Merge pull request #854 from Sephster/master

Version 7
Fix release tags in changelog
2025-05-31 14:12:07 +05:30 · 2018-02-18 15:57:10 +00:00 · 2018-02-18 15:51:41 +00:00 · 2018-02-18 15:38:28 +00:00 · 2018-02-18 15:33:41 +00:00 · 2018-02-18 15:29:59 +00:00
57 changed files with 1185 additions and 824 deletions
--- a/.gitattributes
+++ b/.gitattributes
@@ -10,4 +10,5 @@
 /phpunit.xml.dist export-ignore
 /CHANGELOG.md export-ignore
 /CONTRIBUTING.md export-ignore
-/README.md export-ignore
+/README.md export-ignore
+
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,24 +1,31 @@
 language: php

+dist: trusty
 sudo: false

 cache:
  directories:
-  - vendor
+    - vendor
+
+env:
+  - DEPENDENCIES=""
+  - DEPENDENCIES="--prefer-lowest --prefer-stable"

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

 install:
-  - travis_retry composer install --no-interaction --prefer-source
+  - composer update --no-interaction --prefer-dist $DEPENDENCIES

 script:
-  - vendor/bin/phpunit
+  - vendor/bin/phpunit --coverage-clover=coverage.clover
+  - vendor/bin/phpstan analyse -l 6 -c phpstan.neon src tests
+
+after_script:
+    - wget https://scrutinizer-ci.com/ocular.phar
+    - php ocular.phar code-coverage:upload --format=php-clover coverage.clover

 branches:
  only:
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,334 +1,423 @@
 # Changelog
+All notable changes to this project will be documented in this file.

-## 5.1.4 (released 2017-07-01)
+The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).

-* 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)
+## [Unreleased]

-## 5.1.3 (released 2016-10-12)
+## [7.0.0] - released 2018-02-17

-* Fixed WWW-Authenticate header (Issue #669)
-* Increase the recommended RSA key length from 1024 to 2048 bits (Issue #668)
+### Added
+- Use PHPStan for static analysis of code (PR #848)
+- Enforce stricter static analysis checks and upgrade library dependencies (PR #852)
+- Provide PHPStan coverage for tests and update PHPUnit (PR #849)
+- Get and set methods for OAuth Server Exception payloads. Allow implementer to specify the JSON encode options (PR #719)

-## 5.1.2 (released 2016-09-19)
+### Changed
+- ClientRepository interface will now accept null for the Grant type to improve extensibility options (PR #607)
+- Do not issue an error if key file permissions are 400 or 440 (PR #839)
+- Skip key file creation if the file already exists (PR #845)
+- Change changelog format and update readme

-* Fixed `finalizeScopes` call (Issue #650)
+### Removed
+- Support for PHP 5.6
+- Support for version 5.x and 6.x of the library

-## 5.1.1 (released 2016-07-26)
+### Fixed
+- PKCE implementation (PR #744)
+- Set correct redirect URI when validating scopes (PR #840)
+- S256 code challenege method (PR #842)
+- Accept RSA key with CRLF line endings (PR #805)

-* 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)
+## [6.1.1] - 2017-12-23

-## 5.1.0 (released 2016-06-28)
+- Removed check on empty scopes

-* 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
+## [6.1.0] - 2017-12-23

-## 5.0.3 (released 2016-05-04)
+- Changed the token type issued by the Implicit Grant to be Bearer instead of bearer. (PR #724)
+- Replaced call to array_key_exists() with the faster isset() on the Implicit Grant. (PR #749)
+- Allow specification of query delimiter character in the Password Grant (PR #801)
+- Add Zend Diactoros library dependency to examples (PR #678)
+- Can set default scope for the authorization endpoint. If no scope is passed during an authorization request, the default scope will be used if set. If not, the server will issue an invalid scope exception (PR #811)
+- Added validation for redirect URIs on the authorization end point to ensure exactly one redirection URI has been passed (PR #573)

-* Fix hints in PasswordGrant (Issue #560)
-* Add meaning of `Resource owner` to terminology.md (Issue #561)
-* Use constant for event name instead of explicit string (Issue #563)
-* Remove unused request property (Issue #564)
-* Correct wrong phpdoc (Issue #569)
-* Fixed typo in exception string (Issue #570)
+## [6.0.2] - 2017-08-03

-## 5.0.2 (released 2016-04-18)
+- 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)

-* `state` parameter is now correctly returned after implicit grant authorization
-* Small code and docblock improvements
+## [6.0.1] - 2017-07-19

-## 5.0.1 (released 2016-04-18)
+To address feedback from the security release the following change has been made:

-* Fixes an issue (#550) whereby it was unclear whether or not to validate a client's secret during a request.
+- If an RSA key cannot be chmod'ed to 600 then it will now throw a E_USER_NOTICE instead of an exception.

-## 5.0.0 (released 2016-04-17)
+## [6.0.0] - 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] - 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] - 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] - 2016-09-19
+
+- Fixed `finalizeScopes` call (Issue #650)
+
+## [5.1.1] - 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] - 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] - 2016-05-04
+
+- Fix hints in PasswordGrant (Issue #560)
+- Add meaning of `Resource owner` to terminology.md (Issue #561)
+- Use constant for event name instead of explicit string (Issue #563)
+- Remove unused request property (Issue #564)
+- Correct wrong phpdoc (Issue #569)
+- Fixed typo in exception string (Issue #570)
+
+## [5.0.2] - 2016-04-18
+
+- `state` parameter is now correctly returned after implicit grant authorization
+- Small code and docblock improvements
+
+## [5.0.1] - 2016-04-18
+
+- Fixes an issue (#550) whereby it was unclear whether or not to validate a client's secret during a request.
+
+## [5.0.0] - 2016-04-17

 Version 5 is a complete code rewrite.

-* JWT support
-* PSR-7 support
-* Improved exception errors
-* Replace all occurrences of the term "Storage" with "Repository"
-* Simplify repositories
-* Entities conform to interfaces and use traits
-* Auth code grant updated
-    * Allow support for public clients
-    * Add support for #439
-* Client credentials grant updated
-* Password grant updated
-    * Allow support for public clients
-* Refresh token grant updated
-* Implement Implicit grant
-* Bearer token output type
-* Remove MAC token output type
-* Authorization server rewrite
-* Resource server class moved to PSR-7 middleware
-* Tests
-* Much much better documentation
+- Renamed Server class to AuthorizationServer
+- Added ResourceServer class
+- Run unit tests again PHP 5.5.9 as it's the minimum supported version
+- Enable PHPUnit 5.0 support
+- Improved examples and documentation
+- Make it clearer that the implicit grant doesn't support refresh tokens
+- Improved refresh token validation errors
+- Fixed refresh token expiry date

-Changes since RC2:
+## [5.0.0-RC2] - 2016-04-10

-* Renamed Server class to AuthorizationServer
-* Added ResourceServer class
-* Run unit tests again PHP 5.5.9 as it's the minimum supported version
-* Enable PHPUnit 5.0 support
-* Improved examples and documentation
-* Make it clearer that the implicit grant doesn't support refresh tokens
-* Improved refresh token validation errors
-* Fixed refresh token expiry date
+- Allow multiple client redirect URIs (Issue #511)
+- Remove unused mac token interface (Issue #503)
+- Handle RSA key passphrase (Issue #502)
+- Remove access token repository from response types (Issue #501)
+- Remove unnecessary methods from entity interfaces (Issue #490)
+- Ensure incoming JWT hasn't expired (Issue #509)
+- Fix client identifier passed where user identifier is expected (Issue #498)
+- Removed built-in entities; added traits to for quick re-use (Issue #504)
+- Redirect uri is required only if the "redirect_uri" parameter was included in the authorization request (Issue #514)
+- Removed templating for auth code and implicit grants (Issue #499)

-## 5.0.0-RC2 (released 2016-04-10)
-
-Changes since RC1:
-
-* Allow multiple client redirect URIs (Issue #511)
-* Remove unused mac token interface (Issue #503)
-* Handle RSA key passphrase (Issue #502)
-* Remove access token repository from response types (Issue #501)
-* Remove unnecessary methods from entity interfaces (Issue #490)
-* Ensure incoming JWT hasn't expired (Issue #509)
-* Fix client identifier passed where user identifier is expected (Issue #498)
-* Removed built-in entities; added traits to for quick re-use (Issue #504)
-* Redirect uri is required only if the "redirect_uri" parameter was included in the authorization request (Issue #514)
-* Removed templating for auth code and implicit grants (Issue #499)
-
-## 5.0.0-RC1 (release 2016-03-24)
+## [5.0.0-RC1] - 2016-03-24

 Version 5 is a complete code rewrite.

-* JWT support
-* PSR-7 support
-* Improved exception errors
-* Replace all occurrences of the term "Storage" with "Repository"
-* Simplify repositories
-* Entities conform to interfaces and use traits
-* Auth code grant updated
-    * Allow support for public clients
-    * Add support for #439
-* Client credentials grant updated
-* Password grant updated
-    * Allow support for public clients
-* Refresh token grant updated
-* Implement Implicit grant
-* Bearer token output type
-* Remove MAC token output type
-* Authorization server rewrite
-* Resource server class moved to PSR-7 middleware
-* Tests
-* Much much better documentation
+- JWT support
+- PSR-7 support
+- Improved exception errors
+- Replace all occurrences of the term "Storage" with "Repository"
+- Simplify repositories
+- Entities conform to interfaces and use traits
+- Auth code grant updated
+  - Allow support for public clients
+  - Add support for #439
+- Client credentials grant updated
+- Password grant updated
+  - Allow support for public clients
+- Refresh token grant updated
+- Implement Implicit grant
+- Bearer token output type
+- Remove MAC token output type
+- Authorization server rewrite
+- Resource server class moved to PSR-7 middleware
+- Tests
+- Much much better documentation

-## 4.1.5 (released 2016-01-04)
+## [4.1.5] - 2016-01-04

-* Enable Symfony 3.0 support (#412)
+- Enable Symfony 3.0 support (#412)

-## 4.1.4 (released 2015-11-13)
+## [4.1.4] - 2015-11-13

-* Fix for determining access token in header (Issue #328)
-* Refresh tokens are now returned for MAC responses (Issue #356)
-* Added integration list to readme (Issue #341)
-* Expose parameter passed to exceptions (Issue #345)
-* Removed duplicate routing setup code (Issue #346)
-* Docs fix (Issues #347, #360, #380)
-* Examples fix (Issues #348, #358)
-* Fix typo in docblock (Issue #352)
-* Improved timeouts for MAC tokens (Issue #364)
-* `hash_hmac()` should output raw binary data, not hexits (Issue #370)
-* Improved regex for matching all Base64 characters (Issue #371)
-* Fix incorrect signature parameter (Issue #372)
-* AuthCodeGrant and RefreshTokenGrant don't require client_secret (Issue #377)
-* Added priority argument to event listener (Issue #388)
+- Fix for determining access token in header (Issue #328)
+- Refresh tokens are now returned for MAC responses (Issue #356)
+- Added integration list to readme (Issue #341)
+- Expose parameter passed to exceptions (Issue #345)
+- Removed duplicate routing setup code (Issue #346)
+- Docs fix (Issues #347, #360, #380)
+- Examples fix (Issues #348, #358)
+- Fix typo in docblock (Issue #352)
+- Improved timeouts for MAC tokens (Issue #364)
+- `hash_hmac()` should output raw binary data, not hexits (Issue #370)
+- Improved regex for matching all Base64 characters (Issue #371)
+- Fix incorrect signature parameter (Issue #372)
+- AuthCodeGrant and RefreshTokenGrant don't require client_secret (Issue #377)
+- Added priority argument to event listener (Issue #388)

-## 4.1.3 (released 2015-03-22)
+## [4.1.3] - 2015-03-22

-* Docblock, namespace and inconsistency fixes (Issue #303)
-* Docblock type fix (Issue #310)
-* Example bug fix (Issue #300)
-* Updated league/event to ~2.1 (Issue #311)
-* Fixed missing session scope (Issue #319)
-* Updated interface docs (Issue #323)
-* `.travis.yml` updates
+- Docblock, namespace and inconsistency fixes (Issue #303)
+- Docblock type fix (Issue #310)
+- Example bug fix (Issue #300)
+- Updated league/event to ~2.1 (Issue #311)
+- Fixed missing session scope (Issue #319)
+- Updated interface docs (Issue #323)
+- `.travis.yml` updates

-## 4.1.2 (released 2015-01-01)
+## [4.1.2] - 2015-01-01

-* Remove side-effects in hash_equals() implementation (Issue #290)
+- Remove side-effects in hash_equals() implementation (Issue #290)

-## 4.1.1 (released 2014-12-31)
+## [4.1.1] - 2014-12-31

-* Changed `symfony/http-foundation` dependency version to `~2.4` so package can be installed in Laravel `4.1.*`
+- Changed `symfony/http-foundation` dependency version to `~2.4` so package can be installed in Laravel `4.1.*`

-## 4.1.0 (released 2014-12-27)
+## [4.1.0] - 2014-12-27

-* Added MAC token support (Issue #158)
-* Fixed example init code (Issue #280)
-* Toggle refresh token rotation (Issue #286)
-* Docblock fixes
+- Added MAC token support (Issue #158)
+- Fixed example init code (Issue #280)
+- Toggle refresh token rotation (Issue #286)
+- Docblock fixes

-## 4.0.5 (released 2014-12-15)
+## [4.0.5] - 2014-12-15

-* Prevent duplicate session in auth code grant (Issue #282)
+- Prevent duplicate session in auth code grant (Issue #282)

-## 4.0.4 (released 2014-12-03)
+## [4.0.4] - 2014-12-03

-* Ensure refresh token hasn't expired (Issue #270)
+- Ensure refresh token hasn't expired (Issue #270)

-## 4.0.3 (released 2014-12-02)
+## [4.0.3] - 2014-12-02

-* Fix bad type hintings (Issue #267)
-* Do not forget to set the expire time (Issue #268)
+- Fix bad type hintings (Issue #267)
+- Do not forget to set the expire time (Issue #268)

-## 4.0.2 (released 2014-11-21)
+## [4.0.2] - 2014-11-21

-* Improved interfaces (Issue #255)
-* Learnt how to spell delimiter and so `getScopeDelimiter()` and `setScopeDelimiter()` methods have been renamed
-* Docblock improvements (Issue #254)
+- Improved interfaces (Issue #255)
+- Learnt how to spell delimiter and so `getScopeDelimiter()` and `setScopeDelimiter()` methods have been renamed
+- Docblock improvements (Issue #254)

-## 4.0.1 (released 2014-11-09)
+## [4.0.1] - 2014-11-09

-* Alias the master branch in composer.json (Issue #243)
-* Numerous PHP CodeSniffer fixes (Issue #244)
-* .travis.yml update (Issue #245)
-* The getAccessToken method should return an AccessTokenEntity object instead of a string in ResourceServer.php (#246)
+- Alias the master branch in composer.json (Issue #243)
+- Numerous PHP CodeSniffer fixes (Issue #244)
+- .travis.yml update (Issue #245)
+- The getAccessToken method should return an AccessTokenEntity object instead of a string in ResourceServer.php (#246)

-## 4.0.0 (released 2014-11-08)
+## [4.0.0] - 2014-11-08

-* Complete rewrite
-* Check out the documentation - [http://oauth2.thephpleague.com](http://oauth2.thephpleague.com)
+- Complete rewrite
+- Check out the documentation - [http://oauth2.thephpleague.com](http://oauth2.thephpleague.com)

-## 3.2.0 (released 2014-04-16)
+## [3.2.0] - 2014-04-16

-* Added the ability to change the algorithm that is used to generate the token strings (Issue #151)
+- Added the ability to change the algorithm that is used to generate the token strings (Issue #151)

-## 3.1.2 (released 2014-02-26)
+## [3.1.2] - 2014-02-26

-* Support Authorization being an environment variable. [See more](http://fortrabbit.com/docs/essentials/quirks-and-constraints#authorization-header)
+- Support Authorization being an environment variable. [See more](http://fortrabbit.com/docs/essentials/quirks-and-constraints#authorization-header)

-## 3.1.1 (released 2013-12-05)
+## [3.1.1] - 2013-12-05

-* Normalize headers when `getallheaders()` is available (Issues #108 and #114)
+- Normalize headers when `getallheaders()` is available (Issues #108 and #114)

-## 3.1.0 (released 2013-12-05)
+## [3.1.0] - 2013-12-05

-* No longer necessary to inject the authorisation server into a grant, the server will inject itself
-* Added test for 1419ba8cdcf18dd034c8db9f7de86a2594b68605
+- No longer necessary to inject the authorisation server into a grant, the server will inject itself
+- Added test for 1419ba8cdcf18dd034c8db9f7de86a2594b68605

-## 3.0.1 (released 2013-12-02)
+## [3.0.1] - 2013-12-02

-* Forgot to tell TravisCI from testing PHP 5.3
+- Forgot to tell TravisCI from testing PHP 5.3

-## 3.0.0 (released 2013-12-02)
+## [3.0.0] - 2013-12-02

-* Fixed spelling of Implicit grant class (Issue #84)
-* Travis CI now tests for PHP 5.5
-* Fixes for checking headers for resource server (Issues #79 and #)
-* The word "bearer" now has a capital "B" in JSON output to match OAuth 2.0 spec
-* All grants no longer remove old sessions by default
-* All grants now support custom access token TTL (Issue #92)
-* All methods which didn't before return a value now return `$this` to support method chaining
-* Removed the build in DB providers - these will be put in their own repos to remove baggage in the main repository
-* Removed support for PHP 5.3 because this library now uses traits and will use other modern PHP features going forward
-* Moved some grant related functions into a trait to reduce duplicate code
+- Fixed spelling of Implicit grant class (Issue #84)
+- Travis CI now tests for PHP 5.5
+- Fixes for checking headers for resource server (Issues #79 and #)
+- The word "bearer" now has a capital "B" in JSON output to match OAuth 2.0 spec
+- All grants no longer remove old sessions by default
+- All grants now support custom access token TTL (Issue #92)
+- All methods which didn't before return a value now return `$this` to support method chaining
+- Removed the build in DB providers - these will be put in their own repos to remove baggage in the main repository
+- Removed support for PHP 5.3 because this library now uses traits and will use other modern PHP features going forward
+- Moved some grant related functions into a trait to reduce duplicate code

-## 2.1.1 (released 2013-06-02)
+## [2.1.1] - 2013-06-02

-* Added conditional `isValid()` flag to check for Authorization header only (thanks @alexmcroberts)
-* Fixed semantic meaning of `requireScopeParam()` and `requireStateParam()` by changing their default value to true
-* Updated some duff docblocks
-* Corrected array key call in Resource.php (Issue #63)
+- Added conditional `isValid()` flag to check for Authorization header only (thanks @alexmcroberts)
+- Fixed semantic meaning of `requireScopeParam()` and `requireStateParam()` by changing their default value to true
+- Updated some duff docblocks
+- Corrected array key call in Resource.php (Issue #63)

-## 2.1 (released 2013-05-10)
+## [2.1.0] - 2013-05-10

-* Moved zetacomponents/database to "suggest" in composer.json. If you rely on this feature you now need to include " zetacomponents/database" into "require" key in your own composer.json. (Issue #51)
-* New method in Refresh grant called `rotateRefreshTokens()`. Pass in `true` to issue a new refresh token each time an access token is refreshed. This parameter needs to be set to true in order to request reduced scopes with the new access token. (Issue #47)
-* Rename `key` column in oauth_scopes table to `scope` as `key` is a reserved SQL word. (Issue #45)
-* The `scope` parameter is no longer required by default as per the RFC. (Issue #43)
-* You can now set multiple default scopes by passing an array into `setDefaultScope()`. (Issue #42)
-* The password and client credentials grants now allow for multiple sessions per user. (Issue #32)
-* Scopes associated to authorization codes are not held in their own table (Issue #44)
-* Database schema updates.
+- Moved zetacomponents/database to "suggest" in composer.json. If you rely on this feature you now need to include " zetacomponents/database" into "require" key in your own composer.json. (Issue #51)
+- New method in Refresh grant called `rotateRefreshTokens()`. Pass in `true` to issue a new refresh token each time an access token is refreshed. This parameter needs to be set to true in order to request reduced scopes with the new access token. (Issue #47)
+- Rename `key` column in oauth_scopes table to `scope` as `key` is a reserved SQL word. (Issue #45)
+- The `scope` parameter is no longer required by default as per the RFC. (Issue #43)
+- You can now set multiple default scopes by passing an array into `setDefaultScope()`. (Issue #42)
+- The password and client credentials grants now allow for multiple sessions per user. (Issue #32)
+- Scopes associated to authorization codes are not held in their own table (Issue #44)
+- Database schema updates.

-## 2.0.5 (released 2013-05-09)
+## [2.0.5] - 2013-05-09

-* Fixed `oauth_session_token_scopes` table primary key
-* Removed `DEFAULT ''` that has slipped into some tables
-* Fixed docblock for `SessionInterface::associateRefreshToken()`
+- Fixed `oauth_session_token_scopes` table primary key
+- Removed `DEFAULT ''` that has slipped into some tables
+- Fixed docblock for `SessionInterface::associateRefreshToken()`

-## 2.0.4 (released 2013-05-09)
+## [2.0.4] - 2013-05-09

-* Renamed primary key in oauth_client_endpoints table
-* Adding missing column to oauth_session_authcodes
-* SECURITY FIX: A refresh token should be bound to a client ID
+- Renamed primary key in oauth_client_endpoints table
+- Adding missing column to oauth_session_authcodes

-## 2.0.3 (released 2013-05-08)
+### Security
+- A refresh token should be bound to a client ID

-* Fixed a link to code in composer.json
+## [2.0.3] - 2013-05-08

-## 2.0.2 (released 2013-05-08)
+- Fixed a link to code in composer.json

-* Updated README with wiki guides
-* Removed `null` as default parameters in some methods in the storage interfaces
-* Fixed license copyright
+## [2.0.2] - 2013-05-08

-## 2.0.0 (released 2013-05-08)
+- Updated README with wiki guides
+- Removed `null` as default parameters in some methods in the storage interfaces
+- Fixed license copyright
+
+## [2.0.0] - 2013-05-08

 **If you're upgrading from v1.0.8 there are lots of breaking changes**

-* Rewrote the session storage interface from scratch so methods are more obvious
-* Included a PDO driver which implements the storage interfaces so the library is more "get up and go"
-* Further normalised the database structure so all sessions no longer contain infomation related to authorization grant (which may or may not be enabled)
-* A session can have multiple associated access tokens
-* Individual grants can have custom expire times for access tokens
-* Authorization codes now have a TTL of 10 minutes by default (can be manually set)
-* Refresh tokens now have a TTL of one week by default (can be manually set)
-* The client credentials grant will no longer gives out refresh tokens as per the specification
+- Rewrote the session storage interface from scratch so methods are more obvious
+- Included a PDO driver which implements the storage interfaces so the library is more "get up and go"
+- Further normalised the database structure so all sessions no longer contain infomation related to authorization grant (which may or may not be enabled)
+- A session can have multiple associated access tokens
+- Individual grants can have custom expire times for access tokens
+- Authorization codes now have a TTL of 10 minutes by default (can be manually set)
+- Refresh tokens now have a TTL of one week by default (can be manually set)
+- The client credentials grant will no longer gives out refresh tokens as per the specification

-## 1.0.8 (released 2013-03-18)
+## [1.0.8] - 2013-03-18

-* Fixed check for required state parameter
-* Fixed check that user's credentials are correct in Password grant
+- Fixed check for required state parameter
+- Fixed check that user's credentials are correct in Password grant

-## 1.0.7 (released 2013-03-04)
+## [1.0.7] - 2013-03-04

-* Added method `requireStateParam()`
-* Added method `requireScopeParam()`
+- Added method `requireStateParam()`
+- Added method `requireScopeParam()`

-## 1.0.6 (released 2013-02-22)
+## [1.0.6] - 2013-02-22

-* Added links to tutorials in the README
-* Added missing `state` parameter request to the `checkAuthoriseParams()` method.
+- Added links to tutorials in the README
+- Added missing `state` parameter request to the `checkAuthoriseParams()` method.

-## 1.0.5 (released 2013-02-21)
+## [1.0.5] - 2013-02-21

-* Fixed the SQL example for SessionInterface::getScopes()
+- Fixed the SQL example for SessionInterface::getScopes()

-## 1.0.3 (released 2013-02-20)
+## [1.0.3] - 2013-02-20

-* Changed all instances of the "authentication server" to "authorization server"
+- Changed all instances of the "authentication server" to "authorization server"

-## 1.0.2 (released 2013-02-20)
+## [1.0.2] - 2013-02-20

-* Fixed MySQL create table order
-* Fixed version number in composer.json
+- Fixed MySQL create table order
+- Fixed version number in composer.json

-## 1.0.1 (released 2013-02-19)
+## [1.0.1] - 2013-02-19

-* Updated AuthServer.php to use `self::getParam()`
+- Updated AuthServer.php to use `self::getParam()`

-## 1.0.0 (released 2013-02-15)
+## 1.0.0 - 2013-02-15

-* First major release
+- First major release
+
+[Unreleased]: https://github.com/thephpleague/oauth2-server/compare/7.0.0...HEAD
+[7.0.0]: https://github.com/thephpleague/oauth2-server/compare/6.1.1...7.0.0
+[6.1.1]: https://github.com/thephpleague/oauth2-server/compare/6.0.0...6.1.1
+[6.1.0]: https://github.com/thephpleague/oauth2-server/compare/6.0.2...6.1.0
+[6.0.2]: https://github.com/thephpleague/oauth2-server/compare/6.0.1...6.0.2
+[6.0.1]: https://github.com/thephpleague/oauth2-server/compare/6.0.0...6.0.1
+[6.0.0]: https://github.com/thephpleague/oauth2-server/compare/5.1.4...6.0.0
+[5.1.4]: https://github.com/thephpleague/oauth2-server/compare/5.1.3...5.1.4
+[5.1.3]: https://github.com/thephpleague/oauth2-server/compare/5.1.2...5.1.3
+[5.1.2]: https://github.com/thephpleague/oauth2-server/compare/5.1.1...5.1.2
+[5.1.1]: https://github.com/thephpleague/oauth2-server/compare/5.1.0...5.1.1
+[5.1.0]: https://github.com/thephpleague/oauth2-server/compare/5.0.2...5.1.0
+[5.0.3]: https://github.com/thephpleague/oauth2-server/compare/5.0.3...5.0.2
+[5.0.2]: https://github.com/thephpleague/oauth2-server/compare/5.0.1...5.0.2
+[5.0.1]: https://github.com/thephpleague/oauth2-server/compare/5.0.0...5.0.1
+[5.0.0]: https://github.com/thephpleague/oauth2-server/compare/5.0.0-RC2...5.0.0
+[5.0.0-RC2]: https://github.com/thephpleague/oauth2-server/compare/5.0.0-RC1...5.0.0-RC2
+[5.0.0-RC1]: https://github.com/thephpleague/oauth2-server/compare/4.1.5...5.0.0-RC1
+[4.1.5]: https://github.com/thephpleague/oauth2-server/compare/4.1.4...4.1.5
+[4.1.4]: https://github.com/thephpleague/oauth2-server/compare/4.1.3...4.1.4
+[4.1.3]: https://github.com/thephpleague/oauth2-server/compare/4.1.2...4.1.3
+[4.1.2]: https://github.com/thephpleague/oauth2-server/compare/4.1.1...4.1.2
+[4.1.1]: https://github.com/thephpleague/oauth2-server/compare/4.0.0...4.1.1
+[4.1.0]: https://github.com/thephpleague/oauth2-server/compare/4.0.5...4.1.0
+[4.0.5]: https://github.com/thephpleague/oauth2-server/compare/4.0.4...4.0.5
+[4.0.4]: https://github.com/thephpleague/oauth2-server/compare/4.0.3...4.0.4
+[4.0.3]: https://github.com/thephpleague/oauth2-server/compare/4.0.2...4.0.3
+[4.0.2]: https://github.com/thephpleague/oauth2-server/compare/4.0.1...4.0.2
+[4.0.1]: https://github.com/thephpleague/oauth2-server/compare/4.0.0...4.0.1
+[4.0.0]: https://github.com/thephpleague/oauth2-server/compare/3.2.0...4.0.0
+[3.2.0]: https://github.com/thephpleague/oauth2-server/compare/3.1.2...3.2.0
+[3.1.2]: https://github.com/thephpleague/oauth2-server/compare/3.1.1...3.1.2
+[3.1.1]: https://github.com/thephpleague/oauth2-server/compare/3.1.0...3.1.1
+[3.1.0]: https://github.com/thephpleague/oauth2-server/compare/3.0.1...3.1.0
+[3.0.1]: https://github.com/thephpleague/oauth2-server/compare/3.0.0...3.0.1
+[3.0.0]: https://github.com/thephpleague/oauth2-server/compare/2.1.1...3.0.0
+[2.1.1]: https://github.com/thephpleague/oauth2-server/compare/2.1.0...2.1.1
+[2.1.0]: https://github.com/thephpleague/oauth2-server/compare/2.0.5...2.1.0
+[2.0.5]: https://github.com/thephpleague/oauth2-server/compare/2.0.4...2.0.5
+[2.0.4]: https://github.com/thephpleague/oauth2-server/compare/2.0.3...2.0.4
+[2.0.3]: https://github.com/thephpleague/oauth2-server/compare/2.0.2...2.0.3
+[2.0.2]: https://github.com/thephpleague/oauth2-server/compare/2.0.0...2.0.2
+[2.0.0]: https://github.com/thephpleague/oauth2-server/compare/1.0.8...2.0.0
+[1.0.8]: https://github.com/thephpleague/oauth2-server/compare/1.0.7...1.0.8
+[1.0.7]: https://github.com/thephpleague/oauth2-server/compare/1.0.6...1.0.7
+[1.0.6]: https://github.com/thephpleague/oauth2-server/compare/1.0.5...1.0.6
+[1.0.5]: https://github.com/thephpleague/oauth2-server/compare/1.0.3...1.0.5
+[1.0.3]: https://github.com/thephpleague/oauth2-server/compare/1.0.2...1.0.3
+[1.0.2]: https://github.com/thephpleague/oauth2-server/compare/1.0.1...1.0.2
+[1.0.1]: https://github.com/thephpleague/oauth2-server/compare/1.0.0...1.0.1
--- 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
@@ -6,10 +6,11 @@
 [![Coverage Status](https://img.shields.io/scrutinizer/coverage/g/thephpleague/oauth2-server.svg?style=flat-square)](https://scrutinizer-ci.com/g/thephpleague/oauth2-server/code-structure)
 [![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)
+[![PHPStan](https://img.shields.io/badge/PHPStan-enabled-brightgreen.svg?style=flat-square)](https://github.com/phpstan/phpstan)

 `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:
+Out of the box it supports the following grants:

 * Authorization code grant
 * Implicit grant
@@ -30,26 +31,48 @@ This library was created by Alex Bilbie. Find him on Twitter at [@alexbilbie](ht

 The following versions of PHP are supported:

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

 The `openssl` extension is also required.

+## Installation
+
+```
+composer require league/oauth2-server
+```
+
 ## Documentation

-The library documentation can be found at [https://oauth2.thephpleague.com](https://oauth2.thephpleague.com). 
+The library documentation can be found at [https://oauth2.thephpleague.com](https://oauth2.thephpleague.com).
 You can contribute to the documentation in the [gh-pages branch](https://github.com/thephpleague/oauth2-server/tree/gh-pages/).

+## Testing
+
+The library uses [PHPUnit](https://phpunit.de/) for unit tests and [PHPStan](https://github.com/phpstan/phpstan) for static analysis of the code.
+
+```
+vendor/bin/phpunit
+vendor/bin/phpstan analyse -l 6 -c phpstan.neon src tests
+```
+
+## Continous Integration
+
+We use [Travis CI](https://travis-ci.org/), [Scrutinizer](https://scrutinizer-ci.com/), and [StyleCI](https://styleci.io/) for continuous integration. Check out [our](https://github.com/thephpleague/oauth2-server/blob/master/.travis.yml) [configuration](https://github.com/thephpleague/oauth2-server/blob/master/.scrutinizer.yml) [files](https://github.com/thephpleague/oauth2-server/blob/master/.styleci.yml) if you'd like to know more.
+
+## Community Integrations
+
+* [Laravel Passport](https://github.com/laravel/passport)
+* [OAuth 2 Server for CakePHP 3](https://github.com/uafrica/oauth-server)
+
 ## Changelog

-[See the project releases page](https://github.com/thephpleague/oauth2-server/releases)
+See the [project changelog](https://github.com/thephpleague/oauth2-server/blob/master/CHANGELOG.md)

 ## Contributing

-Please see [CONTRIBUTING.md](https://github.com/thephpleague/oauth2-server/blob/master/CONTRIBUTING.md) and [CONDUCT.md](https://github.com/thephpleague/oauth2-server/blob/master/CONDUCT.md) for details.
+Contributions are always welcome. Please see [CONTRIBUTING.md](https://github.com/thephpleague/oauth2-server/blob/master/CONTRIBUTING.md) and [CONDUCT.md](https://github.com/thephpleague/oauth2-server/blob/master/CONDUCT.md) for details.

 ## Support

@@ -71,7 +94,11 @@ 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) and [Simon Hamp](https://twitter.com/simonhamp).
+
+Between 2012 and 2017 this library was developed and maintained by [Alex Bilbie](https://alexbilbie.com/).
+
+PHP OAuth 2.0 Server is one of many packages provided by The PHP League. To find out more, please visit [our website](https://thephpleague.com).

 Special thanks to [all of these awesome contributors](https://github.com/thephpleague/oauth2-server/contributors).

--- a/composer.json
+++ b/composer.json
@@ -4,18 +4,20 @@
    "homepage": "https://oauth2.thephpleague.com/",
    "license": "MIT",
    "require": {
-        "php": ">=5.5.9",
+        "php": ">=7.0.0",
        "ext-openssl": "*",
        "league/event": "^2.1",
-        "lcobucci/jwt": "^3.1",
+        "lcobucci/jwt": "^3.2.2",
        "paragonie/random_compat": "^2.0",
-        "psr/http-message": "^1.0",
+        "psr/http-message": "^1.0.1",
        "defuse/php-encryption": "^2.1"
    },
    "require-dev": {
-        "phpunit/phpunit": "^4.8 || ^5.0",
-        "zendframework/zend-diactoros": "^1.0",
-        "indigophp/hash-compat": "^1.1"
+        "phpunit/phpunit": "^6.3 || ^7.0",
+        "zendframework/zend-diactoros": "^1.3.2",
+        "phpstan/phpstan": "^0.9.2",
+        "phpstan/phpstan-phpunit": "^0.9.4",
+        "phpstan/phpstan-strict-rules": "^0.9.0"
    },
    "repositories": [
        {
@@ -60,13 +62,5 @@
        "psr-4": {
            "LeagueTests\\": "tests/"
        }
-    },
-    "extra": {
-        "branch-alias": {
-            "dev-V5-WIP": "5.0-dev"
-        }
-    },
-    "suggest": {
-        "indigophp/hash-compat": "Polyfill for hash_equals function for PHP 5.5"
    }
 }
--- a/examples/composer.json
+++ b/examples/composer.json
@@ -7,7 +7,8 @@
        "lcobucci/jwt": "^3.1",
        "paragonie/random_compat": "^2.0",
        "psr/http-message": "^1.0",
-        "defuse/php-encryption": "^2.1"
+        "defuse/php-encryption": "^2.1",
+        "zendframework/zend-diactoros": "^1.0"
    },
    "autoload": {
        "psr-4": {
--- a/examples/public/api.php
+++ b/examples/public/api.php
@@ -49,16 +49,18 @@ $app->get(
            ],
        ];

+        $totalUsers = count($users);
+
        // If the access token doesn't have the `basic` scope hide users' names
        if (in_array('basic', $request->getAttribute('oauth_scopes')) === false) {
-            for ($i = 0; $i < count($users); $i++) {
+            for ($i = 0; $i < $totalUsers; $i++) {
                unset($users[$i]['name']);
            }
        }

        // If the access token doesn't have the `email` scope hide users' email addresses
        if (in_array('email', $request->getAttribute('oauth_scopes')) === false) {
-            for ($i = 0; $i < count($users); $i++) {
+            for ($i = 0; $i < $totalUsers; $i++) {
                unset($users[$i]['email']);
            }
        }
--- 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(
@@ -44,9 +43,8 @@ $app = new App([
            $accessTokenRepository,
            $scopeRepository,
            $privateKeyPath,
-            $publicKeyPath
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
        );
-        $server->setEncryptionKey('lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen');

        // Enable the authentication code grant on the server with a token TTL of 1 hour
        $server->enableGrantType(
--- a/examples/public/client_credentials.php
+++ b/examples/public/client_credentials.php
@@ -32,7 +32,6 @@ $app = new App([
        // Path to public and private keys
        $privateKey = 'file://' . __DIR__ . '/../private.key';
        //$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(
@@ -40,9 +39,8 @@ $app = new App([
            $accessTokenRepository,
            $scopeRepository,
            $privateKey,
-            $publicKey
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
        );
-        $server->setEncryptionKey('lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen');

        // Enable the client credentials grant on the server
        $server->enableGrantType(
--- 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(
@@ -40,9 +39,8 @@ $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
@@ -38,7 +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(
@@ -46,9 +45,8 @@ $app = new App([
            $accessTokenRepository,
            $scopeRepository,
            $privateKeyPath,
-            $publicKeyPath
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
        );
-        $server->setEncryptionKey('lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen');

        // Enable the authentication code grant on the server with a token TTL of 1 hour
        $server->enableGrantType(
--- a/examples/public/password.php
+++ b/examples/public/password.php
@@ -24,9 +24,8 @@ $app = new App([
            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
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'      // encryption key
        );
-        $server->setEncryptionKey('lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen');

        $grant = new PasswordGrant(
            new UserRepository(),           // instance of UserRepositoryInterface
--- a/examples/public/refresh_token.php
+++ b/examples/public/refresh_token.php
@@ -32,7 +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(
@@ -40,9 +39,8 @@ $app = new App([
            $accessTokenRepository,
            $scopeRepository,
            $privateKeyPath,
-            $publicKeyPath
+            'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
        );
-        $server->setEncryptionKey('lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen');

        // Enable the refresh token grant on the server
        $grant = new RefreshTokenGrant($refreshTokenRepository);
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -0,0 +1,5 @@
+includes:
+	- vendor/phpstan/phpstan-phpunit/extension.neon
+	- vendor/phpstan/phpstan-phpunit/rules.neon
+	- vendor/phpstan/phpstan-phpunit/strictRules.neon
+	- vendor/phpstan/phpstan-strict-rules/rules.neon
--- a/src/AuthorizationServer.php
+++ b/src/AuthorizationServer.php
@@ -17,6 +17,7 @@ use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
 use League\OAuth2\Server\Repositories\ScopeRepositoryInterface;
 use League\OAuth2\Server\RequestTypes\AuthorizationRequest;
+use League\OAuth2\Server\ResponseTypes\AbstractResponseType;
 use League\OAuth2\Server\ResponseTypes\BearerTokenResponse;
 use League\OAuth2\Server\ResponseTypes\ResponseTypeInterface;
 use Psr\Http\Message\ResponseInterface;
@@ -26,8 +27,6 @@ class AuthorizationServer implements EmitterAwareInterface
 {
    use EmitterAwareTrait;

-    const ENCRYPTION_KEY_ERROR = 'You must set the encryption key going forward to improve the security of this library - see this page for more information https://oauth2.thephpleague.com/v5-security-improvements/';
-
    /**
     * @var GrantTypeInterface[]
     */
@@ -73,6 +72,11 @@ class AuthorizationServer implements EmitterAwareInterface
     */
    private $encryptionKey;

+    /**
+     * @var string
+     */
+    private $defaultScope = '';
+
    /**
     * New server instance.
     *
@@ -80,7 +84,7 @@ class AuthorizationServer implements EmitterAwareInterface
     * @param AccessTokenRepositoryInterface $accessTokenRepository
     * @param ScopeRepositoryInterface       $scopeRepository
     * @param CryptKey|string                $privateKey
-     * @param CryptKey|string                $publicKey
+     * @param string                         $encryptionKey
     * @param null|ResponseTypeInterface     $responseType
     */
    public function __construct(
@@ -88,7 +92,7 @@ class AuthorizationServer implements EmitterAwareInterface
        AccessTokenRepositoryInterface $accessTokenRepository,
        ScopeRepositoryInterface $scopeRepository,
        $privateKey,
-        $publicKey,
+        $encryptionKey,
        ResponseTypeInterface $responseType = null
    ) {
        $this->clientRepository = $clientRepository;
@@ -99,25 +103,10 @@ class AuthorizationServer implements EmitterAwareInterface
            $privateKey = new CryptKey($privateKey);
        }
        $this->privateKey = $privateKey;
-
-        if ($publicKey instanceof CryptKey === false) {
-            $publicKey = new CryptKey($publicKey);
-        }
-        $this->publicKey = $publicKey;
-
+        $this->encryptionKey = $encryptionKey;
        $this->responseType = $responseType;
    }

-    /**
-     * Set the encryption key
-     *
-     * @param string $key
-     */
-    public function setEncryptionKey($key)
-    {
-        $this->encryptionKey = $key;
-    }
-
    /**
     * Enable a grant type on the server.
     *
@@ -133,15 +122,9 @@ class AuthorizationServer implements EmitterAwareInterface
        $grantType->setAccessTokenRepository($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());
-
-        if ($this->encryptionKey === null) {
-            // @codeCoverageIgnoreStart
-            error_log(self::ENCRYPTION_KEY_ERROR);
-            // @codeCoverageIgnoreEnd
-        }
        $grantType->setEncryptionKey($this->encryptionKey);

        $this->enabledGrantTypes[$grantType->getIdentifier()] = $grantType;
@@ -159,12 +142,6 @@ class AuthorizationServer implements EmitterAwareInterface
     */
    public function validateAuthorizationRequest(ServerRequestInterface $request)
    {
-        if ($this->encryptionKey === null) {
-            // @codeCoverageIgnoreStart
-            error_log(self::ENCRYPTION_KEY_ERROR);
-            // @codeCoverageIgnoreEnd
-        }
-
        foreach ($this->enabledGrantTypes as $grantType) {
            if ($grantType->canRespondToAuthorizationRequest($request)) {
                return $grantType->validateAuthorizationRequest($request);
@@ -202,16 +179,17 @@ class AuthorizationServer implements EmitterAwareInterface
    public function respondToAccessTokenRequest(ServerRequestInterface $request, ResponseInterface $response)
    {
        foreach ($this->enabledGrantTypes as $grantType) {
-            if ($grantType->canRespondToAccessTokenRequest($request)) {
-                $tokenResponse = $grantType->respondToAccessTokenRequest(
-                    $request,
-                    $this->getResponseType(),
-                    $this->grantTypeAccessTokenTTL[$grantType->getIdentifier()]
-                );
+            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);
            }
        }

@@ -229,9 +207,21 @@ class AuthorizationServer implements EmitterAwareInterface
            $this->responseType = new BearerTokenResponse();
        }

-        $this->responseType->setPrivateKey($this->privateKey);
+        if ($this->responseType instanceof AbstractResponseType === true) {
+            $this->responseType->setPrivateKey($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;
@@ -26,6 +27,11 @@ class BearerTokenValidator implements AuthorizationValidatorInterface
     */
    private $accessTokenRepository;

+    /**
+     * @var \League\OAuth2\Server\CryptKey
+     */
+    protected $publicKey;
+
    /**
     * @param AccessTokenRepositoryInterface $accessTokenRepository
     */
@@ -34,6 +40,16 @@ class BearerTokenValidator implements AuthorizationValidatorInterface
        $this->accessTokenRepository = $accessTokenRepository;
    }

+    /**
+     * Set the public key
+     *
+     * @param \League\OAuth2\Server\CryptKey $key
+     */
+    public function setPublicKey(CryptKey $key)
+    {
+        $this->publicKey = $key;
+    }
+
    /**
     * {@inheritdoc}
     */
--- a/src/CryptKey.php
+++ b/src/CryptKey.php
@@ -14,7 +14,7 @@ namespace League\OAuth2\Server;
 class CryptKey
 {
    const RSA_KEY_PATTERN =
-        '/^(-----BEGIN (RSA )?(PUBLIC|PRIVATE) KEY-----\n)(.|\n)+(-----END (RSA )?(PUBLIC|PRIVATE) KEY-----)$/';
+        '/^(-----BEGIN (RSA )?(PUBLIC|PRIVATE) KEY-----)\R.*(-----END (RSA )?(PUBLIC|PRIVATE) KEY-----)\R?$/s';

    /**
     * @var string
@@ -29,8 +29,9 @@ class CryptKey
    /**
     * @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);
@@ -44,20 +45,15 @@ class CryptKey
            throw new \LogicException(sprintf('Key path "%s" does not exist or is not readable', $keyPath));
        }

-        // Verify the permissions of the key
-        $keyPathPerms = decoct(fileperms($keyPath) & 0777);
-        if ($keyPathPerms !== '600') {
-            // Attempt to correct the permissions
-            if (chmod($keyPath, 0600) === false) {
-                // @codeCoverageIgnoreStart
-                throw new \LogicException(
-                    sprintf(
-                        'Key file "%s" permissions are not correct, should be 600 instead of %s, unable to automatically resolve the issue',
-                        $keyPath,
-                        $keyPathPerms
-                    )
-                );
-                // @codeCoverageIgnoreEnd
+        if ($keyPermissionsCheck === true) {
+            // Verify the permissions of the key
+            $keyPathPerms = decoct(fileperms($keyPath) & 0777);
+            if (in_array($keyPathPerms, ['400', '440', '600', '660'], true) === false) {
+                trigger_error(sprintf(
+                    'Key file "%s" permissions are not correct, recommend changing to 600 or 660 instead of %s',
+                    $keyPath,
+                    $keyPathPerms
+                ), E_USER_NOTICE);
            }
        }

@@ -77,21 +73,25 @@ class CryptKey
        $tmpDir = sys_get_temp_dir();
        $keyPath = $tmpDir . '/' . sha1($key) . '.key';

-        if (!file_exists($keyPath) && !touch($keyPath)) {
+        if (file_exists($keyPath)) {
+            return 'file://' . $keyPath;
+        }
+
+        if (!touch($keyPath)) {
            // @codeCoverageIgnoreStart
-            throw new \RuntimeException('"%s" key file could not be created', $keyPath);
+            throw new \RuntimeException(sprintf('"%s" key file could not be created', $keyPath));
            // @codeCoverageIgnoreEnd
        }

        if (file_put_contents($keyPath, $key) === false) {
            // @codeCoverageIgnoreStart
-            throw new \RuntimeException('Unable to write key file to temporary directory "%s"', $tmpDir);
+            throw new \RuntimeException(sprintf('Unable to write key file to temporary directory "%s"', $tmpDir));
            // @codeCoverageIgnoreEnd
        }

        if (chmod($keyPath, 0600) === false) {
            // @codeCoverageIgnoreStart
-            throw new \RuntimeException('The key file "%s" file mode could not be changed with chmod to 600', $keyPath);
+            throw new \RuntimeException(sprintf('The key file "%s" file mode could not be changed with chmod to 600', $keyPath));
            // @codeCoverageIgnoreEnd
        }

--- a/src/CryptTrait.php
+++ b/src/CryptTrait.php
@@ -15,41 +15,11 @@ use Defuse\Crypto\Crypto;

 trait CryptTrait
 {
-    /**
-     * @var CryptKey
-     */
-    protected $privateKey;
-
-    /**
-     * @var CryptKey
-     */
-    protected $publicKey;
-
    /**
     * @var string
     */
    protected $encryptionKey;

-    /**
-     * Set path to private key.
-     *
-     * @param CryptKey $privateKey
-     */
-    public function setPrivateKey(CryptKey $privateKey)
-    {
-        $this->privateKey = $privateKey;
-    }
-
-    /**
-     * Set path to public key.
-     *
-     * @param CryptKey $publicKey
-     */
-    public function setPublicKey(CryptKey $publicKey)
-    {
-        $this->publicKey = $publicKey;
-    }
-
    /**
     * Encrypt data with a private key.
     *
@@ -61,34 +31,11 @@ trait CryptTrait
     */
    protected function encrypt($unencryptedData)
    {
-        if ($this->encryptionKey !== null) {
+        try {
            return Crypto::encryptWithPassword($unencryptedData, $this->encryptionKey);
+        } catch (\Exception $e) {
+            throw new \LogicException($e->getMessage());
        }
-
-        $privateKey = openssl_pkey_get_private($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())
-            );
-        }
-
-        $chunkSize = ceil($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);
    }

    /**
@@ -102,36 +49,11 @@ trait CryptTrait
     */
    protected function decrypt($encryptedData)
    {
-        if ($this->encryptionKey !== null) {
+        try {
            return Crypto::decryptWithPassword($encryptedData, $this->encryptionKey);
+        } catch (\Exception $e) {
+            throw new \LogicException($e->getMessage());
        }
-
-        $publicKey = openssl_pkey_get_public($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())
-            );
-        }
-
-        $chunkSize = ceil($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;
    }

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

 namespace League\OAuth2\Server\Entities;

+use Lcobucci\JWT\Token;
 use League\OAuth2\Server\CryptKey;

 interface AccessTokenEntityInterface extends TokenInterface
@@ -18,7 +19,7 @@ interface AccessTokenEntityInterface extends TokenInterface
     *
     * @param CryptKey $privateKey
     *
-     * @return string
+     * @return Token
     */
    public function convertToJWT(CryptKey $privateKey);
 }
--- a/src/Entities/RefreshTokenEntityInterface.php
+++ b/src/Entities/RefreshTokenEntityInterface.php
@@ -21,7 +21,7 @@ interface RefreshTokenEntityInterface
    /**
     * Set the token's identifier.
     *
-     * @param $identifier
+     * @param mixed $identifier
     */
    public function setIdentifier($identifier);

--- a/src/Entities/TokenInterface.php
+++ b/src/Entities/TokenInterface.php
@@ -21,7 +21,7 @@ interface TokenInterface
    /**
     * Set the token's identifier.
     *
-     * @param $identifier
+     * @param mixed $identifier
     */
    public function setIdentifier($identifier);

@@ -42,14 +42,14 @@ interface TokenInterface
    /**
     * Set the identifier of the user associated with the token.
     *
-     * @param string|int $identifier The identifier of the user
+     * @param string|int|null $identifier The identifier of the user
     */
    public function setUserIdentifier($identifier);

    /**
     * Get the token user's identifier.
     *
-     * @return string|int
+     * @return string|int|null
     */
    public function getUserIdentifier();

--- a/src/Entities/Traits/AccessTokenTrait.php
+++ b/src/Entities/Traits/AccessTokenTrait.php
@@ -12,6 +12,7 @@ namespace League\OAuth2\Server\Entities\Traits;
 use Lcobucci\JWT\Builder;
 use Lcobucci\JWT\Signer\Key;
 use Lcobucci\JWT\Signer\Rsa\Sha256;
+use Lcobucci\JWT\Token;
 use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\ClientEntityInterface;
 use League\OAuth2\Server\Entities\ScopeEntityInterface;
@@ -23,7 +24,7 @@ trait AccessTokenTrait
     *
     * @param CryptKey $privateKey
     *
-     * @return string
+     * @return Token
     */
    public function convertToJWT(CryptKey $privateKey)
    {
--- a/src/Entities/Traits/EntityTrait.php
+++ b/src/Entities/Traits/EntityTrait.php
@@ -11,7 +11,7 @@ namespace League\OAuth2\Server\Entities\Traits;

 trait EntityTrait
 {
-    /*
+    /**
     * @var string
     */
    protected $identifier;
--- a/src/Entities/Traits/TokenEntityTrait.php
+++ b/src/Entities/Traits/TokenEntityTrait.php
@@ -25,7 +25,7 @@ trait TokenEntityTrait
    protected $expiryDateTime;

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

@@ -77,7 +77,7 @@ trait TokenEntityTrait
    /**
     * Set the identifier of the user associated with the token.
     *
-     * @param string|int $identifier The identifier of the user
+     * @param string|int|null $identifier The identifier of the user
     */
    public function setUserIdentifier($identifier)
    {
@@ -87,7 +87,7 @@ trait TokenEntityTrait
    /**
     * Get the token user's identifier.
     *
-     * @return string|int
+     * @return string|int|null
     */
    public function getUserIdentifier()
    {
--- a/src/Exception/OAuthServerException.php
+++ b/src/Exception/OAuthServerException.php
@@ -33,6 +33,11 @@ class OAuthServerException extends \Exception
     */
    private $redirectUri;

+    /**
+     * @var array
+     */
+    private $payload;
+
    /**
     * Throw a new exception.
     *
@@ -50,6 +55,33 @@ class OAuthServerException extends \Exception
        $this->errorType = $errorType;
        $this->hint = $hint;
        $this->redirectUri = $redirectUri;
+        $this->payload = [
+            'error'   => $errorType,
+            'message' => $message,
+        ];
+        if ($hint !== null) {
+            $this->payload['hint'] = $hint;
+        }
+    }
+
+    /**
+     * Returns the current payload.
+     *
+     * @return array
+     */
+    public function getPayload()
+    {
+        return $this->payload;
+    }
+
+    /**
+     * Updates the current payload.
+     *
+     * @param array $payload
+     */
+    public function setPayload(array $payload)
+    {
+        $this->payload = $payload;
    }

    /**
@@ -105,10 +137,15 @@ class OAuthServerException extends \Exception
    public static function invalidScope($scope, $redirectUri = null)
    {
        $errorMessage = 'The requested scope is invalid, unknown, or malformed';
-        $hint = sprintf(
-            'Check the `%s` scope',
-            htmlspecialchars($scope, ENT_QUOTES, 'UTF-8', false)
-        );
+
+        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);
    }
@@ -126,7 +163,7 @@ class OAuthServerException extends \Exception
    /**
     * Server error.
     *
-     * @param $hint
+     * @param string $hint
     *
     * @return static
     *
@@ -152,7 +189,7 @@ class OAuthServerException extends \Exception
     */
    public static function invalidRefreshToken($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);
    }

    /**
@@ -208,21 +245,15 @@ class OAuthServerException extends \Exception
     *
     * @param ResponseInterface $response
     * @param bool              $useFragment True if errors should be in the URI fragment instead of query string
+     * @param int               $jsonOptions options passed to json_encode
     *
     * @return ResponseInterface
     */
-    public function generateHttpResponse(ResponseInterface $response, $useFragment = false)
+    public function generateHttpResponse(ResponseInterface $response, $useFragment = false, $jsonOptions = 0)
    {
        $headers = $this->getHttpHeaders();

-        $payload = [
-            'error'   => $this->getErrorType(),
-            'message' => $this->getMessage(),
-        ];
-
-        if ($this->hint !== null) {
-            $payload['hint'] = $this->hint;
-        }
+        $payload = $this->getPayload();

        if ($this->redirectUri !== null) {
            if ($useFragment === true) {
@@ -238,7 +269,7 @@ class OAuthServerException extends \Exception
            $response = $response->withHeader($header, $content);
        }

-        $response->getBody()->write(json_encode($payload));
+        $response->getBody()->write(json_encode($payload, $jsonOptions));

        return $response->withStatus($this->getHttpStatusCode());
    }
--- a/src/Grant/AbstractGrant.php
+++ b/src/Grant/AbstractGrant.php
@@ -11,6 +11,7 @@
 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;
@@ -75,6 +76,16 @@ abstract class AbstractGrant implements GrantTypeInterface
     */
    protected $refreshTokenTTL;

+    /**
+     * @var \League\OAuth2\Server\CryptKey
+     */
+    protected $privateKey;
+
+    /**
+     * @string
+     */
+    protected $defaultScope;
+
    /**
     * @param ClientRepositoryInterface $clientRepository
     */
@@ -131,6 +142,24 @@ 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 = $scope;
+    }
+
    /**
     * Validate the client.
     *
@@ -175,7 +204,7 @@ abstract class AbstractGrant implements GrantTypeInterface
                throw OAuthServerException::invalidClient();
            } elseif (
                is_array($client->getRedirectUri())
-                && in_array($redirectUri, $client->getRedirectUri()) === false
+                && in_array($redirectUri, $client->getRedirectUri(), true) === false
            ) {
                $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
                throw OAuthServerException::invalidClient();
@@ -195,18 +224,14 @@ abstract class AbstractGrant implements GrantTypeInterface
     *
     * @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);

@@ -214,10 +239,10 @@ abstract class AbstractGrant implements GrantTypeInterface
                throw OAuthServerException::invalidScope($scopeItem, $redirectUri);
            }

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

-        return $scopes;
+        return $validScopes;
    }

    /**
@@ -316,7 +341,7 @@ abstract class AbstractGrant implements GrantTypeInterface
     *
     * @param \DateInterval          $accessTokenTTL
     * @param ClientEntityInterface  $client
-     * @param string                 $userIdentifier
+     * @param string|null            $userIdentifier
     * @param ScopeEntityInterface[] $scopes
     *
     * @throws OAuthServerException
--- a/src/Grant/AuthCodeGrant.php
+++ b/src/Grant/AuthCodeGrant.php
@@ -134,6 +134,15 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
                throw OAuthServerException::invalidRequest('code_verifier');
            }

+            // Validate code_verifier according to RFC-7636
+            // @see: https://tools.ietf.org/html/rfc7636#section-4.1
+            if (preg_match('/^[A-Za-z0-9-._~]{43,128}$/', $codeVerifier) !== 1) {
+                throw OAuthServerException::invalidRequest(
+                    'code_verifier',
+                    'Code Verifier must follow the specifications of RFC-7636.'
+                );
+            }
+
            switch ($authCodePayload->code_challenge_method) {
                case 'plain':
                    if (hash_equals($codeVerifier, $authCodePayload->code_challenge) === false) {
@@ -144,7 +153,7 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
                case 'S256':
                    if (
                        hash_equals(
-                            urlencode(base64_encode(hash('sha256', $codeVerifier))),
+                            strtr(rtrim(base64_encode(hash('sha256', $codeVerifier, true)), '='), '+/', '-_'),
                            $authCodePayload->code_challenge
                        ) === false
                    ) {
@@ -235,18 +244,24 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
                throw OAuthServerException::invalidClient();
            } elseif (
                is_array($client->getRedirectUri())
-                && in_array($redirectUri, $client->getRedirectUri()) === false
+                && in_array($redirectUri, $client->getRedirectUri(), true) === false
            ) {
                $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();
+        } else {
+            $redirectUri = is_array($client->getRedirectUri())
+                ? $client->getRedirectUri()[0]
+                : $client->getRedirectUri();
        }

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

        $stateParameter = $this->getQueryStringParameter('state', $request);
@@ -264,21 +279,23 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
                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) {
+            if (in_array($codeChallengeMethod, ['plain', 'S256'], true) === false) {
                throw OAuthServerException::invalidRequest(
                    'code_challenge_method',
                    'Code challenge method must be `plain` or `S256`'
                );
            }

+            // Validate code_challenge according to RFC-7636
+            // @see: https://tools.ietf.org/html/rfc7636#section-4.2
+            if (preg_match('/^[A-Za-z0-9-._~]{43,128}$/', $codeChallenge) !== 1) {
+                throw OAuthServerException::invalidRequest(
+                    'code_challenged',
+                    'Code challenge must follow the specifications of RFC-7636.'
+                );
+            }
+
            $authorizationRequest->setCodeChallenge($codeChallenge);
            $authorizationRequest->setCodeChallengeMethod($codeChallengeMethod);
        }
@@ -312,30 +329,16 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
            );

            $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(),
+                '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(),
            ];

-            if ($this->encryptionKey === null) {
-                // Add padding to vary the length of the payload
-                $payload['_padding'] = base64_encode(random_bytes(mt_rand(8, 256)));
-                // Shuffle the payload so that the structure is no longer know and obvious
-                $keys = array_keys($payload);
-                shuffle($keys);
-                $shuffledPayload = [];
-                foreach ($keys as $key) {
-                    $shuffledPayload[$key] = $payload[$key];
-                }
-            } else {
-                $shuffledPayload = $payload;
-            }
-
            $response = new RedirectResponse();
            $response->setRedirectUri(
                $this->makeRedirectUri(
@@ -343,7 +346,7 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
                    [
                        'code'  => $this->encrypt(
                            json_encode(
-                                $shuffledPayload
+                                $payload
                            )
                        ),
                        'state' => $authorizationRequest->getState(),
--- a/src/Grant/ClientCredentialsGrant.php
+++ b/src/Grant/ClientCredentialsGrant.php
@@ -29,13 +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
@@ -119,6 +119,13 @@ interface GrantTypeInterface extends EmitterAwareInterface
     */
    public function setScopeRepository(ScopeRepositoryInterface $scopeRepository);

+    /**
+     * Set the default scope.
+     *
+     * @param string $scope
+     */
+    public function setDefaultScope($scope);
+
    /**
     * Set the path to the private key.
     *
@@ -126,13 +133,6 @@ interface GrantTypeInterface extends EmitterAwareInterface
     */
    public function setPrivateKey(CryptKey $privateKey);

-    /**
-     * Set the path to the public key.
-     *
-     * @param CryptKey $publicKey
-     */
-    public function setPublicKey(CryptKey $publicKey);
-
    /**
     * Set the encryption key
     *
--- 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;
    }

    /**
@@ -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'])
        );
@@ -137,22 +144,28 @@ class ImplicitGrant extends AbstractAuthorizeGrant
                throw OAuthServerException::invalidClient();
            } elseif (
                is_array($client->getRedirectUri())
-                && in_array($redirectUri, $client->getRedirectUri()) === false
+                && in_array($redirectUri, $client->getRedirectUri(), true) === false
            ) {
                $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();
+        } else {
+            $redirectUri = is_array($client->getRedirectUri())
+                ? $client->getRedirectUri()[0]
+                : $client->getRedirectUri();
        }

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

        // Finalize the requested scopes
-        $scopes = $this->scopeRepository->finalizeScopes(
+        $finalizedScopes = $this->scopeRepository->finalizeScopes(
            $scopes,
            $this->getIdentifier(),
            $client
@@ -165,7 +178,7 @@ class ImplicitGrant extends AbstractAuthorizeGrant
        $authorizationRequest->setClient($client);
        $authorizationRequest->setRedirectUri($redirectUri);
        $authorizationRequest->setState($stateParameter);
-        $authorizationRequest->setScopes($scopes);
+        $authorizationRequest->setScopes($finalizedScopes);

        return $authorizationRequest;
    }
@@ -200,11 +213,11 @@ 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
                )
            );

--- a/src/Grant/PasswordGrant.php
+++ b/src/Grant/PasswordGrant.php
@@ -49,14 +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
--- a/src/Grant/RefreshTokenGrant.php
+++ b/src/Grant/RefreshTokenGrant.php
@@ -11,7 +11,6 @@

 namespace League\OAuth2\Server\Grant;

-use League\OAuth2\Server\Entities\ScopeEntityInterface;
 use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface;
 use League\OAuth2\Server\RequestEvent;
@@ -44,28 +43,17 @@ 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 ($scope instanceof ScopeEntityInterface === false) {
-                    // @codeCoverageIgnoreStart
-                    throw OAuthServerException::invalidScope($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(), $oldRefreshToken['scopes'], true) === false) {
+                throw OAuthServerException::invalidScope($scope->getIdentifier());
            }
        }

--- a/src/Repositories/AccessTokenRepositoryInterface.php
+++ b/src/Repositories/AccessTokenRepositoryInterface.php
@@ -12,6 +12,7 @@ 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.
@@ -33,6 +34,8 @@ interface AccessTokenRepositoryInterface extends RepositoryInterface
     * Persists a new access token to permanent storage.
     *
     * @param AccessTokenEntityInterface $accessTokenEntity
+     *
+     * @throws UniqueTokenIdentifierConstraintViolationException
     */
    public function persistNewAccessToken(AccessTokenEntityInterface $accessTokenEntity);

--- a/src/Repositories/AuthCodeRepositoryInterface.php
+++ b/src/Repositories/AuthCodeRepositoryInterface.php
@@ -10,6 +10,7 @@
 namespace League\OAuth2\Server\Repositories;

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

 /**
 * Auth code storage interface.
@@ -27,6 +28,8 @@ interface AuthCodeRepositoryInterface extends RepositoryInterface
     * Persists a new auth code to permanent storage.
     *
     * @param AuthCodeEntityInterface $authCodeEntity
+     *
+     * @throws UniqueTokenIdentifierConstraintViolationException
     */
    public function persistNewAuthCode(AuthCodeEntityInterface $authCodeEntity);

--- a/src/Repositories/ClientRepositoryInterface.php
+++ b/src/Repositories/ClientRepositoryInterface.php
@@ -20,12 +20,12 @@ interface ClientRepositoryInterface extends RepositoryInterface
     * Get a client.
     *
     * @param string      $clientIdentifier   The client's identifier
-     * @param string      $grantType          The grant type used
+     * @param null|string $grantType          The grant type used (if sent)
     * @param null|string $clientSecret       The client's secret (if sent)
     * @param bool        $mustValidateSecret If true the client must attempt to validate the secret if the client
     *                                        is confidential
     *
     * @return ClientEntityInterface
     */
-    public function getClientEntity($clientIdentifier, $grantType, $clientSecret = null, $mustValidateSecret = true);
+    public function getClientEntity($clientIdentifier, $grantType = null, $clientSecret = null, $mustValidateSecret = true);
 }
--- a/src/Repositories/RefreshTokenRepositoryInterface.php
+++ b/src/Repositories/RefreshTokenRepositoryInterface.php
@@ -10,6 +10,7 @@
 namespace League\OAuth2\Server\Repositories;

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

 /**
 * Refresh token interface.
@@ -27,6 +28,8 @@ interface RefreshTokenRepositoryInterface extends RepositoryInterface
     * Create a new refresh token_name.
     *
     * @param RefreshTokenEntityInterface $refreshTokenEntity
+     *
+     * @throws UniqueTokenIdentifierConstraintViolationException
     */
    public function persistNewRefreshToken(RefreshTokenEntityInterface $refreshTokenEntity);

--- a/src/RequestTypes/AuthorizationRequest.php
+++ b/src/RequestTypes/AuthorizationRequest.php
@@ -53,7 +53,7 @@ class AuthorizationRequest
    /**
     * The redirect URI used in the request
     *
-     * @var string
+     * @var string|null
     */
    protected $redirectUri;

@@ -159,7 +159,7 @@ class AuthorizationRequest
    }

    /**
-     * @return string
+     * @return string|null
     */
    public function getRedirectUri()
    {
@@ -167,7 +167,7 @@ class AuthorizationRequest
    }

    /**
-     * @param string $redirectUri
+     * @param string|null $redirectUri
     */
    public function setRedirectUri($redirectUri)
    {
--- a/src/ResourceServer.php
+++ b/src/ResourceServer.php
@@ -63,7 +63,9 @@ class ResourceServer
            $this->authorizationValidator = new BearerTokenValidator($this->accessTokenRepository);
        }

-        $this->authorizationValidator->setPublicKey($this->publicKey);
+        if ($this->authorizationValidator instanceof BearerTokenValidator === true) {
+            $this->authorizationValidator->setPublicKey($this->publicKey);
+        }

        return $this->authorizationValidator;
    }
--- a/src/ResponseTypes/AbstractResponseType.php
+++ b/src/ResponseTypes/AbstractResponseType.php
@@ -11,6 +11,7 @@

 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;
@@ -29,6 +30,11 @@ abstract class AbstractResponseType implements ResponseTypeInterface
     */
    protected $refreshToken;

+    /**
+     * @var CryptKey
+     */
+    protected $privateKey;
+
    /**
     * {@inheritdoc}
     */
@@ -44,4 +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/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;
@@ -17,15 +16,27 @@ 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 PHPUnit\Framework\TestCase;
 use Psr\Http\Message\ResponseInterface;
 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);
+        chmod(__DIR__ . '/Stubs/private.key.crlf', 0600);
+    }
+
    public function testRespondToRequestInvalidGrantType()
    {
        $server = new AuthorizationServer(
@@ -33,10 +44,9 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
            $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()
        );
-        $server->setEncryptionKey(base64_encode(random_bytes(36)));

        $server->enableGrantType(new ClientCredentialsGrant(), new \DateInterval('PT1M'));

@@ -53,7 +63,9 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
        $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->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
@@ -64,11 +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->setEncryptionKey(base64_encode(random_bytes(36)));

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

        $_POST['grant_type'] = 'client_credentials';
@@ -89,13 +101,12 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
            'file://' . __DIR__ . '/Stubs/private.key',
            'file://' . __DIR__ . '/Stubs/public.key'
        );
-        $server->setEncryptionKey(base64_encode(random_bytes(36)));

        $abstractGrantReflection = new \ReflectionClass($server);
        $method = $abstractGrantReflection->getMethod('getResponseType');
        $method->setAccessible(true);

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

    public function testCompleteAuthorizationRequest()
@@ -109,7 +120,6 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
            'file://' . __DIR__ . '/Stubs/private.key',
            'file://' . __DIR__ . '/Stubs/public.key'
        );
-        $server->setEncryptionKey(base64_encode(random_bytes(36)));

        $authCodeRepository = $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock();
        $authCodeRepository->method('getNewAuthCode')->willReturn(new AuthCodeEntity());
@@ -120,9 +130,6 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
            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();
@@ -131,12 +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();
@@ -156,7 +210,6 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
            'file://' . __DIR__ . '/Stubs/private.key',
            'file://' . __DIR__ . '/Stubs/public.key'
        );
-        $server->setEncryptionKey(base64_encode(random_bytes(36)));
        $server->enableGrantType($grant);

        $request = new ServerRequest(
@@ -173,7 +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());
+        }
    }

    /**
@@ -189,7 +247,6 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
            'file://' . __DIR__ . '/Stubs/private.key',
            'file://' . __DIR__ . '/Stubs/public.key'
        );
-        $server->setEncryptionKey(base64_encode(random_bytes(36)));

        $request = new ServerRequest(
            [],
--- a/tests/CryptTraitTest.php
+++ b/tests/CryptTraitTest.php
@@ -1,55 +0,0 @@
-<?php
-
-namespace LeagueTests\Utils;
-
-use League\OAuth2\Server\CryptKey;
-use LeagueTests\Stubs\CryptTraitStub;
-
-class CryptTraitTest extends \PHPUnit_Framework_TestCase
-{
-    /**
-     * CryptTrait stub
-     */
-    protected $cryptStub;
-
-    public function setUp()
-    {
-        $this->cryptStub = new CryptTraitStub;
-    }
-
-    public function testEncryptDecrypt()
-    {
-        $payload = 'alex loves whisky';
-        $encrypted = $this->cryptStub->doEncrypt($payload);
-        $plainText = $this->cryptStub->doDecrypt($encrypted);
-
-        $this->assertNotEquals($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;
@@ -19,16 +18,15 @@ 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());
    }

@@ -344,7 +342,7 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
        $accessToken = new AccessTokenEntity();
        /** @var RefreshTokenEntityInterface $refreshToken */
        $refreshToken = $issueRefreshTokenMethod->invoke($grantMock, $accessToken);
-        $this->assertTrue($refreshToken instanceof RefreshTokenEntityInterface);
+        $this->assertInstanceOf(RefreshTokenEntityInterface::class, $refreshToken);
        $this->assertEquals($accessToken, $refreshToken->getAccessToken());
    }

@@ -369,7 +367,7 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
            123,
            [new ScopeEntity()]
        );
-        $this->assertTrue($accessToken instanceof AccessTokenEntityInterface);
+        $this->assertInstanceOf(AccessTokenEntityInterface::class, $accessToken);
    }

    public function testIssueAuthCode()
@@ -385,7 +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'),
@@ -393,7 +392,7 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
                123,
                'http://foo/bar',
                [new ScopeEntity()]
-            ) instanceof AuthCodeEntityInterface
+            )
        );
    }

@@ -469,7 +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
@@ -2,7 +2,6 @@

 namespace LeagueTests\Grant;

-use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
 use League\OAuth2\Server\Exception\OAuthServerException;
@@ -23,15 +22,22 @@ 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 AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
+class AuthCodeGrantTest extends TestCase
 {
+    const DEFAULT_SCOPE = 'basic';
+
    /**
     * @var CryptTraitStub
     */
    protected $cryptStub;

+    const CODE_VERIFIER = 'dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk';
+
+    const CODE_CHALLENGE = 'E9Melhoa2OwvFrEMTJguCHaoeK1t8URWbuGJSstw-cM';
+
    public function setUp()
    {
        $this->cryptStub = new CryptTraitStub;
@@ -77,15 +83,22 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
    {
        $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);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $request = new ServerRequest(
            [],
@@ -102,7 +115,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            ]
        );

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

    public function testValidateAuthorizationRequestRedirectUriArray()
@@ -112,12 +125,18 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $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);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $request = new ServerRequest(
            [],
@@ -134,7 +153,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            ]
        );

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

    public function testValidateAuthorizationRequestCodeChallenge()
@@ -144,6 +163,10 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $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(),
@@ -151,6 +174,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        );
        $grant->enableCodeExchangeProof();
        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $request = new ServerRequest(
            [],
@@ -164,11 +189,11 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
                'response_type'  => 'code',
                'client_id'      => 'foo',
                'redirect_uri'   => 'http://foo/bar',
-                'code_challenge' => str_repeat('A', 43),
+                'code_challenge' => self::CODE_CHALLENGE,
            ]
        );

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

    /**
@@ -429,6 +454,10 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $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(),
@@ -436,6 +465,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        );
        $grant->enableCodeExchangeProof();
        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $request = new ServerRequest(
            [],
@@ -466,6 +497,10 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $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(),
@@ -473,6 +508,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        );
        $grant->enableCodeExchangeProof();
        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $request = new ServerRequest(
            [],
@@ -510,11 +547,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
            new \DateInterval('PT10M')
        );
+        $grant->setEncryptionKey($this->cryptStub->getKey());

-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-
-        $this->assertTrue($grant->completeAuthorizationRequest($authRequest) instanceof RedirectResponse);
+        $this->assertInstanceOf(RedirectResponse::class, $grant->completeAuthorizationRequest($authRequest));
    }

    /**
@@ -537,9 +572,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            $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'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $grant->completeAuthorizationRequest($authRequest);
    }
@@ -574,8 +607,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setScopeRepository($scopeRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -608,8 +640,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        /** @var StubResponseType $response */
        $response = $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));

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

    public function testRespondToAccessTokenRequestCodeChallengePlain()
@@ -643,8 +675,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setScopeRepository($scopeRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -659,7 +690,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
                'grant_type'    => 'authorization_code',
                'client_id'     => 'foo',
                'redirect_uri'  => 'http://foo/bar',
-                'code_verifier' => 'foobar',
+                'code_verifier' => self::CODE_VERIFIER,
                'code'          => $this->cryptStub->doEncrypt(
                    json_encode(
                        [
@@ -669,7 +700,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
                            'user_id'               => 123,
                            'scopes'                => ['foo'],
                            'redirect_uri'          => 'http://foo/bar',
-                            'code_challenge'        => 'foobar',
+                            'code_challenge'        => self::CODE_VERIFIER,
                            'code_challenge_method' => 'plain',
                        ]
                    )
@@ -680,8 +711,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        /** @var StubResponseType $response */
        $response = $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));

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

    public function testRespondToAccessTokenRequestCodeChallengeS256()
@@ -715,8 +746,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setScopeRepository($scopeRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -731,7 +761,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
                'grant_type'    => 'authorization_code',
                'client_id'     => 'foo',
                'redirect_uri'  => 'http://foo/bar',
-                'code_verifier' => 'foobar',
+                'code_verifier' => self::CODE_VERIFIER,
                'code'          => $this->cryptStub->doEncrypt(
                    json_encode(
                        [
@@ -741,7 +771,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
                            'user_id'               => 123,
                            'scopes'                => ['foo'],
                            'redirect_uri'          => 'http://foo/bar',
-                            'code_challenge'        => urlencode(base64_encode(hash('sha256', 'foobar'))),
+                            'code_challenge'        => self::CODE_CHALLENGE,
                            'code_challenge_method' => 'S256',
                        ]
                    )
@@ -752,8 +782,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        /** @var StubResponseType $response */
        $response = $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));

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

    /**
@@ -773,7 +803,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            new \DateInterval('PT10M')
        );
        $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -820,7 +850,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            new \DateInterval('PT10M')
        );
        $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -873,8 +903,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -919,8 +948,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -983,8 +1011,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -1044,8 +1071,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -1105,8 +1131,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -1164,8 +1189,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
        $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -1180,7 +1204,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
                'grant_type'    => 'authorization_code',
                'client_id'     => 'foo',
                'redirect_uri'  => 'http://foo/bar',
-                'code_verifier' => 'nope',
+                'code_verifier' => self::CODE_VERIFIER,
                'code'          => $this->cryptStub->doEncrypt(
                    json_encode(
                        [
@@ -1237,8 +1261,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
        $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -1275,7 +1298,151 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            /* @var StubResponseType $response */
            $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
        } catch (OAuthServerException $e) {
-            $this->assertEquals($e->getHint(), 'Failed to verify `code_verifier`.');
+            $this->assertEquals($e->getHint(), 'Code Verifier must follow the specifications of RFC-7636.');
+        }
+    }
+
+    public function testRespondToAccessTokenRequestMalformedCodeVerifierS256WithInvalidChars()
+    {
+        $client = new ClientEntity();
+        $client->setIdentifier('foo');
+        $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);
+
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willReturnSelf();
+
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
+        $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willReturnSelf();
+        $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
+
+        $grant = new AuthCodeGrant(
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+        $grant->enableCodeExchangeProof();
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setEncryptionKey($this->cryptStub->getKey());
+
+        $request = new ServerRequest(
+            [],
+            [],
+            null,
+            'POST',
+            'php://input',
+            [],
+            [],
+            [],
+            [
+                'grant_type'    => 'authorization_code',
+                'client_id'     => 'foo',
+                'redirect_uri'  => 'http://foo/bar',
+                'code_verifier' => 'dqX7C-RbqjHYtytmhGTigKdZCXfxq-+xbsk9_GxUcaE', // Malformed code. Contains `+`.
+                'code'          => $this->cryptStub->doEncrypt(
+                    json_encode(
+                        [
+                            'auth_code_id'          => uniqid(),
+                            'expire_time'           => time() + 3600,
+                            'client_id'             => 'foo',
+                            'user_id'               => 123,
+                            'scopes'                => ['foo'],
+                            'redirect_uri'          => 'http://foo/bar',
+                            'code_challenge'        => self::CODE_CHALLENGE,
+                            'code_challenge_method' => 'S256',
+                        ]
+                    )
+                ),
+            ]
+        );
+
+        try {
+            /* @var StubResponseType $response */
+            $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+        } catch (OAuthServerException $e) {
+            $this->assertEquals($e->getHint(), 'Code Verifier must follow the specifications of RFC-7636.');
+        }
+    }
+
+    public function testRespondToAccessTokenRequestMalformedCodeVerifierS256WithInvalidLength()
+    {
+        $client = new ClientEntity();
+        $client->setIdentifier('foo');
+        $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);
+
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willReturnSelf();
+
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
+        $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willReturnSelf();
+        $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
+
+        $grant = new AuthCodeGrant(
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+        $grant->enableCodeExchangeProof();
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setEncryptionKey($this->cryptStub->getKey());
+
+        $request = new ServerRequest(
+            [],
+            [],
+            null,
+            'POST',
+            'php://input',
+            [],
+            [],
+            [],
+            [
+                'grant_type'    => 'authorization_code',
+                'client_id'     => 'foo',
+                'redirect_uri'  => 'http://foo/bar',
+                'code_verifier' => 'dqX7C-RbqjHY', // Malformed code. Invalid length.
+                'code'          => $this->cryptStub->doEncrypt(
+                    json_encode(
+                        [
+                            'auth_code_id'          => uniqid(),
+                            'expire_time'           => time() + 3600,
+                            'client_id'             => 'foo',
+                            'user_id'               => 123,
+                            'scopes'                => ['foo'],
+                            'redirect_uri'          => 'http://foo/bar',
+                            'code_challenge'        => 'R7T1y1HPNFvs1WDCrx4lfoBS6KD2c71pr8OHvULjvv8',
+                            'code_challenge_method' => 'S256',
+                        ]
+                    )
+                ),
+            ]
+        );
+
+        try {
+            /* @var StubResponseType $response */
+            $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+        } catch (OAuthServerException $e) {
+            $this->assertEquals($e->getHint(), 'Code Verifier must follow the specifications of RFC-7636.');
        }
    }

@@ -1310,8 +1477,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
        $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -1370,11 +1536,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
            new \DateInterval('PT10M')
        );
+        $grant->setEncryptionKey($this->cryptStub->getKey());

-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-
-        $this->assertTrue($grant->completeAuthorizationRequest($authRequest) instanceof RedirectResponse);
+        $this->assertInstanceOf(RedirectResponse::class, $grant->completeAuthorizationRequest($authRequest));
    }

    /**
@@ -1398,11 +1562,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
            new \DateInterval('PT10M')
        );
+        $grant->setEncryptionKey($this->cryptStub->getKey());

-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-
-        $this->assertTrue($grant->completeAuthorizationRequest($authRequest) instanceof RedirectResponse);
+        $this->assertInstanceOf(RedirectResponse::class, $grant->completeAuthorizationRequest($authRequest));
    }

    /**
@@ -1427,10 +1589,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
            new \DateInterval('PT10M')
        );

-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-
-        $this->assertTrue($grant->completeAuthorizationRequest($authRequest) instanceof RedirectResponse);
+        $this->assertInstanceOf(RedirectResponse::class, $grant->completeAuthorizationRequest($authRequest));
    }

    public function testRefreshTokenRepositoryUniqueConstraintCheck()
@@ -1464,8 +1623,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setScopeRepository($scopeRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -1498,8 +1656,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        /** @var StubResponseType $response */
        $response = $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));

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

    /**
@@ -1536,8 +1694,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setScopeRepository($scopeRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -1570,8 +1727,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        /** @var StubResponseType $response */
        $response = $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));

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

    /**
@@ -1608,8 +1765,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        $grant->setScopeRepository($scopeRepositoryMock);
        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setEncryptionKey($this->cryptStub->getKey());

        $request = new ServerRequest(
            [],
@@ -1642,8 +1798,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
        /** @var StubResponseType $response */
        $response = $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));

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

    /**
--- 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();
@@ -30,13 +34,16 @@ 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(
@@ -49,6 +56,6 @@ class ClientCredentialsGrantTest extends \PHPUnit_Framework_TestCase
        $responseType = new StubResponseType();
        $grant->respondToAccessTokenRequest($serverRequest, $responseType, new \DateInterval('PT5M'));

-        $this->assertTrue($responseType->getAccessToken() instanceof AccessTokenEntityInterface);
+        $this->assertInstanceOf(AccessTokenEntityInterface::class, $responseType->getAccessToken());
    }
 }
--- a/tests/Grant/ImplicitGrantTest.php
+++ b/tests/Grant/ImplicitGrantTest.php
@@ -18,10 +18,13 @@ 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
     */
@@ -96,6 +99,7 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $request = new ServerRequest(
            [],
@@ -112,7 +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()
@@ -130,6 +134,7 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
        $grant->setClientRepository($clientRepositoryMock);
        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setDefaultScope(self::DEFAULT_SCOPE);

        $request = new ServerRequest(
            [],
@@ -146,7 +151,7 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
            ]
        );

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

    /**
@@ -283,10 +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));
    }

    /**
@@ -307,7 +311,6 @@ 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);
@@ -329,10 +332,9 @@ 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));
    }

    /**
@@ -354,7 +356,6 @@ 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);
@@ -379,7 +380,6 @@ 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);
--- a/tests/Grant/PasswordGrantTest.php
+++ b/tests/Grant/PasswordGrantTest.php
@@ -13,12 +13,16 @@ 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->getMockBuilder(UserRepositoryInterface::class)->getMock();
@@ -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());
    }

    /**
--- 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;

@@ -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
@@ -11,18 +11,24 @@ 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->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->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
@@ -33,11 +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->setEncryptionKey(base64_encode(random_bytes(36)));

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

        $_POST['grant_type'] = 'client_credentials';
@@ -67,10 +73,9 @@ class AuthorizationServerMiddlewareTest extends \PHPUnit_Framework_TestCase
            $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()
        );
-        $server->setEncryptionKey(base64_encode(random_bytes(36)));

        $server->enableGrantType(new ClientCredentialsGrant(), new \DateInterval('PT1M'));

@@ -99,7 +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()
@@ -108,6 +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
@@ -8,10 +8,11 @@ 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()
    {
--- a/tests/ResourceServerTest.php
+++ b/tests/ResourceServerTest.php
@@ -6,9 +6,10 @@ 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()
    {
--- a/tests/ResponseTypes/BearerResponseTypeTest.php
+++ b/tests/ResponseTypes/BearerResponseTypeTest.php
@@ -11,19 +11,18 @@ 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()
    {
-        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
-
-        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
+        $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');
@@ -47,7 +46,7 @@ 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]);
@@ -55,19 +54,17 @@ 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 = new BearerTokenResponseWithParams();
        $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');
@@ -91,7 +88,7 @@ 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]);
@@ -99,23 +96,20 @@ 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);

-        $this->assertTrue(isset($json->foo));
-        $this->assertEquals('bar', $json->foo);
+        $this->assertObjectHasAttribute('foo', $json);
+        $this->assertAttributeEquals('bar', 'foo', $json);
    }

    public function testDetermineAccessTokenInHeaderValidToken()
    {
-        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
-        $accessTokenRepositoryMock->method('isAccessTokenRevoked')->willReturn(false);
-
-        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
+        $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');
@@ -141,7 +135,6 @@ 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();
@@ -158,11 +151,10 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
    public function testDetermineAccessTokenInHeaderInvalidJWT()
    {
        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
-        $accessTokenRepositoryMock->method('isAccessTokenRevoked')->willReturn(false);

-        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
+        $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');
@@ -185,7 +177,6 @@ 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();
@@ -205,7 +196,7 @@ 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');
@@ -231,7 +222,6 @@ 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();
@@ -249,16 +239,13 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase

    public function testDetermineAccessTokenInHeaderInvalidToken()
    {
-        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
-
-        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
+        $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)));

        $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();
@@ -276,16 +263,13 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase

    public function testDetermineMissingBearerInHeader()
    {
-        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
-
-        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
+        $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)));

        $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();
--- a/tests/Stubs/.gitattributes
+++ b/tests/Stubs/.gitattributes
@@ -0,0 +1 @@
+private.key.crlf text eol=crlf
--- 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)
--- a/tests/Stubs/private.key.crlf
+++ b/tests/Stubs/private.key.crlf
@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
--- a/tests/Utils/CryptKeyTest.php
+++ b/tests/Utils/CryptKeyTest.php
@@ -3,8 +3,9 @@
 namespace LeagueTests\Utils;

 use League\OAuth2\Server\CryptKey;
+use PHPUnit\Framework\TestCase;

-class CryptKeyTest extends \PHPUnit_Framework_TestCase
+class CryptKeyTest extends TestCase
 {
    /**
     * @expectedException \LogicException
@@ -16,7 +17,7 @@ class CryptKeyTest extends \PHPUnit_Framework_TestCase

    public function testKeyCreation()
    {
-        $keyFile = __DIR__ . '/Stubs/public.key';
+        $keyFile = __DIR__ . '/../Stubs/public.key';
        $key = new CryptKey($keyFile, 'secret');

        $this->assertEquals('file://' . $keyFile, $key->getKeyPath());
@@ -25,7 +26,15 @@ class CryptKeyTest extends \PHPUnit_Framework_TestCase

    public function testKeyFileCreation()
    {
-        $keyContent = file_get_contents(__DIR__ . '/Stubs/public.key');
+        $keyContent = file_get_contents(__DIR__ . '/../Stubs/public.key');
+        $key = new CryptKey($keyContent);
+
+        $this->assertEquals(
+            'file://' . sys_get_temp_dir() . '/' . sha1($keyContent) . '.key',
+            $key->getKeyPath()
+        );
+
+        $keyContent = file_get_contents(__DIR__ . '/../Stubs/private.key.crlf');
        $key = new CryptKey($keyContent);

        $this->assertEquals(
--- a/tests/Utils/CryptTraitTest.php
+++ b/tests/Utils/CryptTraitTest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace LeagueTests\Utils;
+
+use LeagueTests\Stubs\CryptTraitStub;
+use PHPUnit\Framework\TestCase;
+
+class CryptTraitTest extends TestCase
+{
+    /**
+     * @var \LeagueTests\Stubs\CryptTraitStub
+     */
+    protected $cryptStub;
+
+    public function setUp()
+    {
+        $this->cryptStub = new CryptTraitStub;
+    }
+
+    public function testEncryptDecrypt()
+    {
+        $payload = 'alex loves whisky';
+        $encrypted = $this->cryptStub->doEncrypt($payload);
+        $plainText = $this->cryptStub->doDecrypt($encrypted);
+
+        $this->assertNotEquals($payload, $encrypted);
+        $this->assertEquals($payload, $plainText);
+    }
+}