param string      $grantType          The grant type used
     * @param null|string $clientSecret       The client's secret (if sent)
-     * @param bool        $mustValidateSecret If true the client must attempt to validate the secret unless the client
+     * @param bool        $mustValidateSecret If true the client must attempt to validate the secret if the client
     *                                        is confidential
     *
-     * @return \League\OAuth2\Server\Entities\ClientEntityInterface
+     * @return ClientEntityInterface
     */
    public function getClientEntity($clientIdentifier, $grantType, $clientSecret = null, $mustValidateSecret = true);
 }
--- a/src/Repositories/RefreshTokenRepositoryInterface.php
+++ b/src/Repositories/RefreshTokenRepositoryInterface.php
@@ -6,9 +6,11 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\Repositories;

 use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
+use League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException;

 /**
 * Refresh token interface.
@@ -25,7 +27,9 @@ interface RefreshTokenRepositoryInterface extends RepositoryInterface
    /**
     * Create a new refresh token_name.
     *
-     * @param \League\OAuth2\Server\Entities\RefreshTokenEntityInterface $refreshTokenEntity
+     * @param RefreshTokenEntityInterface $refreshTokenEntity
+     *
+     * @throws UniqueTokenIdentifierConstraintViolationException
     */
    public function persistNewRefreshToken(RefreshTokenEntityInterface $refreshTokenEntity);

--- a/src/Repositories/RepositoryInterface.php
+++ b/src/Repositories/RepositoryInterface.php
@@ -6,6 +6,7 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\Repositories;

 /**
--- a/src/Repositories/ScopeRepositoryInterface.php
+++ b/src/Repositories/ScopeRepositoryInterface.php
@@ -22,7 +22,7 @@ interface ScopeRepositoryInterface extends RepositoryInterface
     *
     * @param string $identifier The scope identifier
     *
-     * @return \League\OAuth2\Server\Entities\ScopeEntityInterface
+     * @return ScopeEntityInterface
     */
    public function getScopeEntityByIdentifier($identifier);

@@ -30,12 +30,12 @@ interface ScopeRepositoryInterface extends RepositoryInterface
     * Given a client, grant type and optional user identifier validate the set of scopes requested are valid and optionally
     * append additional scopes or remove requested scopes.
     *
-     * @param ScopeEntityInterface[]                               $scopes
-     * @param string                                               $grantType
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $clientEntity
-     * @param null|string                                          $userIdentifier
+     * @param ScopeEntityInterface[] $scopes
+     * @param string                 $grantType
+     * @param ClientEntityInterface  $clientEntity
+     * @param null|string            $userIdentifier
     *
-     * @return \League\OAuth2\Server\Entities\ScopeEntityInterface[]
+     * @return ScopeEntityInterface[]
     */
    public function finalizeScopes(
        array $scopes,
--- a/src/Repositories/UserRepositoryInterface.php
+++ b/src/Repositories/UserRepositoryInterface.php
@@ -10,18 +10,19 @@
 namespace League\OAuth2\Server\Repositories;

 use League\OAuth2\Server\Entities\ClientEntityInterface;
+use League\OAuth2\Server\Entities\UserEntityInterface;

 interface UserRepositoryInterface extends RepositoryInterface
 {
    /**
     * Get a user entity.
     *
-     * @param string                                               $username
-     * @param string                                               $password
-     * @param string                                               $grantType    The grant type used
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $clientEntity
+     * @param string                $username
+     * @param string                $password
+     * @param string                $grantType    The grant type used
+     * @param ClientEntityInterface $clientEntity
     *
-     * @return \League\OAuth2\Server\Entities\UserEntityInterface
+     * @return UserEntityInterface
     */
    public function getUserEntityByUserCredentials(
        $username,
--- a/src/RequestEvent.php
+++ b/src/RequestEvent.php
@@ -6,6 +6,7 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server;

 use League\Event\Event;
@@ -18,15 +19,15 @@ class RequestEvent extends Event
    const REFRESH_TOKEN_CLIENT_FAILED = 'refresh_token.client.failed';

    /**
-     * @var \Psr\Http\Message\ServerRequestInterface
+     * @var ServerRequestInterface
     */
    private $request;

    /**
     * RequestEvent constructor.
     *
-     * @param string                                   $name
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param string                 $name
+     * @param ServerRequestInterface $request
     */
    public function __construct($name, ServerRequestInterface $request)
    {
--- a/src/RequestTypes/AuthorizationRequest.php
+++ b/src/RequestTypes/AuthorizationRequest.php
@@ -64,6 +64,20 @@ class AuthorizationRequest
     */
    protected $state;

+    /**
+     * The code challenge (if provided)
+     *
+     * @var string
+     */
+    protected $codeChallenge;
+
+    /**
+     * The code challenge method (if provided)
+     *
+     * @var string
+     */
+    protected $codeChallengeMethod;
+
    /**
     * @return string
     */
@@ -113,7 +127,7 @@ class AuthorizationRequest
    }

    /**
-     * @return \League\OAuth2\Server\Entities\ScopeEntityInterface[]
+     * @return ScopeEntityInterface[]
     */
    public function getScopes()
    {
@@ -121,9 +135,9 @@ class AuthorizationRequest
    }

    /**
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface[] $scopes
+     * @param ScopeEntityInterface[] $scopes
     */
-    public function setScopes($scopes)
+    public function setScopes(array $scopes)
    {
        $this->scopes = $scopes;
    }
@@ -175,4 +189,36 @@ class AuthorizationRequest
    {
        $this->state = $state;
    }
+
+    /**
+     * @return string
+     */
+    public function getCodeChallenge()
+    {
+        return $this->codeChallenge;
+    }
+
+    /**
+     * @param string $codeChallenge
+     */
+    public function setCodeChallenge($codeChallenge)
+    {
+        $this->codeChallenge = $codeChallenge;
+    }
+
+    /**
+     * @return string
+     */
+    public function getCodeChallengeMethod()
+    {
+        return $this->codeChallengeMethod;
+    }
+
+    /**
+     * @param string $codeChallengeMethod
+     */
+    public function setCodeChallengeMethod($codeChallengeMethod)
+    {
+        $this->codeChallengeMethod = $codeChallengeMethod;
+    }
 }
--- a/src/ResourceServer.php
+++ b/src/ResourceServer.php
@@ -6,34 +6,38 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server;

 use League\OAuth2\Server\AuthorizationValidators\AuthorizationValidatorInterface;
 use League\OAuth2\Server\AuthorizationValidators\BearerTokenValidator;
+use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use Psr\Http\Message\ServerRequestInterface;

 class ResourceServer
 {
    /**
-     * @var \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface
+     * @var AccessTokenRepositoryInterface
     */
    private $accessTokenRepository;
+
    /**
-     * @var \League\OAuth2\Server\CryptKey|string
+     * @var CryptKey
     */
    private $publicKey;
+
    /**
-     * @var \League\OAuth2\Server\AuthorizationValidators\AuthorizationValidatorInterface|null
+     * @var null|AuthorizationValidatorInterface
     */
    private $authorizationValidator;

    /**
     * New server instance.
     *
-     * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface                  $accessTokenRepository
-     * @param \League\OAuth2\Server\CryptKey|string                                              $publicKey
-     * @param null|\League\OAuth2\Server\AuthorizationValidators\AuthorizationValidatorInterface $authorizationValidator
+     * @param AccessTokenRepositoryInterface       $accessTokenRepository
+     * @param CryptKey|string                      $publicKey
+     * @param null|AuthorizationValidatorInterface $authorizationValidator
     */
    public function __construct(
        AccessTokenRepositoryInterface $accessTokenRepository,
@@ -42,7 +46,7 @@ class ResourceServer
    ) {
        $this->accessTokenRepository = $accessTokenRepository;

-        if (!$publicKey instanceof CryptKey) {
+        if ($publicKey instanceof CryptKey === false) {
            $publicKey = new CryptKey($publicKey);
        }
        $this->publicKey = $publicKey;
@@ -51,11 +55,11 @@ class ResourceServer
    }

    /**
-     * @return \League\OAuth2\Server\AuthorizationValidators\AuthorizationValidatorInterface
+     * @return AuthorizationValidatorInterface
     */
    protected function getAuthorizationValidator()
    {
-        if (!$this->authorizationValidator instanceof AuthorizationValidatorInterface) {
+        if ($this->authorizationValidator instanceof AuthorizationValidatorInterface === false) {
            $this->authorizationValidator = new BearerTokenValidator($this->accessTokenRepository);
        }

@@ -67,11 +71,11 @@ class ResourceServer
    /**
     * Determine the access token validity.
     *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
     *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
     *
-     * @return \Psr\Http\Message\ServerRequestInterface
+     * @return ServerRequestInterface
     */
    public function validateAuthenticatedRequest(ServerRequestInterface $request)
    {
--- a/src/ResponseTypes/AbstractResponseType.php
+++ b/src/ResponseTypes/AbstractResponseType.php
@@ -8,8 +8,10 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\ResponseTypes;

+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\CryptTrait;
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
@@ -19,15 +21,20 @@ abstract class AbstractResponseType implements ResponseTypeInterface
    use CryptTrait;

    /**
-     * @var \League\OAuth2\Server\Entities\AccessTokenEntityInterface
+     * @var AccessTokenEntityInterface
     */
    protected $accessToken;

    /**
-     * @var \League\OAuth2\Server\Entities\RefreshTokenEntityInterface
+     * @var RefreshTokenEntityInterface
     */
    protected $refreshToken;

+    /**
+     * @var CryptKey
+     */
+    protected $privateKey;
+
    /**
     * {@inheritdoc}
     */
@@ -43,4 +50,14 @@ abstract class AbstractResponseType implements ResponseTypeInterface
    {
        $this->refreshToken = $refreshToken;
    }
+
+    /**
+     * Set the private key
+     *
+     * @param \League\OAuth2\Server\CryptKey $key
+     */
+    public function setPrivateKey(CryptKey $key)
+    {
+        $this->privateKey = $key;
+    }
 }
--- a/src/ResponseTypes/BearerTokenResponse.php
+++ b/src/ResponseTypes/BearerTokenResponse.php
@@ -1,6 +1,6 @@
 <?php
 /**
- * OAuth 2.0 Bearer Token Type.
+ * OAuth 2.0 Bearer Token Response.
 *
 * @author      Alex Bilbie <hello@alexbilbie.com>
 * @copyright   Copyright (c) Alex Bilbie
@@ -8,8 +8,10 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\ResponseTypes;

+use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
 use Psr\Http\Message\ResponseInterface;

@@ -47,6 +49,8 @@ class BearerTokenResponse extends AbstractResponseType
            $responseParams['refresh_token'] = $refreshToken;
        }

+        $responseParams = array_merge($this->getExtraParams($this->accessToken), $responseParams);
+
        $response = $response
            ->withStatus(200)
            ->withHeader('pragma', 'no-cache')
@@ -57,4 +61,18 @@ class BearerTokenResponse extends AbstractResponseType

        return $response;
    }
+
+    /**
+     * Add custom fields to your Bearer Token response here, then override
+     * AuthorizationServer::getResponseType() to pull in your version of
+     * this class rather than the default.
+     *
+     * @param AccessTokenEntityInterface $accessToken
+     *
+     * @return array
+     */
+    protected function getExtraParams(AccessTokenEntityInterface $accessToken)
+    {
+        return [];
+    }
 }
--- a/src/ResponseTypes/RedirectResponse.php
+++ b/src/ResponseTypes/RedirectResponse.php
@@ -1,4 +1,13 @@
 <?php
+/**
+ * OAuth 2.0 Redirect Response.
+ *
+ * @author      Alex Bilbie <hello@alexbilbie.com>
+ * @copyright   Copyright (c) Alex Bilbie
+ * @license     http://mit-license.org/
+ *
+ * @link        https://github.com/thephpleague/oauth2-server
+ */

 namespace League\OAuth2\Server\ResponseTypes;

--- a/src/ResponseTypes/ResponseTypeInterface.php
+++ b/src/ResponseTypes/ResponseTypeInterface.php
@@ -8,6 +8,7 @@
 *
 * @link        https://github.com/thephpleague/oauth2-server
 */
+
 namespace League\OAuth2\Server\ResponseTypes;

 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
@@ -17,12 +18,12 @@ use Psr\Http\Message\ResponseInterface;
 interface ResponseTypeInterface
 {
    /**
-     * @param \League\OAuth2\Server\Entities\AccessTokenEntityInterface $accessToken
+     * @param AccessTokenEntityInterface $accessToken
     */
    public function setAccessToken(AccessTokenEntityInterface $accessToken);

    /**
-     * @param \League\OAuth2\Server\Entities\RefreshTokenEntityInterface $refreshToken
+     * @param RefreshTokenEntityInterface $refreshToken
     */
    public function setRefreshToken(RefreshTokenEntityInterface $refreshToken);

@@ -32,4 +33,11 @@ interface ResponseTypeInterface
     * @return ResponseInterface
     */
    public function generateHttpResponse(ResponseInterface $response);
+
+    /**
+     * Set the encryption key
+     *
+     * @param string|null $key
+     */
+    public function setEncryptionKey($key = null);
 }
--- a/tests/AuthorizationServerTest.php
+++ b/tests/AuthorizationServerTest.php
@@ -3,7 +3,6 @@
 namespace LeagueTests;

 use League\OAuth2\Server\AuthorizationServer;
-use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Grant\AuthCodeGrant;
 use League\OAuth2\Server\Grant\ClientCredentialsGrant;
@@ -17,23 +16,35 @@ use League\OAuth2\Server\ResponseTypes\BearerTokenResponse;
 use LeagueTests\Stubs\AccessTokenEntity;
 use LeagueTests\Stubs\AuthCodeEntity;
 use LeagueTests\Stubs\ClientEntity;
+use LeagueTests\Stubs\ScopeEntity;
 use LeagueTests\Stubs\StubResponseType;
 use LeagueTests\Stubs\UserEntity;
 use Psr\Http\Message\ResponseInterface;
+use PHPUnit\Framework\TestCase;
 use Zend\Diactoros\Response;
 use Zend\Diactoros\ServerRequest;
 use Zend\Diactoros\ServerRequestFactory;

-class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
+class AuthorizationServerTest extends TestCase
 {
+
+    const DEFAULT_SCOPE = 'basic';
+
+    public function setUp()
+    {
+        // Make sure the keys have the correct permissions.
+        chmod(__DIR__ . '/Stubs/private.key', 0600);
+        chmod(__DIR__ . '/Stubs/public.key', 0600);
+    }
+
    public function testRespondToRequestInvalidGrantType()
    {
        $server = new AuthorizationServer(
-            $this->getMock(ClientRepositoryInterface::class),
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(ClientRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
            'file://' . __DIR__ . '/Stubs/private.key',
-            'file://' . __DIR__ . '/Stubs/public.key',
+            base64_encode(random_bytes(36)),
            new StubResponseType()
        );

@@ -49,13 +60,15 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase

    public function testRespondToRequest()
    {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
        $clientRepository->method('getClientEntity')->willReturn(new ClientEntity());

+        $scope = new ScopeEntity();
        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scope);
        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);

-        $accessTokenRepositoryMock = $this->getMock(AccessTokenRepositoryInterface::class);
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());

        $server = new AuthorizationServer(
@@ -63,10 +76,11 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
            $accessTokenRepositoryMock,
            $scopeRepositoryMock,
            'file://' . __DIR__ . '/Stubs/private.key',
-            'file://' . __DIR__ . '/Stubs/public.key',
+            base64_encode(random_bytes(36)),
            new StubResponseType()
        );

+        $server->setDefaultScope(self::DEFAULT_SCOPE);
        $server->enableGrantType(new ClientCredentialsGrant(), new \DateInterval('PT1M'));

        $_POST['grant_type'] = 'client_credentials';
@@ -78,12 +92,12 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase

    public function testGetResponseType()
    {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();

        $server = new AuthorizationServer(
            $clientRepository,
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
            'file://' . __DIR__ . '/Stubs/private.key',
            'file://' . __DIR__ . '/Stubs/public.key'
        );
@@ -92,17 +106,17 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
        $method = $abstractGrantReflection->getMethod('getResponseType');
        $method->setAccessible(true);

-        $this->assertTrue($method->invoke($server) instanceof BearerTokenResponse);
+        $this->assertInstanceOf(BearerTokenResponse::class, $method->invoke($server));
    }

    public function testCompleteAuthorizationRequest()
    {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();

        $server = new AuthorizationServer(
            $clientRepository,
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
            'file://' . __DIR__ . '/Stubs/private.key',
            'file://' . __DIR__ . '/Stubs/public.key'
        );
@@ -112,13 +126,10 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase

        $grant = new AuthCodeGrant(
            $authCodeRepository,
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
            new \DateInterval('PT10M')
        );

-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/Stubs/private.key'));
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/Stubs/public.key'));
-
        $server->enableGrantType($grant);

        $authRequest = new AuthorizationRequest();
@@ -127,12 +138,59 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
        $authRequest->setGrantTypeId('authorization_code');
        $authRequest->setUser(new UserEntity());

-        $this->assertTrue(
-            $server->completeAuthorizationRequest($authRequest, new Response) instanceof ResponseInterface
+        $this->assertInstanceOf(
+            ResponseInterface::class,
+            $server->completeAuthorizationRequest($authRequest, new Response)
        );
    }

    public function testValidateAuthorizationRequest()
+    {
+        $client = new ClientEntity();
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $scope = new ScopeEntity();
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scope);
+
+        $grant = new AuthCodeGrant(
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+
+        $server = new AuthorizationServer(
+            $clientRepositoryMock,
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $scopeRepositoryMock,
+            'file://' . __DIR__ . '/Stubs/private.key',
+            'file://' . __DIR__ . '/Stubs/public.key'
+        );
+
+        $server->setDefaultScope(self::DEFAULT_SCOPE);
+        $server->enableGrantType($grant);
+
+        $request = new ServerRequest(
+            [],
+            [],
+            null,
+            null,
+            'php://input',
+            $headers = [],
+            $cookies = [],
+            $queryParams = [
+                'response_type' => 'code',
+                'client_id'     => 'foo',
+            ]
+        );
+
+        $this->assertInstanceOf(AuthorizationRequest::class, $server->validateAuthorizationRequest($request));
+    }
+
+    public function testValidateAuthorizationRequestWithMissingRedirectUri()
    {
        $client = new ClientEntity();
        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
@@ -168,7 +226,12 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
            ]
        );

-        $this->assertTrue($server->validateAuthorizationRequest($request) instanceof AuthorizationRequest);
+        try {
+            $server->validateAuthorizationRequest($request);
+        } catch (OAuthServerException $e) {
+            $this->assertEquals('invalid_client', $e->getErrorType());
+            $this->assertEquals(401, $e->getHttpStatusCode());
+        }
    }

    /**
@@ -178,9 +241,9 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
    public function testValidateAuthorizationRequestUnregistered()
    {
        $server = new AuthorizationServer(
-            $this->getMock(ClientRepositoryInterface::class),
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(ClientRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
            'file://' . __DIR__ . '/Stubs/private.key',
            'file://' . __DIR__ . '/Stubs/public.key'
        );
--- a/tests/CryptKeyTest.php
+++ b/tests/CryptKeyTest.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace LeagueTests\Utils;
+
+use League\OAuth2\Server\CryptKey;
+use PHPUnit\Framework\TestCase;
+
+class CryptKeyTest extends TestCase
+{
+    /**
+     * @expectedException \LogicException
+     */
+    public function testNoFile()
+    {
+        new CryptKey('undefined file');
+    }
+
+    public function testKeyCreation()
+    {
+        $keyFile = __DIR__ . '/Stubs/public.key';
+        $key = new CryptKey($keyFile, 'secret');
+
+        $this->assertEquals('file://' . $keyFile, $key->getKeyPath());
+        $this->assertEquals('secret', $key->getPassPhrase());
+    }
+
+    public function testKeyFileCreation()
+    {
+        $keyContent = file_get_contents(__DIR__ . '/Stubs/public.key');
+        $key = new CryptKey($keyContent);
+
+        $this->assertEquals(
+            'file://' . sys_get_temp_dir() . '/' . sha1($keyContent) . '.key',
+            $key->getKeyPath()
+        );
+    }
+}
--- a/tests/CryptTraitTest.php
+++ b/tests/CryptTraitTest.php
@@ -2,13 +2,13 @@

 namespace LeagueTests\Utils;

-use League\OAuth2\Server\CryptKey;
 use LeagueTests\Stubs\CryptTraitStub;
+use PHPUnit\Framework\TestCase;

-class CryptTraitTest extends \PHPUnit_Framework_TestCase
+class CryptTraitTest extends TestCase
 {
    /**
-     * CryptTrait stub
+     * @var \LeagueTests\Stubs\CryptTraitStub
     */
    protected $cryptStub;

@@ -26,30 +26,4 @@ class CryptTraitTest extends \PHPUnit_Framework_TestCase
        $this->assertNotEquals($payload, $encrypted);
        $this->assertEquals($payload, $plainText);
    }
-
-    /**
-     * @expectedException \LogicException
-     */
-    public function testBadPrivateKey()
-    {
-        $this->cryptStub->setPrivateKey(new CryptKey(__DIR__ . '/Stubs/public.key'));
-        $this->cryptStub->doEncrypt('');
-    }
-
-    /**
-     * @expectedException \LogicException
-     */
-    public function testBadPublicKey()
-    {
-        $this->cryptStub->setPublicKey(new CryptKey(__DIR__ . '/Stubs/private.key'));
-        $this->cryptStub->doDecrypt('');
-    }
-
-    /**
-     * @expectedException \LogicException
-     */
-    public function testNonExistentKey()
-    {
-        new CryptKey('foo/bar');
-    }
 }
--- a/tests/Grant/AbstractGrantTest.php
+++ b/tests/Grant/AbstractGrantTest.php
@@ -3,7 +3,6 @@
 namespace LeagueTests\Grant;

 use League\Event\Emitter;
-use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\AuthCodeEntityInterface;
 use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
@@ -19,19 +18,88 @@ use LeagueTests\Stubs\AuthCodeEntity;
 use LeagueTests\Stubs\ClientEntity;
 use LeagueTests\Stubs\RefreshTokenEntity;
 use LeagueTests\Stubs\ScopeEntity;
+use PHPUnit\Framework\TestCase;
 use Zend\Diactoros\ServerRequest;

-class AbstractGrantTest extends \PHPUnit_Framework_TestCase
+class AbstractGrantTest extends TestCase
 {
    public function testGetSet()
    {
        /** @var AbstractGrant $grantMock */
        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
-        $grantMock->setPrivateKey(new CryptKey(__DIR__ . '/../Stubs/private.key'));
-        $grantMock->setPublicKey(new CryptKey(__DIR__ . '/../Stubs/public.key'));
        $grantMock->setEmitter(new Emitter());
    }

+    public function testHttpBasicWithPassword()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Basic ' . base64_encode('Open:Sesame'));
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame(['Open', 'Sesame'], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
+    public function testHttpBasicNoPassword()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Basic ' . base64_encode('Open:'));
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame(['Open', ''], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
+    public function testHttpBasicNotBasic()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Foo ' . base64_encode('Open:Sesame'));
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame([null, null], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
+    public function testHttpBasicNotBase64()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Basic ||');
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame([null, null], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
+    public function testHttpBasicNoColon()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Basic ' . base64_encode('OpenSesame'));
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame([null, null], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
    public function testValidateClientPublic()
    {
        $client = new ClientEntity();
@@ -256,7 +324,7 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase

    public function testIssueRefreshToken()
    {
-        $refreshTokenRepoMock = $this->getMock(RefreshTokenRepositoryInterface::class);
+        $refreshTokenRepoMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
        $refreshTokenRepoMock
            ->expects($this->once())
            ->method('getNewRefreshToken')
@@ -274,14 +342,13 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
        $accessToken = new AccessTokenEntity();
        /** @var RefreshTokenEntityInterface $refreshToken */
        $refreshToken = $issueRefreshTokenMethod->invoke($grantMock, $accessToken);
-        $this->assertTrue($refreshToken instanceof RefreshTokenEntityInterface);
-        $this->assertFalse($refreshToken->isExpired());
+        $this->assertInstanceOf(RefreshTokenEntityInterface::class, $refreshToken);
        $this->assertEquals($accessToken, $refreshToken->getAccessToken());
    }

    public function testIssueAccessToken()
    {
-        $accessTokenRepoMock = $this->getMock(AccessTokenRepositoryInterface::class);
+        $accessTokenRepoMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
        $accessTokenRepoMock->method('getNewToken')->willReturn(new AccessTokenEntity());

        /** @var AbstractGrant $grantMock */
@@ -300,13 +367,12 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
            123,
            [new ScopeEntity()]
        );
-        $this->assertTrue($accessToken instanceof AccessTokenEntityInterface);
-        $this->assertFalse($accessToken->isExpired());
+        $this->assertInstanceOf(AccessTokenEntityInterface::class, $accessToken);
    }

    public function testIssueAuthCode()
    {
-        $authCodeRepoMock = $this->getMock(AuthCodeRepositoryInterface::class);
+        $authCodeRepoMock = $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock();
        $authCodeRepoMock->expects($this->once())->method('getNewAuthCode')->willReturn(new AuthCodeEntity());

        /** @var AbstractGrant $grantMock */
@@ -317,7 +383,8 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
        $issueAuthCodeMethod = $abstractGrantReflection->getMethod('issueAuthCode');
        $issueAuthCodeMethod->setAccessible(true);

-        $this->assertTrue(
+        $this->assertInstanceOf(
+            AuthCodeEntityInterface::class,
            $issueAuthCodeMethod->invoke(
                $grantMock,
                new \DateInterval('PT1H'),
@@ -325,7 +392,7 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
                123,
                'http://foo/bar',
                [new ScopeEntity()]
-            ) instanceof AuthCodeEntityInterface
+            )
        );
    }

@@ -401,7 +468,7 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
        $method = $abstractGrantReflection->getMethod('generateUniqueIdentifier');
        $method->setAccessible(true);

-        $this->assertTrue(is_string($method->invoke($grantMock)));
+        $this->assertInternalType('string', $method->invoke($grantMock));
    }

    public function testCanRespondToAuthorizationRequest()
--- a/tests/Grant/AuthCodeGrantTest.php
+++ b/tests/Grant/AuthCodeGrantTest.php
--- a/tests/Grant/ClientCredentialsGrantTest.php
+++ b/tests/Grant/ClientCredentialsGrantTest.php
@@ -9,11 +9,15 @@ use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
 use League\OAuth2\Server\Repositories\ScopeRepositoryInterface;
 use LeagueTests\Stubs\AccessTokenEntity;
 use LeagueTests\Stubs\ClientEntity;
+use LeagueTests\Stubs\ScopeEntity;
 use LeagueTests\Stubs\StubResponseType;
+use PHPUnit\Framework\TestCase;
 use Zend\Diactoros\ServerRequest;

-class ClientCredentialsGrantTest extends \PHPUnit_Framework_TestCase
+class ClientCredentialsGrantTest extends TestCase
 {
+    const DEFAULT_SCOPE = 'basic';
+
    public function testGetIdentifier()
    {
        $grant = new ClientCredentialsGrant();
@@ -30,7 +34,48 @@ class ClientCredentialsGrantTest extends \PHPUnit_Framework_TestCase
        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
        $accessTokenRepositoryMock->method('persistNewAccessToken')->willReturnSelf();

+        $scope = new ScopeEntity();
        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scope);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
+        $grant = new ClientCredentialsGrant();
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withParsedBody(
+            [
+                'client_id'     => 'foo',
+                'client_secret' => 'bar',
+            ]
+        );
+
+        $responseType = new StubResponseType();
+        $grant->respondToAccessTokenRequest($serverRequest, $responseType, new \DateInterval('PT5M'));
+
+        $this->assertInstanceOf(AccessTokenEntityInterface::class, $responseType->getAccessToken());
+    }
+
+    /**
+     * @expectedException     \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 5
+     */
+    public function testRespondToRequestFailsWithoutScope()
+    {
+        $client = new ClientEntity();
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willReturnSelf();
+
+        $scope = new ScopeEntity();
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scope);
        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);

        $grant = new ClientCredentialsGrant();
@@ -48,7 +93,5 @@ class ClientCredentialsGrantTest extends \PHPUnit_Framework_TestCase

        $responseType = new StubResponseType();
        $grant->respondToAccessTokenRequest($serverRequest, $responseType, new \DateInterval('PT5M'));
-
-        $this->assertTrue($responseType->getAccessToken() instanceof AccessTokenEntityInterface);
    }
 }
--- a/tests/Grant/ImplicitGrantTest.php
+++ b/tests/Grant/ImplicitGrantTest.php
@@ -3,20 +3,28 @@
 namespace LeagueTests\Grant;

 use League\OAuth2\Server\CryptKey;
+use League\OAuth2\Server\Exception\OAuthServerException;
+use League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException;
 use League\OAuth2\Server\Grant\ImplicitGrant;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
+use League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface;
+use League\OAuth2\Server\Repositories\ScopeRepositoryInterface;
 use League\OAuth2\Server\RequestTypes\AuthorizationRequest;
 use League\OAuth2\Server\ResponseTypes\RedirectResponse;
 use LeagueTests\Stubs\AccessTokenEntity;
 use LeagueTests\Stubs\ClientEntity;
 use LeagueTests\Stubs\CryptTraitStub;
+use LeagueTests\Stubs\ScopeEntity;
 use LeagueTests\Stubs\StubResponseType;
 use LeagueTests\Stubs\UserEntity;
+use PHPUnit\Framework\TestCase;
 use Zend\Diactoros\ServerRequest;

-class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
+class ImplicitGrantTest extends TestCase
 {
+    const DEFAULT_SCOPE = 'basic';
+
    /**
     * CryptTrait stub
     */
@@ -83,8 +91,15 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
        $clientRepositoryMock->method('getClientEntity')->willReturn($client);

+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeEntity = new ScopeEntity();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $request = new ServerRequest(
            [],
@@ -101,7 +116,7 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
            ]
        );

-        $this->assertTrue($grant->validateAuthorizationRequest($request) instanceof AuthorizationRequest);
+        $this->assertInstanceOf(AuthorizationRequest::class, $grant->validateAuthorizationRequest($request));
    }

    public function testValidateAuthorizationRequestRedirectUriArray()
@@ -111,8 +126,15 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
        $clientRepositoryMock->method('getClientEntity')->willReturn($client);

+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeEntity = new ScopeEntity();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $request = new ServerRequest(
            [],
@@ -129,7 +151,7 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
            ]
        );

-        $this->assertTrue($grant->validateAuthorizationRequest($request) instanceof AuthorizationRequest);
+        $this->assertInstanceOf(AuthorizationRequest::class, $grant->validateAuthorizationRequest($request));
    }

    /**
@@ -266,10 +288,9 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase

        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);

-        $this->assertTrue($grant->completeAuthorizationRequest($authRequest) instanceof RedirectResponse);
+        $this->assertInstanceOf(RedirectResponse::class, $grant->completeAuthorizationRequest($authRequest));
    }

    /**
@@ -290,9 +311,143 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase

        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);

        $grant->completeAuthorizationRequest($authRequest);
    }
+
+    public function testAccessTokenRepositoryUniqueConstraintCheck()
+    {
+        $authRequest = new AuthorizationRequest();
+        $authRequest->setAuthorizationApproved(true);
+        $authRequest->setClient(new ClientEntity());
+        $authRequest->setGrantTypeId('authorization_code');
+        $authRequest->setUser(new UserEntity());
+
+        /** @var AccessTokenRepositoryInterface|\PHPUnit_Framework_MockObject_MockObject $accessTokenRepositoryMock */
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->expects($this->at(0))->method('persistNewAccessToken')->willThrowException(UniqueTokenIdentifierConstraintViolationException::create());
+        $accessTokenRepositoryMock->expects($this->at(1))->method('persistNewAccessToken')->willReturnSelf();
+
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+
+        $this->assertInstanceOf(RedirectResponse::class, $grant->completeAuthorizationRequest($authRequest));
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 7
+     */
+    public function testAccessTokenRepositoryFailToPersist()
+    {
+        $authRequest = new AuthorizationRequest();
+        $authRequest->setAuthorizationApproved(true);
+        $authRequest->setClient(new ClientEntity());
+        $authRequest->setGrantTypeId('authorization_code');
+        $authRequest->setUser(new UserEntity());
+
+        /** @var AccessTokenRepositoryInterface|\PHPUnit_Framework_MockObject_MockObject $accessTokenRepositoryMock */
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willThrowException(OAuthServerException::serverError('something bad happened'));
+
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+
+        $grant->completeAuthorizationRequest($authRequest);
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException
+     * @expectedExceptionCode 100
+     */
+    public function testAccessTokenRepositoryFailToPersistUniqueNoInfiniteLoop()
+    {
+        $authRequest = new AuthorizationRequest();
+        $authRequest->setAuthorizationApproved(true);
+        $authRequest->setClient(new ClientEntity());
+        $authRequest->setGrantTypeId('authorization_code');
+        $authRequest->setUser(new UserEntity());
+
+        /** @var AccessTokenRepositoryInterface|\PHPUnit_Framework_MockObject_MockObject $accessTokenRepositoryMock */
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willThrowException(UniqueTokenIdentifierConstraintViolationException::create());
+
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+
+        $grant->completeAuthorizationRequest($authRequest);
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testSetRefreshTokenTTL()
+    {
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->setRefreshTokenTTL(new \DateInterval('PT10M'));
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testSetRefreshTokenRepository()
+    {
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
+        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testCompleteAuthorizationRequestNoUser()
+    {
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->completeAuthorizationRequest(new AuthorizationRequest());
+    }
+
+    /**
+     * @expectedException     \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 5
+     */
+    public function testValidateAuthorizationRequestFailsWithoutScope()
+    {
+        $client = new ClientEntity();
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeEntity = new ScopeEntity();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+
+        $request = new ServerRequest(
+            [],
+            [],
+            null,
+            null,
+            'php://input',
+            $headers = [],
+            $cookies = [],
+            $queryParams = [
+                'response_type' => 'code',
+                'client_id'     => 'foo',
+                'redirect_uri'  => 'http://foo/bar',
+            ]
+        );
+
+        $grant->validateAuthorizationRequest($request);
+    }
 }
--- a/tests/Grant/PasswordGrantTest.php
+++ b/tests/Grant/PasswordGrantTest.php
@@ -13,16 +13,20 @@ use League\OAuth2\Server\Repositories\UserRepositoryInterface;
 use LeagueTests\Stubs\AccessTokenEntity;
 use LeagueTests\Stubs\ClientEntity;
 use LeagueTests\Stubs\RefreshTokenEntity;
+use LeagueTests\Stubs\ScopeEntity;
 use LeagueTests\Stubs\StubResponseType;
 use LeagueTests\Stubs\UserEntity;
+use PHPUnit\Framework\TestCase;
 use Zend\Diactoros\ServerRequest;

-class PasswordGrantTest extends \PHPUnit_Framework_TestCase
+class PasswordGrantTest extends TestCase
 {
+    const DEFAULT_SCOPE = 'basic';
+
    public function testGetIdentifier()
    {
-        $userRepositoryMock = $this->getMock(UserRepositoryInterface::class);
-        $refreshTokenRepositoryMock = $this->getMock(RefreshTokenRepositoryInterface::class);
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();

        $grant = new PasswordGrant($userRepositoryMock, $refreshTokenRepositoryMock);
        $this->assertEquals('password', $grant->getIdentifier());
@@ -46,13 +50,16 @@ class PasswordGrantTest extends \PHPUnit_Framework_TestCase
        $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willReturnSelf();
        $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());

+        $scope = new ScopeEntity();
        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scope);
        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);

        $grant = new PasswordGrant($userRepositoryMock, $refreshTokenRepositoryMock);
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $serverRequest = new ServerRequest();
        $serverRequest = $serverRequest->withParsedBody(
@@ -67,8 +74,8 @@ class PasswordGrantTest extends \PHPUnit_Framework_TestCase
        $responseType = new StubResponseType();
        $grant->respondToAccessTokenRequest($serverRequest, $responseType, new \DateInterval('PT5M'));

-        $this->assertTrue($responseType->getAccessToken() instanceof AccessTokenEntityInterface);
-        $this->assertTrue($responseType->getRefreshToken() instanceof RefreshTokenEntityInterface);
+        $this->assertInstanceOf(AccessTokenEntityInterface::class, $responseType->getAccessToken());
+        $this->assertInstanceOf(RefreshTokenEntityInterface::class, $responseType->getRefreshToken());
    }

    /**
@@ -167,4 +174,50 @@ class PasswordGrantTest extends \PHPUnit_Framework_TestCase
        $responseType = new StubResponseType();
        $grant->respondToAccessTokenRequest($serverRequest, $responseType, new \DateInterval('PT5M'));
    }
+
+    /**
+     * @expectedException     \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 5
+     */
+    public function testRespondToRequestFailsWithoutScope()
+    {
+        $client = new ClientEntity();
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willReturnSelf();
+
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $userEntity = new UserEntity();
+        $userRepositoryMock->method('getUserEntityByUserCredentials')->willReturn($userEntity);
+
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
+        $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willReturnSelf();
+        $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
+
+        $scope = new ScopeEntity();
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scope);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
+        $grant = new PasswordGrant($userRepositoryMock, $refreshTokenRepositoryMock);
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withParsedBody(
+            [
+                'client_id'     => 'foo',
+                'client_secret' => 'bar',
+                'username'      => 'foo',
+                'password'      => 'bar',
+            ]
+        );
+
+        $responseType = new StubResponseType();
+        $grant->respondToAccessTokenRequest($serverRequest, $responseType, new \DateInterval('PT5M'));
+    }
 }
--- a/tests/Grant/RefreshTokenGrantTest.php
+++ b/tests/Grant/RefreshTokenGrantTest.php
@@ -16,12 +16,13 @@ use LeagueTests\Stubs\CryptTraitStub;
 use LeagueTests\Stubs\RefreshTokenEntity;
 use LeagueTests\Stubs\ScopeEntity;
 use LeagueTests\Stubs\StubResponseType;
+use PHPUnit\Framework\TestCase;
 use Zend\Diactoros\ServerRequest;

-class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
+class RefreshTokenGrantTest extends TestCase
 {
    /**
-     * CryptTrait stub
+     * @var CryptTraitStub
     */
    protected $cryptStub;

@@ -32,7 +33,7 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase

    public function testGetIdentifier()
    {
-        $refreshTokenRepositoryMock = $this->getMock(RefreshTokenRepositoryInterface::class);
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();

        $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
        $this->assertEquals('refresh_token', $grant->getIdentifier());
@@ -45,27 +46,24 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
        $clientRepositoryMock->method('getClientEntity')->willReturn($client);

-        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
        $scopeEntity = new ScopeEntity();
+        $scopeEntity->setIdentifier('foo');
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);

        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
-        $accessTokenRepositoryMock
-            ->expects($this->once())
-            ->method('persistNewAccessToken')->willReturnSelf();
+        $accessTokenRepositoryMock->expects($this->once())->method('persistNewAccessToken')->willReturnSelf();

        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
        $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
-        $refreshTokenRepositoryMock
-            ->expects($this->once())
-            ->method('persistNewRefreshToken')->willReturnSelf();
+        $refreshTokenRepositoryMock->expects($this->once())->method('persistNewRefreshToken')->willReturnSelf();

        $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setScopeRepository($scopeRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));

        $oldRefreshToken = $this->cryptStub->doEncrypt(
@@ -82,19 +80,18 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        );

        $serverRequest = new ServerRequest();
-        $serverRequest = $serverRequest->withParsedBody(
-            [
-                'client_id'     => 'foo',
-                'client_secret' => 'bar',
-                'refresh_token' => $oldRefreshToken,
-            ]
-        );
+        $serverRequest = $serverRequest->withParsedBody([
+            'client_id'     => 'foo',
+            'client_secret' => 'bar',
+            'refresh_token' => $oldRefreshToken,
+            'scopes'        => ['foo'],
+        ]);

        $responseType = new StubResponseType();
        $grant->respondToAccessTokenRequest($serverRequest, $responseType, new \DateInterval('PT5M'));

-        $this->assertTrue($responseType->getAccessToken() instanceof AccessTokenEntityInterface);
-        $this->assertTrue($responseType->getRefreshToken() instanceof RefreshTokenEntityInterface);
+        $this->assertInstanceOf(AccessTokenEntityInterface::class, $responseType->getAccessToken());
+        $this->assertInstanceOf(RefreshTokenEntityInterface::class, $responseType->getRefreshToken());
    }

    public function testRespondToReducedScopes()
@@ -121,7 +118,7 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));

        $oldRefreshToken = $this->cryptStub->doEncrypt(
@@ -150,8 +147,8 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        $responseType = new StubResponseType();
        $grant->respondToAccessTokenRequest($serverRequest, $responseType, new \DateInterval('PT5M'));

-        $this->assertTrue($responseType->getAccessToken() instanceof AccessTokenEntityInterface);
-        $this->assertTrue($responseType->getRefreshToken() instanceof RefreshTokenEntityInterface);
+        $this->assertInstanceOf(AccessTokenEntityInterface::class, $responseType->getAccessToken());
+        $this->assertInstanceOf(RefreshTokenEntityInterface::class, $responseType->getRefreshToken());
    }

    /**
@@ -180,7 +177,7 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));

        $oldRefreshToken = $this->cryptStub->doEncrypt(
@@ -227,7 +224,7 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));

        $serverRequest = new ServerRequest();
@@ -259,7 +256,7 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));

        $oldRefreshToken = 'foobar';
@@ -291,14 +288,13 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
        $accessTokenRepositoryMock->method('persistNewAccessToken')->willReturnSelf();

-
        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
        $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willReturnSelf();

        $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));

        $oldRefreshToken = $this->cryptStub->doEncrypt(
@@ -344,7 +340,7 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));

        $oldRefreshToken = $this->cryptStub->doEncrypt(
@@ -391,7 +387,7 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
        $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());
        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));

        $oldRefreshToken = $this->cryptStub->doEncrypt(
--- a/tests/Middleware/AuthorizationServerMiddlewareTest.php
+++ b/tests/Middleware/AuthorizationServerMiddlewareTest.php
@@ -11,21 +11,27 @@ use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
 use League\OAuth2\Server\Repositories\ScopeRepositoryInterface;
 use LeagueTests\Stubs\AccessTokenEntity;
 use LeagueTests\Stubs\ClientEntity;
+use LeagueTests\Stubs\ScopeEntity;
 use LeagueTests\Stubs\StubResponseType;
+use PHPUnit\Framework\TestCase;
 use Zend\Diactoros\Response;
 use Zend\Diactoros\ServerRequestFactory;

-class AuthorizationServerMiddlewareTest extends \PHPUnit_Framework_TestCase
+class AuthorizationServerMiddlewareTest extends TestCase
 {
+    const DEFAULT_SCOPE = 'basic';
+
    public function testValidResponse()
    {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
        $clientRepository->method('getClientEntity')->willReturn(new ClientEntity());

+        $scopeEntity = new ScopeEntity;
        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);
        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);

-        $accessRepositoryMock = $this->getMock(AccessTokenRepositoryInterface::class);
+        $accessRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
        $accessRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());

        $server = new AuthorizationServer(
@@ -33,10 +39,11 @@ class AuthorizationServerMiddlewareTest extends \PHPUnit_Framework_TestCase
            $accessRepositoryMock,
            $scopeRepositoryMock,
            'file://' . __DIR__ . '/../Stubs/private.key',
-            'file://' . __DIR__ . '/../Stubs/public.key',
+            base64_encode(random_bytes(36)),
            new StubResponseType()
        );

+        $server->setDefaultScope(self::DEFAULT_SCOPE);
        $server->enableGrantType(new ClientCredentialsGrant());

        $_POST['grant_type'] = 'client_credentials';
@@ -58,15 +65,15 @@ class AuthorizationServerMiddlewareTest extends \PHPUnit_Framework_TestCase

    public function testOAuthErrorResponse()
    {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
        $clientRepository->method('getClientEntity')->willReturn(null);

        $server = new AuthorizationServer(
            $clientRepository,
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
            'file://' . __DIR__ . '/../Stubs/private.key',
-            'file://' . __DIR__ . '/../Stubs/public.key',
+            base64_encode(random_bytes(36)),
            new StubResponseType()
        );

@@ -97,7 +104,8 @@ class AuthorizationServerMiddlewareTest extends \PHPUnit_Framework_TestCase
        $response = $exception->generateHttpResponse(new Response());

        $this->assertEquals(302, $response->getStatusCode());
-        $this->assertEquals('http://foo/bar?error=invalid_scope&message=The+requested+scope+is+invalid%2C+unknown%2C+or+malformed&hint=Check+the+%60test%60+scope', $response->getHeader('location')[0]);
+        $this->assertEquals('http://foo/bar?error=invalid_scope&message=The+requested+scope+is+invalid%2C+unknown%2C+or+malformed&hint=Check+the+%60test%60+scope',
+            $response->getHeader('location')[0]);
    }

    public function testOAuthErrorResponseRedirectUriFragment()
@@ -106,6 +114,7 @@ class AuthorizationServerMiddlewareTest extends \PHPUnit_Framework_TestCase
        $response = $exception->generateHttpResponse(new Response(), true);

        $this->assertEquals(302, $response->getStatusCode());
-        $this->assertEquals('http://foo/bar#error=invalid_scope&message=The+requested+scope+is+invalid%2C+unknown%2C+or+malformed&hint=Check+the+%60test%60+scope', $response->getHeader('location')[0]);
+        $this->assertEquals('http://foo/bar#error=invalid_scope&message=The+requested+scope+is+invalid%2C+unknown%2C+or+malformed&hint=Check+the+%60test%60+scope',
+            $response->getHeader('location')[0]);
    }
 }
--- a/tests/Middleware/ResourceServerMiddlewareTest.php
+++ b/tests/Middleware/ResourceServerMiddlewareTest.php
@@ -8,15 +8,16 @@ use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\ResourceServer;
 use LeagueTests\Stubs\AccessTokenEntity;
 use LeagueTests\Stubs\ClientEntity;
+use PHPUnit\Framework\TestCase;
 use Zend\Diactoros\Response;
 use Zend\Diactoros\ServerRequest;

-class ResourceServerMiddlewareTest extends \PHPUnit_Framework_TestCase
+class ResourceServerMiddlewareTest extends TestCase
 {
    public function testValidResponse()
    {
        $server = new ResourceServer(
-            $this->getMock(AccessTokenRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
            'file://' . __DIR__ . '/../Stubs/public.key'
        );

@@ -51,7 +52,7 @@ class ResourceServerMiddlewareTest extends \PHPUnit_Framework_TestCase
    public function testValidResponseExpiredToken()
    {
        $server = new ResourceServer(
-            $this->getMock(AccessTokenRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
            'file://' . __DIR__ . '/../Stubs/public.key'
        );

@@ -86,7 +87,7 @@ class ResourceServerMiddlewareTest extends \PHPUnit_Framework_TestCase
    public function testErrorResponse()
    {
        $server = new ResourceServer(
-            $this->getMock(AccessTokenRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
            'file://' . __DIR__ . '/../Stubs/public.key'
        );

--- a/tests/ResourceServerTest.php
+++ b/tests/ResourceServerTest.php
@@ -6,14 +6,15 @@ namespace LeagueTests;
 use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\ResourceServer;
+use PHPUnit\Framework\TestCase;
 use Zend\Diactoros\ServerRequestFactory;

-class ResourceServerTest extends \PHPUnit_Framework_TestCase
+class ResourceServerTest extends TestCase
 {
    public function testValidateAuthenticatedRequest()
    {
        $server = new ResourceServer(
-            $this->getMock(AccessTokenRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
            'file://' . __DIR__ . '/Stubs/public.key'
        );

--- a/tests/ResponseTypes/BearerResponseTypeTest.php
+++ b/tests/ResponseTypes/BearerResponseTypeTest.php
@@ -11,11 +11,12 @@ use LeagueTests\Stubs\AccessTokenEntity;
 use LeagueTests\Stubs\ClientEntity;
 use LeagueTests\Stubs\RefreshTokenEntity;
 use LeagueTests\Stubs\ScopeEntity;
+use PHPUnit\Framework\TestCase;
 use Psr\Http\Message\ResponseInterface;
 use Zend\Diactoros\Response;
 use Zend\Diactoros\ServerRequest;

-class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
+class BearerResponseTypeTest extends TestCase
 {
    public function testGenerateHttpResponse()
    {
@@ -23,7 +24,7 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase

        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $responseType->setEncryptionKey(base64_encode(random_bytes(36)));

        $client = new ClientEntity();
        $client->setIdentifier('clientName');
@@ -47,7 +48,7 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase

        $response = $responseType->generateHttpResponse(new Response());

-        $this->assertTrue($response instanceof ResponseInterface);
+        $this->assertInstanceOf(ResponseInterface::class, $response);
        $this->assertEquals(200, $response->getStatusCode());
        $this->assertEquals('no-cache', $response->getHeader('pragma')[0]);
        $this->assertEquals('no-store', $response->getHeader('cache-control')[0]);
@@ -55,10 +56,57 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase

        $response->getBody()->rewind();
        $json = json_decode($response->getBody()->getContents());
-        $this->assertEquals('Bearer', $json->token_type);
-        $this->assertTrue(isset($json->expires_in));
-        $this->assertTrue(isset($json->access_token));
-        $this->assertTrue(isset($json->refresh_token));
+        $this->assertAttributeEquals('Bearer', 'token_type', $json);
+        $this->assertObjectHasAttribute('expires_in', $json);
+        $this->assertObjectHasAttribute('access_token', $json);
+        $this->assertObjectHasAttribute('refresh_token', $json);
+    }
+
+    public function testGenerateHttpResponseWithExtraParams()
+    {
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+
+        $responseType = new BearerTokenResponseWithParams($accessTokenRepositoryMock);
+        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $responseType->setEncryptionKey(base64_encode(random_bytes(36)));
+
+        $client = new ClientEntity();
+        $client->setIdentifier('clientName');
+
+        $scope = new ScopeEntity();
+        $scope->setIdentifier('basic');
+
+        $accessToken = new AccessTokenEntity();
+        $accessToken->setIdentifier('abcdef');
+        $accessToken->setExpiryDateTime((new \DateTime())->add(new \DateInterval('PT1H')));
+        $accessToken->setClient($client);
+        $accessToken->addScope($scope);
+
+        $refreshToken = new RefreshTokenEntity();
+        $refreshToken->setIdentifier('abcdef');
+        $refreshToken->setAccessToken($accessToken);
+        $refreshToken->setExpiryDateTime((new \DateTime())->add(new \DateInterval('PT1H')));
+
+        $responseType->setAccessToken($accessToken);
+        $responseType->setRefreshToken($refreshToken);
+
+        $response = $responseType->generateHttpResponse(new Response());
+
+        $this->assertInstanceOf(ResponseInterface::class, $response);
+        $this->assertEquals(200, $response->getStatusCode());
+        $this->assertEquals('no-cache', $response->getHeader('pragma')[0]);
+        $this->assertEquals('no-store', $response->getHeader('cache-control')[0]);
+        $this->assertEquals('application/json; charset=UTF-8', $response->getHeader('content-type')[0]);
+
+        $response->getBody()->rewind();
+        $json = json_decode($response->getBody()->getContents());
+        $this->assertAttributeEquals('Bearer', 'token_type', $json);
+        $this->assertObjectHasAttribute('expires_in', $json);
+        $this->assertObjectHasAttribute('access_token', $json);
+        $this->assertObjectHasAttribute('refresh_token', $json);
+
+        $this->assertObjectHasAttribute('foo', $json);
+        $this->assertAttributeEquals('bar', 'foo', $json);
    }

    public function testDetermineAccessTokenInHeaderValidToken()
@@ -68,7 +116,7 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase

        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $responseType->setEncryptionKey(base64_encode(random_bytes(36)));

        $client = new ClientEntity();
        $client->setIdentifier('clientName');
@@ -94,7 +142,6 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
        $accessTokenRepositoryMock->method('isAccessTokenRevoked')->willReturn(false);

        $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
-        $authorizationValidator->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));

        $request = new ServerRequest();
@@ -115,7 +162,7 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase

        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $responseType->setEncryptionKey(base64_encode(random_bytes(36)));

        $client = new ClientEntity();
        $client->setIdentifier('clientName');
@@ -138,7 +185,6 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
        $json = json_decode((string) $response->getBody());

        $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
-        $authorizationValidator->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));

        $request = new ServerRequest();
@@ -158,7 +204,7 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
    {
        $responseType = new BearerTokenResponse();
        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $responseType->setEncryptionKey(base64_encode(random_bytes(36)));

        $client = new ClientEntity();
        $client->setIdentifier('clientName');
@@ -184,7 +230,6 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
        $accessTokenRepositoryMock->method('isAccessTokenRevoked')->willReturn(true);

        $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
-        $authorizationValidator->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));

        $request = new ServerRequest();
@@ -206,12 +251,11 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase

        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $responseType->setEncryptionKey(base64_encode(random_bytes(36)));

        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();

        $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
-        $authorizationValidator->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));

        $request = new ServerRequest();
@@ -226,4 +270,30 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
            );
        }
    }
+
+    public function testDetermineMissingBearerInHeader()
+    {
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+
+        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
+        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $responseType->setEncryptionKey(base64_encode(random_bytes(36)));
+
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+
+        $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
+        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+
+        $request = new ServerRequest();
+        $request = $request->withHeader('authorization', 'Bearer blah.blah.blah');
+
+        try {
+            $authorizationValidator->validateAuthorization($request);
+        } catch (OAuthServerException $e) {
+            $this->assertEquals(
+                'Error while decoding to JSON',
+                $e->getHint()
+            );
+        }
+    }
 }
--- a/tests/ResponseTypes/BearerTokenResponseWithParams.php
+++ b/tests/ResponseTypes/BearerTokenResponseWithParams.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace LeagueTests\ResponseTypes;
+
+use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
+use League\OAuth2\Server\ResponseTypes\BearerTokenResponse;
+
+class BearerTokenResponseWithParams extends BearerTokenResponse
+{
+    protected function getExtraParams(AccessTokenEntityInterface $accessToken)
+    {
+        return ['foo' => 'bar', 'token_type' => 'Should not overwrite'];
+    }
+}
--- a/tests/Stubs/CryptTraitStub.php
+++ b/tests/Stubs/CryptTraitStub.php
@@ -2,7 +2,6 @@

 namespace LeagueTests\Stubs;

-use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\CryptTrait;

 class CryptTraitStub
@@ -11,8 +10,12 @@ class CryptTraitStub

    public function __construct()
    {
-        $this->setPrivateKey(new CryptKey('file://' . __DIR__ . '/private.key'));
-        $this->setPublicKey(new CryptKey('file://' . __DIR__ . '/public.key'));
+        $this->setEncryptionKey(base64_encode(random_bytes(36)));
+    }
+
+    public function getKey()
+    {
+        return $this->encryptionKey;
    }

    public function doEncrypt($unencryptedData)