diff --git a/src/AuthorizationValidators/BearerTokenValidator.php b/src/AuthorizationValidators/BearerTokenValidator.php
index 5dab2203..3c550e19 100644
--- a/src/AuthorizationValidators/BearerTokenValidator.php
+++ b/src/AuthorizationValidators/BearerTokenValidator.php
@@ -43,7 +43,7 @@ class BearerTokenValidator implements AuthorizationValidatorInterface
         try {
             // Attempt to parse and validate the JWT
             $token = (new Parser())->parse($jwt);
-            if ($token->verify(new Sha256(), $this->publicKeyPath) === false) {
+            if ($token->verify(new Sha256(), $this->publicKey->getKeyPath()) === false) {
                 throw OAuthServerException::accessDenied('Access token could not be verified');
             }
 
diff --git a/src/CryptKey.php b/src/CryptKey.php
new file mode 100644
index 00000000..4ea05264
--- /dev/null
+++ b/src/CryptKey.php
@@ -0,0 +1,62 @@
+<?php
+/**
+ * Cryptography key holder.
+ *
+ * @author      Julián Gutiérrez <juliangut@gmail.com>
+ * @copyright   Copyright (c) Alex Bilbie
+ * @license     http://mit-license.org/
+ *
+ * @link        https://github.com/thephpleague/oauth2-server
+ */
+namespace League\OAuth2\Server;
+
+class CryptKey
+{
+    /**
+     * @var string
+     */
+    protected $keyPath;
+
+    /**
+     * @var string
+     */
+    protected $passPhrase;
+
+    /**
+     * @param string      $keyPath
+     * @param null|string $passPhrase
+     */
+    public function __construct($keyPath, $passPhrase = null)
+    {
+        if (strpos($keyPath, 'file://') !== 0) {
+            $keyPath = 'file://' . $keyPath;
+        }
+
+        if (!file_exists($keyPath) || !is_readable($keyPath)) {
+            throw new \LogicException(sprintf('Key path "%s" does not exist or is not readable', $keyPath));
+        }
+
+        $this->keyPath = $keyPath;
+        $this->passPhrase = $passPhrase;
+    }
+
+    /**
+     * Retrieve key path.
+     *
+     * @return string
+     */
+    public function getKeyPath()
+    {
+        return $this->keyPath;
+    }
+
+    /**
+     * Retrieve key pass phrase.
+     *
+     * @return null|string
+     */
+    public function getPassPhrase()
+    {
+        return $this->passPhrase;
+    }
+}
diff --git a/src/CryptTrait.php b/src/CryptTrait.php
index 3c648b79..1075ea12 100644
--- a/src/CryptTrait.php
+++ b/src/CryptTrait.php
@@ -13,41 +13,33 @@ namespace League\OAuth2\Server;
 trait CryptTrait
 {
     /**
-     * @var string
+     * @var \League\OAuth2\Server\CryptKey
      */
-    protected $privateKeyPath;
+    protected $privateKey;
 
     /**
-     * @var string
+     * @var \League\OAuth2\Server\CryptKey
      */
-    protected $publicKeyPath;
+    protected $publicKey;
 
     /**
      * Set path to private key.
      *
-     * @param string $privateKeyPath
+     * @param \League\OAuth2\Server\CryptKey $privateKey
      */
-    public function setPrivateKeyPath($privateKeyPath)
+    public function setPrivateKey(CryptKey $privateKey)
     {
-        if (strpos($privateKeyPath, 'file://') !== 0) {
-            $privateKeyPath = 'file://' . $privateKeyPath;
-        }
-
-        $this->privateKeyPath = $privateKeyPath;
+        $this->privateKey = $privateKey;
     }
 
     /**
      * Set path to public key.
      *
-     * @param string $publicKeyPath
+     * @param \League\OAuth2\Server\CryptKey $publicKey
      */
-    public function setPublicKeyPath($publicKeyPath)
+    public function setPublicKey(CryptKey $publicKey)
     {
-        if (strpos($publicKeyPath, 'file://') !== 0) {
-            $publicKeyPath = 'file://' . $publicKeyPath;
-        }
-
-        $this->publicKeyPath = $publicKeyPath;
+        $this->publicKey = $publicKey;
     }
 
     /**
@@ -59,10 +51,12 @@ trait CryptTrait
      */
     protected function encrypt($unencryptedData)
     {
-        $privateKey = openssl_pkey_get_private($this->privateKeyPath);
+        $privateKey = openssl_pkey_get_private($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->privateKeyPath));
+            throw new \LogicException(
+                sprintf('Could not get details of private key: %s', $this->privateKey->getKeyPath())
+            );
         }
 
         $chunkSize = ceil($privateKeyDetails['bits'] / 8) - 11;
@@ -78,7 +72,7 @@ trait CryptTrait
             }
             $output .= $encrypted;
         }
-        openssl_free_key($privateKey);
+        openssl_pkey_free($privateKey);
 
         return base64_encode($output);
     }
@@ -94,10 +88,12 @@ trait CryptTrait
      */
     protected function decrypt($encryptedData)
     {
-        $publicKey = openssl_pkey_get_public($this->publicKeyPath);
+        $publicKey = openssl_pkey_get_public($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->publicKeyPath));
+            throw new \LogicException(
+                sprintf('Could not get details of public key: %s', $this->publicKey->getKeyPath())
+            );
         }
 
         $chunkSize = ceil($publicKeyDetails['bits'] / 8);
@@ -115,7 +111,7 @@ trait CryptTrait
             }
             $output .= $decrypted;
         }
-        openssl_free_key($publicKey);
+        openssl_pkey_free($publicKey);
 
         return $output;
     }
diff --git a/src/Entities/AccessTokenEntity.php b/src/Entities/AccessTokenEntity.php
index 5b4b34a1..34ae167e 100644
--- a/src/Entities/AccessTokenEntity.php
+++ b/src/Entities/AccessTokenEntity.php
@@ -5,6 +5,7 @@ namespace League\OAuth2\Server\Entities;
 use Lcobucci\JWT\Builder;
 use Lcobucci\JWT\Signer\Key;
 use Lcobucci\JWT\Signer\Rsa\Sha256;
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\Interfaces\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\Traits\EntityTrait;
 use League\OAuth2\Server\Entities\Traits\TokenEntityTrait;
@@ -16,11 +17,11 @@ class AccessTokenEntity implements AccessTokenEntityInterface
     /**
      * Generate a JWT from the access token
      *
-     * @param string $privateKeyPath
+     * @param \League\OAuth2\Server\CryptKey $privateKey
      *
      * @return string
      */
-    public function convertToJWT($privateKeyPath)
+    public function convertToJWT(CryptKey $privateKey)
     {
         return (new Builder())
             ->setAudience($this->getClient()->getIdentifier())
@@ -30,7 +31,7 @@ class AccessTokenEntity implements AccessTokenEntityInterface
             ->setExpiration($this->getExpiryDateTime()->getTimestamp())
             ->setSubject($this->getUserIdentifier())
             ->set('scopes', $this->getScopes())
-            ->sign(new Sha256(), new Key($privateKeyPath))
+            ->sign(new Sha256(), new Key($privateKey->getKeyPath(), $privateKey->getPassPhrase()))
             ->getToken();
     }
 }
diff --git a/src/Entities/Interfaces/AccessTokenEntityInterface.php b/src/Entities/Interfaces/AccessTokenEntityInterface.php
index 86ad1107..2b4c38a8 100644
--- a/src/Entities/Interfaces/AccessTokenEntityInterface.php
+++ b/src/Entities/Interfaces/AccessTokenEntityInterface.php
@@ -2,14 +2,16 @@
 
 namespace League\OAuth2\Server\Entities\Interfaces;
 
+use League\OAuth2\Server\CryptKey;
+
 interface AccessTokenEntityInterface extends TokenInterface
 {
     /**
      * Generate a JWT from the access token
      *
-     * @param string $privateKeyPath
+     * @param \League\OAuth2\Server\CryptKey $privateKey
      *
      * @return string
      */
-    public function convertToJWT($privateKeyPath);
+    public function convertToJWT(CryptKey $privateKey);
 }
diff --git a/src/Grant/GrantTypeInterface.php b/src/Grant/GrantTypeInterface.php
index cb60bf90..0e4ce62d 100644
--- a/src/Grant/GrantTypeInterface.php
+++ b/src/Grant/GrantTypeInterface.php
@@ -11,6 +11,7 @@
 namespace League\OAuth2\Server\Grant;
 
 use League\Event\EmitterAwareInterface;
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
 use League\OAuth2\Server\Repositories\ScopeRepositoryInterface;
@@ -89,14 +90,14 @@ interface GrantTypeInterface extends EmitterAwareInterface
     /**
      * Set the path to the private key.
      *
-     * @param string $privateKeyPath
+     * @param \League\OAuth2\Server\CryptKey $privateKey
      */
-    public function setPrivateKeyPath($privateKeyPath);
+    public function setPrivateKey(CryptKey $privateKey);
 
     /**
      * Set the path to the public key.
      *
-     * @param string $publicKeyPath
+     * @param \League\OAuth2\Server\CryptKey $publicKey
      */
-    public function setPublicKeyPath($publicKeyPath);
+    public function setPublicKey(CryptKey $publicKey);
 }
diff --git a/src/Grant/ImplicitGrant.php b/src/Grant/ImplicitGrant.php
index 11950a78..2fe4a455 100644
--- a/src/Grant/ImplicitGrant.php
+++ b/src/Grant/ImplicitGrant.php
@@ -197,7 +197,7 @@ class ImplicitGrant extends AbstractAuthorizeGrant
                 $scopes
             );
 
-            $redirectPayload['access_token'] = (string) $accessToken->convertToJWT($this->privateKeyPath);
+            $redirectPayload['access_token'] = (string) $accessToken->convertToJWT($this->privateKey);
             $redirectPayload['token_type'] = 'bearer';
             $redirectPayload['expires_in'] = time() - $accessToken->getExpiryDateTime()->getTimestamp();
 
diff --git a/src/ResponseTypes/BearerTokenResponse.php b/src/ResponseTypes/BearerTokenResponse.php
index 17675b88..7a77c699 100644
--- a/src/ResponseTypes/BearerTokenResponse.php
+++ b/src/ResponseTypes/BearerTokenResponse.php
@@ -22,7 +22,7 @@ class BearerTokenResponse extends AbstractResponseType
     {
         $expireDateTime = $this->accessToken->getExpiryDateTime()->getTimestamp();
 
-        $jwtAccessToken = $this->accessToken->convertToJWT($this->privateKeyPath);
+        $jwtAccessToken = $this->accessToken->convertToJWT($this->privateKey);
 
         $responseParams = [
             'token_type'   => 'Bearer',
diff --git a/src/Server.php b/src/Server.php
index e77a344b..e5573026 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -32,20 +32,20 @@ class Server implements EmitterAwareInterface
     protected $grantTypeAccessTokenTTL = [];
 
     /**
-     * @var string
+     * @var \League\OAuth2\Server\CryptKey
      */
-    protected $privateKeyPath;
+    protected $privateKey;
+
+    /**
+     * @var \League\OAuth2\Server\CryptKey
+     */
+    protected $publicKey;
 
     /**
      * @var ResponseTypeInterface
      */
     protected $responseType;
 
-    /**
-     * @var string
-     */
-    private $publicKeyPath;
-
     /**
      * @var \League\OAuth2\Server\Repositories\ClientRepositoryInterface
      */
@@ -72,8 +72,8 @@ class Server implements EmitterAwareInterface
      * @param \League\OAuth2\Server\Repositories\ClientRepositoryInterface                       $clientRepository
      * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface                  $accessTokenRepository
      * @param \League\OAuth2\Server\Repositories\ScopeRepositoryInterface                        $scopeRepository
-     * @param string                                                                             $privateKeyPath
-     * @param string                                                                             $publicKeyPath
+     * @param \League\OAuth2\Server\CryptKey|string                                              $privateKey
+     * @param \League\OAuth2\Server\CryptKey|string                                              $publicKey
      * @param null|\League\OAuth2\Server\ResponseTypes\ResponseTypeInterface                     $responseType
      * @param null|\League\OAuth2\Server\AuthorizationValidators\AuthorizationValidatorInterface $authorizationValidator
      */
@@ -81,16 +81,25 @@ class Server implements EmitterAwareInterface
         ClientRepositoryInterface $clientRepository,
         AccessTokenRepositoryInterface $accessTokenRepository,
         ScopeRepositoryInterface $scopeRepository,
-        $privateKeyPath,
-        $publicKeyPath,
+        $privateKey,
+        $publicKey,
         ResponseTypeInterface $responseType = null,
         AuthorizationValidatorInterface $authorizationValidator = null
     ) {
         $this->clientRepository = $clientRepository;
         $this->accessTokenRepository = $accessTokenRepository;
         $this->scopeRepository = $scopeRepository;
-        $this->privateKeyPath = $privateKeyPath;
-        $this->publicKeyPath = $publicKeyPath;
+
+        if (!$privateKey instanceof CryptKey) {
+            $privateKey = new CryptKey($privateKey);
+        }
+        $this->privateKey = $privateKey;
+
+        if (!$publicKey instanceof CryptKey) {
+            $publicKey = new CryptKey($publicKey);
+        }
+        $this->publicKey = $publicKey;
+
         $this->responseType = $responseType;
         $this->authorizationValidator = $authorizationValidator;
     }
@@ -106,8 +115,8 @@ class Server implements EmitterAwareInterface
         $grantType->setAccessTokenRepository($this->accessTokenRepository);
         $grantType->setClientRepository($this->clientRepository);
         $grantType->setScopeRepository($this->scopeRepository);
-        $grantType->setPrivateKeyPath($this->privateKeyPath);
-        $grantType->setPublicKeyPath($this->publicKeyPath);
+        $grantType->setPrivateKey($this->privateKey);
+        $grantType->setPublicKey($this->publicKey);
         $grantType->setEmitter($this->getEmitter());
 
         $this->enabledGrantTypes[$grantType->getIdentifier()] = $grantType;
@@ -118,8 +127,8 @@ class Server implements EmitterAwareInterface
     /**
      * Return an access token response.
      *
-     * @param \Psr\Http\Message\ServerRequestInterface|null $request
-     * @param \Psr\Http\Message\ResponseInterface|null      $response
+     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param \Psr\Http\Message\ResponseInterface      $response
      *
      * @throws \League\OAuth2\Server\Exception\OAuthServerException
      *
@@ -171,8 +180,7 @@ class Server implements EmitterAwareInterface
             $this->responseType = new BearerTokenResponse($this->accessTokenRepository);
         }
 
-        $this->responseType->setPublicKeyPath($this->publicKeyPath);
-        $this->responseType->setPrivateKeyPath($this->privateKeyPath);
+        $this->responseType->setPrivateKey($this->privateKey);
 
         return $this->responseType;
     }
@@ -186,8 +194,7 @@ class Server implements EmitterAwareInterface
             $this->authorizationValidator = new BearerTokenValidator($this->accessTokenRepository);
         }
 
-        $this->authorizationValidator->setPublicKeyPath($this->publicKeyPath);
-        $this->authorizationValidator->setPrivateKeyPath($this->privateKeyPath);
+        $this->authorizationValidator->setPublicKey($this->publicKey);
 
         return $this->authorizationValidator;
     }
diff --git a/tests/CryptTraitTest.php b/tests/CryptTraitTest.php
index fad2fdcf..364d712f 100644
--- a/tests/CryptTraitTest.php
+++ b/tests/CryptTraitTest.php
@@ -2,6 +2,7 @@
 
 namespace LeagueTests\Utils;
 
+use League\OAuth2\Server\CryptKey;
 use LeagueTests\Stubs\CryptTraitStub;
 
 class CryptTraitTest extends \PHPUnit_Framework_TestCase
@@ -31,7 +32,7 @@ class CryptTraitTest extends \PHPUnit_Framework_TestCase
      */
     public function testBadPrivateKey()
     {
-        $this->cryptStub->setPrivateKeyPath(__DIR__ . '/Stubs/public.key');
+        $this->cryptStub->setPrivateKey(new CryptKey(__DIR__ . '/Stubs/public.key'));
         $this->cryptStub->doEncrypt('');
     }
 
@@ -40,7 +41,7 @@ class CryptTraitTest extends \PHPUnit_Framework_TestCase
      */
     public function testBadPublicKey()
     {
-        $this->cryptStub->setPublicKeyPath(__DIR__ . '/Stubs/private.key');
+        $this->cryptStub->setPublicKey(new CryptKey(__DIR__ . '/Stubs/private.key'));
         $this->cryptStub->doDecrypt('');
     }
 }
diff --git a/tests/Grant/AbstractGrantTest.php b/tests/Grant/AbstractGrantTest.php
index cdde8764..db281430 100644
--- a/tests/Grant/AbstractGrantTest.php
+++ b/tests/Grant/AbstractGrantTest.php
@@ -3,6 +3,7 @@
 namespace LeagueTests\Grant;
 
 use League\Event\Emitter;
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\AccessTokenEntity;
 use League\OAuth2\Server\Entities\Interfaces\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\Interfaces\AuthCodeEntityInterface;
@@ -23,8 +24,8 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
     {
         /** @var AbstractGrant $grantMock */
         $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
-        $grantMock->setPrivateKeyPath('./private.key');
-        $grantMock->setPublicKeyPath('./public.key');
+        $grantMock->setPrivateKey(new CryptKey(__DIR__ . '/../Stubs/private.key'));
+        $grantMock->setPublicKey(new CryptKey(__DIR__ . '/../Stubs/public.key'));
         $grantMock->setEmitter(new Emitter());
     }
 
diff --git a/tests/Grant/AuthCodeGrantTest.php b/tests/Grant/AuthCodeGrantTest.php
index 1dfb6974..6fe74782 100644
--- a/tests/Grant/AuthCodeGrantTest.php
+++ b/tests/Grant/AuthCodeGrantTest.php
@@ -2,6 +2,7 @@
 
 namespace LeagueTests\Grant;
 
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\Interfaces\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\Interfaces\RefreshTokenEntityInterface;
 use League\OAuth2\Server\Exception\OAuthServerException;
@@ -99,8 +100,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -161,8 +162,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         );
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -214,8 +215,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -260,8 +261,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -312,8 +313,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -370,8 +371,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -426,8 +427,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -483,8 +484,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         );
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -542,8 +543,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         );
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -607,8 +608,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setScopeRepository($scopeRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [],
@@ -665,8 +666,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [],
@@ -711,8 +712,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [],
@@ -762,8 +763,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [],
@@ -831,8 +832,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [],
@@ -897,8 +898,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [],
@@ -963,8 +964,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [],
diff --git a/tests/Grant/ImplicitGrantTest.php b/tests/Grant/ImplicitGrantTest.php
index 06525b9c..100b97aa 100644
--- a/tests/Grant/ImplicitGrantTest.php
+++ b/tests/Grant/ImplicitGrantTest.php
@@ -2,6 +2,7 @@
 
 namespace LeagueTests\Grant;
 
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Grant\ImplicitGrant;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
@@ -77,8 +78,8 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -115,8 +116,8 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
     public function testRespondToAuthorizationRequestMissingClientId()
     {
         $grant = new ImplicitGrant($this->getMock(UserRepositoryInterface::class));
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -152,8 +153,8 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
 
         $grant = new ImplicitGrant($this->getMock(UserRepositoryInterface::class));
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -199,8 +200,8 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
 
         $grant = new ImplicitGrant($this->getMock(UserRepositoryInterface::class));
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -252,8 +253,8 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
 
         $grant = new ImplicitGrant($this->getMock(UserRepositoryInterface::class));
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -299,8 +300,8 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
         $grant = new ImplicitGrant($this->getMock(UserRepositoryInterface::class));
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -350,8 +351,8 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
         $grant = new ImplicitGrant($this->getMock(UserRepositoryInterface::class));
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
@@ -401,8 +402,8 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
 
         $grant = new ImplicitGrant($this->getMock(UserRepositoryInterface::class));
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [
diff --git a/tests/Grant/RefreshTokenGrantTest.php b/tests/Grant/RefreshTokenGrantTest.php
index 719b28c3..d48a5af2 100644
--- a/tests/Grant/RefreshTokenGrantTest.php
+++ b/tests/Grant/RefreshTokenGrantTest.php
@@ -2,6 +2,7 @@
 
 namespace LeagueTests\Grant;
 
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\Interfaces\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\Interfaces\RefreshTokenEntityInterface;
 use League\OAuth2\Server\Grant\RefreshTokenGrant;
@@ -61,8 +62,8 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setScopeRepository($scopeRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $oldRefreshToken = $this->cryptStub->doEncrypt(
             json_encode(
@@ -116,8 +117,8 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $oldRefreshToken = $this->cryptStub->doEncrypt(
             json_encode(
@@ -176,8 +177,8 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
         $grant->setScopeRepository($scopeRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $oldRefreshToken = $this->cryptStub->doEncrypt(
             json_encode(
@@ -224,8 +225,8 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
         $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $serverRequest = new ServerRequest();
         $serverRequest = $serverRequest->withParsedBody(
@@ -257,8 +258,8 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
         $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $oldRefreshToken = 'foobar';
 
@@ -297,8 +298,8 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
         $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $oldRefreshToken = $this->cryptStub->doEncrypt(
             json_encode(
@@ -344,8 +345,8 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
         $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $oldRefreshToken = $this->cryptStub->doEncrypt(
             json_encode(
@@ -392,8 +393,8 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
         $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
         $grant->setClientRepository($clientRepositoryMock);
         $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
-        $grant->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $oldRefreshToken = $this->cryptStub->doEncrypt(
             json_encode(
diff --git a/tests/Middleware/AuthenticationServerMiddlewareTest.php b/tests/Middleware/AuthenticationServerMiddlewareTest.php
index 4acd5c89..bfed2651 100644
--- a/tests/Middleware/AuthenticationServerMiddlewareTest.php
+++ b/tests/Middleware/AuthenticationServerMiddlewareTest.php
@@ -27,8 +27,8 @@ class AuthenticationServerMiddlewareTest extends \PHPUnit_Framework_TestCase
             $clientRepository,
             $this->getMock(AccessTokenRepositoryInterface::class),
             $scopeRepositoryMock,
-            '',
-            '',
+            'file://' . __DIR__ . '/../Stubs/private.key',
+            'file://' . __DIR__ . '/../Stubs/public.key',
             new StubResponseType()
         );
 
@@ -60,8 +60,8 @@ class AuthenticationServerMiddlewareTest extends \PHPUnit_Framework_TestCase
             $clientRepository,
             $this->getMock(AccessTokenRepositoryInterface::class),
             $this->getMock(ScopeRepositoryInterface::class),
-            '',
-            '',
+            'file://' . __DIR__ . '/../Stubs/private.key',
+            'file://' . __DIR__ . '/../Stubs/public.key',
             new StubResponseType()
         );
 
diff --git a/tests/Middleware/ResourceServerMiddlewareTest.php b/tests/Middleware/ResourceServerMiddlewareTest.php
index 960113db..bb3f7ab7 100644
--- a/tests/Middleware/ResourceServerMiddlewareTest.php
+++ b/tests/Middleware/ResourceServerMiddlewareTest.php
@@ -2,6 +2,7 @@
 
 namespace LeagueTests\Middleware;
 
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\AccessTokenEntity;
 use League\OAuth2\Server\Middleware\ResourceServerMiddleware;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
@@ -37,7 +38,7 @@ class ResourceServerMiddlewareTest extends \PHPUnit_Framework_TestCase
         $accessToken->setExpiryDateTime((new \DateTime())->add(new \DateInterval('PT1H')));
         $accessToken->setClient($client);
 
-        $token = $accessToken->convertToJWT('file://' . __DIR__ . '/../Stubs/private.key');
+        $token = $accessToken->convertToJWT(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest();
         $request = $request->withHeader('authorization', sprintf('Bearer %s', $token));
@@ -64,8 +65,8 @@ class ResourceServerMiddlewareTest extends \PHPUnit_Framework_TestCase
             $clientRepository,
             $this->getMock(AccessTokenRepositoryInterface::class),
             $this->getMock(ScopeRepositoryInterface::class),
-            '',
-            '',
+            'file://' . __DIR__ . '/../Stubs/private.key',
+            'file://' . __DIR__ . '/../Stubs/public.key',
             new StubResponseType()
         );
 
diff --git a/tests/ResponseTypes/BearerResponseTypeTest.php b/tests/ResponseTypes/BearerResponseTypeTest.php
index a8b62f0e..3fb11168 100644
--- a/tests/ResponseTypes/BearerResponseTypeTest.php
+++ b/tests/ResponseTypes/BearerResponseTypeTest.php
@@ -3,6 +3,7 @@
 namespace LeagueTests\ResponseTypes;
 
 use League\OAuth2\Server\AuthorizationValidators\BearerTokenValidator;
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\AccessTokenEntity;
 use League\OAuth2\Server\Entities\RefreshTokenEntity;
 use League\OAuth2\Server\Exception\OAuthServerException;
@@ -21,8 +22,8 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
         $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
 
         $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
-        $responseType->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
-        $responseType->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
+        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
 
         $client = new ClientEntity();
         $client->setIdentifier('clientName');
@@ -66,8 +67,8 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
         $accessTokenRepositoryMock->method('isAccessTokenRevoked')->willReturn(false);
 
         $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
-        $responseType->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
-        $responseType->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
+        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
 
         $client = new ClientEntity();
         $client->setIdentifier('clientName');
@@ -90,8 +91,8 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
         $json = json_decode((string) $response->getBody());
 
         $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
-        $authorizationValidator->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
-        $authorizationValidator->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
+        $authorizationValidator->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
 
         $request = new ServerRequest();
         $request = $request->withHeader('authorization', sprintf('Bearer %s', $json->access_token));
@@ -110,8 +111,8 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
         $accessTokenRepositoryMock->method('isAccessTokenRevoked')->willReturn(false);
 
         $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
-        $responseType->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
-        $responseType->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
+        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
 
         $client = new ClientEntity();
         $client->setIdentifier('clientName');
@@ -134,8 +135,8 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
         $json = json_decode((string) $response->getBody());
 
         $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
-        $authorizationValidator->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
-        $authorizationValidator->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
+        $authorizationValidator->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
 
         $request = new ServerRequest();
         $request = $request->withHeader('authorization', sprintf('Bearer %s', $json->access_token . 'foo'));
@@ -156,8 +157,8 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
         $accessTokenRepositoryMock->method('isAccessTokenRevoked')->willReturn(true);
 
         $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
-        $responseType->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
-        $responseType->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
+        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
 
         $client = new ClientEntity();
         $client->setIdentifier('clientName');
@@ -180,8 +181,8 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
         $json = json_decode((string) $response->getBody());
 
         $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
-        $authorizationValidator->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
-        $authorizationValidator->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
+        $authorizationValidator->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
 
         $request = new ServerRequest();
         $request = $request->withHeader('authorization', sprintf('Bearer %s', $json->access_token));
@@ -201,12 +202,12 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
         $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
 
         $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
-        $responseType->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
-        $responseType->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
+        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
 
         $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
-        $authorizationValidator->setPrivateKeyPath('file://' . __DIR__ . '/../Stubs/private.key');
-        $authorizationValidator->setPublicKeyPath('file://' . __DIR__ . '/../Stubs/public.key');
+        $authorizationValidator->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
 
         $request = new ServerRequest();
         $request = $request->withHeader('authorization', 'Bearer blah');
diff --git a/tests/ServerTest.php b/tests/ServerTest.php
index f61818cf..d3c693d6 100644
--- a/tests/ServerTest.php
+++ b/tests/ServerTest.php
@@ -28,8 +28,8 @@ class ServerTest extends \PHPUnit_Framework_TestCase
             $this->getMock(ClientRepositoryInterface::class),
             $this->getMock(AccessTokenRepositoryInterface::class),
             $this->getMock(ScopeRepositoryInterface::class),
-            '',
-            '',
+            'file://' . __DIR__ . '/Stubs/private.key',
+            'file://' . __DIR__ . '/Stubs/public.key',
             new StubResponseType()
         );
 
@@ -55,8 +55,8 @@ class ServerTest extends \PHPUnit_Framework_TestCase
             $clientRepository,
             $this->getMock(AccessTokenRepositoryInterface::class),
             $scopeRepositoryMock,
-            '',
-            '',
+            'file://' . __DIR__ . '/Stubs/private.key',
+            'file://' . __DIR__ . '/Stubs/public.key',
             new StubResponseType()
         );
 
@@ -125,8 +125,8 @@ class ServerTest extends \PHPUnit_Framework_TestCase
             $clientRepository,
             $this->getMock(AccessTokenRepositoryInterface::class),
             $this->getMock(ScopeRepositoryInterface::class),
-            '',
-            ''
+            'file://' . __DIR__ . '/Stubs/private.key',
+            'file://' . __DIR__ . '/Stubs/public.key'
         );
 
         $abstractGrantReflection = new \ReflectionClass($server);
@@ -144,8 +144,8 @@ class ServerTest extends \PHPUnit_Framework_TestCase
             $clientRepository,
             $this->getMock(AccessTokenRepositoryInterface::class),
             $this->getMock(ScopeRepositoryInterface::class),
-            '',
-            ''
+            'file://' . __DIR__ . '/Stubs/private.key',
+            'file://' . __DIR__ . '/Stubs/public.key'
         );
 
         try {
diff --git a/tests/Stubs/CryptTraitStub.php b/tests/Stubs/CryptTraitStub.php
index 583a851c..2414c199 100644
--- a/tests/Stubs/CryptTraitStub.php
+++ b/tests/Stubs/CryptTraitStub.php
@@ -2,6 +2,7 @@
 
 namespace LeagueTests\Stubs;
 
+use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\CryptTrait;
 
 class CryptTraitStub
@@ -10,8 +11,8 @@ class CryptTraitStub
 
     public function __construct()
     {
-        $this->setPrivateKeyPath('file://' . __DIR__ . '/private.key');
-        $this->setPublicKeyPath('file://' . __DIR__ . '/public.key');
+        $this->setPrivateKey(new CryptKey('file://' . __DIR__ . '/private.key'));
+        $this->setPublicKey(new CryptKey('file://' . __DIR__ . '/public.key'));
     }
 
     public function doEncrypt($unencryptedData)