diff --git a/src/OAuth2/Controller/AuthorizeController.php b/src/OAuth2/Controller/AuthorizeController.php
index 4bafb1d24..b2e12bb5d 100644
--- a/src/OAuth2/Controller/AuthorizeController.php
+++ b/src/OAuth2/Controller/AuthorizeController.php
@@ -87,6 +87,7 @@ public function __construct(ClientInterface $clientStorage, array $responseTypes
             'enforce_state'  => true,
             'require_exact_redirect_uri' => true,
             'redirect_status_code' => 302,
+            'enforce_pkce' => false,
         ), $config);
 
         if (is_null($scopeUtil)) {
diff --git a/src/OAuth2/GrantType/AuthorizationCode.php b/src/OAuth2/GrantType/AuthorizationCode.php
index 784f6b3a3..5bcb4f253 100644
--- a/src/OAuth2/GrantType/AuthorizationCode.php
+++ b/src/OAuth2/GrantType/AuthorizationCode.php
@@ -84,6 +84,41 @@ public function validateRequest(RequestInterface $request, ResponseInterface $re
             return false;
         }
 
+        if (isset($authCode['code_challenge']) && $authCode['code_challenge']) {
+            if (!($code_verifier = $request->request('code_verifier'))) {
+                $response->setError(400, 'code_verifier_missing', "The PKCE code verifier parameter is required.");
+
+                return false;
+            }
+            // Validate code_verifier according to RFC-7636
+            // @see: https://tools.ietf.org/html/rfc7636#section-4.1
+            if (preg_match('/^[A-Za-z0-9-._~]{43,128}$/', $code_verifier) !== 1) {
+                $response->setError(400, 'code_verifier_invalid', "The PKCE code verifier parameter is invalid.");
+
+                return false;
+            }
+            $code_verifier = $request->request('code_verifier');
+            switch ($authCode['code_challenge_method']) {
+                case 'S256':
+                    $code_verifier_hashed = strtr(rtrim(base64_encode(hash('sha256', $code_verifier, true)), '='), '+/', '-_');
+                    break;
+
+                case 'plain':
+                    $code_verifier_hashed = $code_verifier;
+                    break;
+
+                default:
+                    $response->setError(400, 'code_challenge_method_invalid', "Unknown PKCE code challenge method.");
+
+                return FALSE;
+            }
+            if ($code_verifier_hashed !== $authCode['code_challenge']) {
+                $response->setError(400, 'code_verifier_mismatch', "The PKCE code verifier parameter does not match the code challenge.");
+
+                return FALSE;
+            }
+        }
+
         if (!isset($authCode['code'])) {
             $authCode['code'] = $code; // used to expire the code after the access token is granted
         }
diff --git a/src/OAuth2/OpenID/Controller/AuthorizeController.php b/src/OAuth2/OpenID/Controller/AuthorizeController.php
index 54c5f9a63..52e183bb3 100644
--- a/src/OAuth2/OpenID/Controller/AuthorizeController.php
+++ b/src/OAuth2/OpenID/Controller/AuthorizeController.php
@@ -16,6 +16,16 @@ class AuthorizeController extends BaseAuthorizeController implements AuthorizeCo
      */
     private $nonce;
 
+    /**
+     * @var mixed
+     */
+    protected $code_challenge;
+
+    /**
+     * @var mixed
+     */
+    protected $code_challenge_method;
+
     /**
      * Set not authorized response
      *
@@ -65,6 +75,10 @@ protected function buildAuthorizeParameters($request, $response, $user_id)
         // add the nonce to return with the redirect URI
         $params['nonce'] = $this->nonce;
 
+        // Add PKCE code challenge.
+        $params['code_challenge'] = $this->code_challenge;
+        $params['code_challenge_method'] = $this->code_challenge_method;
+
         return $params;
     }
 
@@ -90,6 +104,32 @@ public function validateAuthorizeRequest(RequestInterface $request, ResponseInte
 
         $this->nonce = $nonce;
 
+        $code_challenge = $request->query('code_challenge');
+        $code_challenge_method = $request->query('code_challenge_method');
+
+        if ($this->config['enforce_pkce']) {
+            if (!$code_challenge) {
+                $response->setError(400, 'missing_code_challenge', 'This application requires you provide a PKCE code challenge');
+
+                return false;
+            }
+
+            if (preg_match('/^[A-Za-z0-9-._~]{43,128}$/', $code_challenge) !== 1) {
+            $response->setError(400, 'invalid_code_challenge', 'The PKCE code challenge supplied is invalid');
+
+            return false;
+          }
+
+            if (!in_array($code_challenge_method, array('plain', 'S256'), true)) {
+                $response->setError(400, 'missing_code_challenge_method', 'This application requires you specify a PKCE code challenge method');
+
+                return false;
+            }
+        }
+
+        $this->code_challenge = $code_challenge;
+        $this->code_challenge_method = $code_challenge_method;
+
         return true;
     }
 
diff --git a/src/OAuth2/OpenID/ResponseType/AuthorizationCode.php b/src/OAuth2/OpenID/ResponseType/AuthorizationCode.php
index b8ad41ffb..19e04104d 100644
--- a/src/OAuth2/OpenID/ResponseType/AuthorizationCode.php
+++ b/src/OAuth2/OpenID/ResponseType/AuthorizationCode.php
@@ -31,9 +31,9 @@ public function getAuthorizeResponse($params, $user_id = null)
         // build the URL to redirect to
         $result = array('query' => array());
 
-        $params += array('scope' => null, 'state' => null, 'id_token' => null);
+        $params += array('scope' => null, 'state' => null, 'id_token' => null, 'code_challenge' => null, 'code_challenge_method' => null);
 
-        $result['query']['code'] = $this->createAuthorizationCode($params['client_id'], $user_id, $params['redirect_uri'], $params['scope'], $params['id_token']);
+        $result['query']['code'] = $this->createAuthorizationCode($params['client_id'], $user_id, $params['redirect_uri'], $params['scope'], $params['id_token'], $params['code_challenge'], $params['code_challenge_method']);
 
         if (isset($params['state'])) {
             $result['query']['state'] = $params['state'];
@@ -56,10 +56,10 @@ public function getAuthorizeResponse($params, $user_id = null)
      * @see http://tools.ietf.org/html/rfc6749#section-4
      * @ingroup oauth2_section_4
      */
-    public function createAuthorizationCode($client_id, $user_id, $redirect_uri, $scope = null, $id_token = null)
+    public function createAuthorizationCode($client_id, $user_id, $redirect_uri, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         $code = $this->generateAuthorizationCode();
-        $this->storage->setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, time() + $this->config['auth_code_lifetime'], $scope, $id_token);
+        $this->storage->setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, time() + $this->config['auth_code_lifetime'], $scope, $id_token, $code_challenge, $code_challenge_method);
 
         return $code;
     }
diff --git a/src/OAuth2/OpenID/Storage/AuthorizationCodeInterface.php b/src/OAuth2/OpenID/Storage/AuthorizationCodeInterface.php
index 446cec928..8e0988ff4 100644
--- a/src/OAuth2/OpenID/Storage/AuthorizationCodeInterface.php
+++ b/src/OAuth2/OpenID/Storage/AuthorizationCodeInterface.php
@@ -33,5 +33,5 @@ interface AuthorizationCodeInterface extends BaseAuthorizationCodeInterface
      *
      * @ingroup oauth2_section_4
      */
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null);
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null);
 }
diff --git a/src/OAuth2/ResponseType/AuthorizationCode.php b/src/OAuth2/ResponseType/AuthorizationCode.php
index b92c73cda..7b33f7ce1 100644
--- a/src/OAuth2/ResponseType/AuthorizationCode.php
+++ b/src/OAuth2/ResponseType/AuthorizationCode.php
@@ -26,9 +26,9 @@ public function getAuthorizeResponse($params, $user_id = null)
         // build the URL to redirect to
         $result = array('query' => array());
 
-        $params += array('scope' => null, 'state' => null);
+        $params += array('scope' => null, 'state' => null, 'code_challenge' => null, 'code_challenge_method' => null);
 
-        $result['query']['code'] = $this->createAuthorizationCode($params['client_id'], $user_id, $params['redirect_uri'], $params['scope']);
+        $result['query']['code'] = $this->createAuthorizationCode($params['client_id'], $user_id, $params['redirect_uri'], $params['scope'], $params['code_challenge'], $params['code_challenge_method']);
 
         if (isset($params['state'])) {
             $result['query']['state'] = $params['state'];
@@ -53,10 +53,10 @@ public function getAuthorizeResponse($params, $user_id = null)
      * @see http://tools.ietf.org/html/rfc6749#section-4
      * @ingroup oauth2_section_4
      */
-    public function createAuthorizationCode($client_id, $user_id, $redirect_uri, $scope = null)
+    public function createAuthorizationCode($client_id, $user_id, $redirect_uri, $scope = null, $code_challenge = null, $code_challenge_method = null)
     {
         $code = $this->generateAuthorizationCode();
-        $this->storage->setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, time() + $this->config['auth_code_lifetime'], $scope);
+        $this->storage->setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, time() + $this->config['auth_code_lifetime'], $scope, $code_challenge, $code_challenge_method);
 
         return $code;
     }
diff --git a/src/OAuth2/Server.php b/src/OAuth2/Server.php
index cf040c2bc..1fbc6666d 100644
--- a/src/OAuth2/Server.php
+++ b/src/OAuth2/Server.php
@@ -172,6 +172,7 @@ public function __construct($storage = array(), array $config = array(), array $
             'enforce_state'            => true,
             'require_exact_redirect_uri' => true,
             'allow_implicit'           => false,
+            'enforce_pkce'             => false,
             'allow_credentials_in_request_body' => true,
             'allow_public_clients'     => true,
             'always_issue_new_refresh_token' => false,
@@ -577,7 +578,7 @@ protected function createDefaultAuthorizeController()
             }
         }
 
-        $config = array_intersect_key($this->config, array_flip(explode(' ', 'allow_implicit enforce_state require_exact_redirect_uri')));
+        $config = array_intersect_key($this->config, array_flip(explode(' ', 'allow_implicit enforce_state require_exact_redirect_uri enforce_pkce')));
 
         if ($this->config['use_openid_connect']) {
             return new OpenIDAuthorizeController($this->storages['client'], $this->responseTypes, $config, $this->getScopeUtil());
diff --git a/src/OAuth2/Storage/Cassandra.php b/src/OAuth2/Storage/Cassandra.php
index e60e9d3ad..3a138bb52 100644
--- a/src/OAuth2/Storage/Cassandra.php
+++ b/src/OAuth2/Storage/Cassandra.php
@@ -191,11 +191,11 @@ public function getAuthorizationCode($code)
      * @param string $id_token
      * @return bool
      */
-    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         return $this->setValue(
             $this->config['code_key'] . $authorization_code,
-            compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token'),
+            compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method'),
             $expires
         );
     }
diff --git a/src/OAuth2/Storage/CouchbaseDB.php b/src/OAuth2/Storage/CouchbaseDB.php
index 9e8148b6b..5c0d7b423 100755
--- a/src/OAuth2/Storage/CouchbaseDB.php
+++ b/src/OAuth2/Storage/CouchbaseDB.php
@@ -173,7 +173,7 @@ public function getAuthorizationCode($code)
         return is_null($code) ? false : $code;
     }
 
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
@@ -185,6 +185,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                 'expires' => $expires,
                 'scope' => $scope,
                 'id_token' => $id_token,
+                'code_challenge' => $code_challenge,
+                'code_challenge_method' => $code_challenge_method,
             ));
         } else {
             $this->setObjectByType('code_table',$code,array(
@@ -195,6 +197,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                 'expires' => $expires,
                 'scope' => $scope,
                 'id_token' => $id_token,
+                'code_challenge' => $code_challenge,
+                'code_challenge_method' => $code_challenge_method,
             ));
         }
 
diff --git a/src/OAuth2/Storage/DynamoDB.php b/src/OAuth2/Storage/DynamoDB.php
index a54cb3712..713189d23 100644
--- a/src/OAuth2/Storage/DynamoDB.php
+++ b/src/OAuth2/Storage/DynamoDB.php
@@ -213,12 +213,12 @@ public function getAuthorizationCode($code)
 
     }
 
-    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // convert expires to datestring
         $expires = date('Y-m-d H:i:s', $expires);
 
-        $clientData = compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'id_token', 'scope');
+        $clientData = compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method');
         $clientData = array_filter($clientData, 'self::isNotEmpty');
 
         $result = $this->client->putItem(array(
diff --git a/src/OAuth2/Storage/Memory.php b/src/OAuth2/Storage/Memory.php
index 2c60b71ce..c33bd0ebb 100644
--- a/src/OAuth2/Storage/Memory.php
+++ b/src/OAuth2/Storage/Memory.php
@@ -74,9 +74,9 @@ public function getAuthorizationCode($code)
         ), $this->authorizationCodes[$code]);
     }
 
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
-        $this->authorizationCodes[$code] = compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token');
+        $this->authorizationCodes[$code] = compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method');
 
         return true;
     }
diff --git a/src/OAuth2/Storage/Mongo.php b/src/OAuth2/Storage/Mongo.php
index eea06e315..92f93d5b2 100644
--- a/src/OAuth2/Storage/Mongo.php
+++ b/src/OAuth2/Storage/Mongo.php
@@ -179,7 +179,7 @@ public function getAuthorizationCode($code)
         return is_null($code) ? false : $code;
     }
 
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
@@ -192,6 +192,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                     'expires' => $expires,
                     'scope' => $scope,
                     'id_token' => $id_token,
+                    'code_challenge' => $code_challenge,
+                    'code_challenge_method' => $code_challenge_method,
                 ))
             );
         } else {
@@ -203,6 +205,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                 'expires' => $expires,
                 'scope' => $scope,
                 'id_token' => $id_token,
+                'code_challenge' => $code_challenge,
+                'code_challenge_method' => $code_challenge_method,
             );
             $this->collection('code_table')->insert($token);
         }
diff --git a/src/OAuth2/Storage/MongoDB.php b/src/OAuth2/Storage/MongoDB.php
index 64f740fc1..ef302ae57 100644
--- a/src/OAuth2/Storage/MongoDB.php
+++ b/src/OAuth2/Storage/MongoDB.php
@@ -167,7 +167,7 @@ public function getAuthorizationCode($code)
         return is_null($code) ? false : $code;
     }
 
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
@@ -180,6 +180,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                     'expires' => $expires,
                     'scope' => $scope,
                     'id_token' => $id_token,
+                    'code_challenge' => $code_challenge,
+                    'code_challenge_method' => $code_challenge_method,
                 ))
             );
             return $result->getMatchedCount() > 0;
@@ -192,6 +194,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
             'expires' => $expires,
             'scope' => $scope,
             'id_token' => $id_token,
+            'code_challenge' => $code_challenge,
+            'code_challenge_method' => $code_challenge_method,
         );
         $result = $this->collection('code_table')->insertOne($token);
         return $result->getInsertedCount() > 0;
diff --git a/src/OAuth2/Storage/Pdo.php b/src/OAuth2/Storage/Pdo.php
index 074cee447..46c873359 100644
--- a/src/OAuth2/Storage/Pdo.php
+++ b/src/OAuth2/Storage/Pdo.php
@@ -247,7 +247,7 @@ public function getAuthorizationCode($code)
      * @param string $id_token
      * @return bool|mixed
      */
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         if (func_num_args() > 6) {
             // we are calling with an id token
@@ -259,12 +259,12 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
 
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
-            $stmt = $this->db->prepare($sql = sprintf('UPDATE %s SET client_id=:client_id, user_id=:user_id, redirect_uri=:redirect_uri, expires=:expires, scope=:scope where authorization_code=:code', $this->config['code_table']));
+            $stmt = $this->db->prepare($sql = sprintf('UPDATE %s SET client_id=:client_id, user_id=:user_id, redirect_uri=:redirect_uri, expires=:expires, scope=:scope, code_challenge=:code_challenge, code_challenge_method=:code_challenge_method where authorization_code=:code', $this->config['code_table']));
         } else {
-            $stmt = $this->db->prepare(sprintf('INSERT INTO %s (authorization_code, client_id, user_id, redirect_uri, expires, scope) VALUES (:code, :client_id, :user_id, :redirect_uri, :expires, :scope)', $this->config['code_table']));
+            $stmt = $this->db->prepare(sprintf('INSERT INTO %s (authorization_code, client_id, user_id, redirect_uri, expires, scope, code_challenge, code_challenge_method) VALUES (:code, :client_id, :user_id, :redirect_uri, :expires, :scope, :code_challenge, :code_challenge_method)', $this->config['code_table']));
         }
 
-        return $stmt->execute(compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope'));
+        return $stmt->execute(compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'code_challenge', 'code_challenge_method'));
     }
 
     /**
@@ -277,19 +277,19 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
      * @param string $id_token
      * @return bool
      */
-    private function setAuthorizationCodeWithIdToken($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    private function setAuthorizationCodeWithIdToken($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // convert expires to datestring
         $expires = date('Y-m-d H:i:s', $expires);
 
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
-            $stmt = $this->db->prepare($sql = sprintf('UPDATE %s SET client_id=:client_id, user_id=:user_id, redirect_uri=:redirect_uri, expires=:expires, scope=:scope, id_token =:id_token where authorization_code=:code', $this->config['code_table']));
+            $stmt = $this->db->prepare($sql = sprintf('UPDATE %s SET client_id=:client_id, user_id=:user_id, redirect_uri=:redirect_uri, expires=:expires, scope=:scope, id_token =:id_token, code_challenge=:code_challenge, code_challenge_method=:code_challenge_method where authorization_code=:code', $this->config['code_table']));
         } else {
-            $stmt = $this->db->prepare(sprintf('INSERT INTO %s (authorization_code, client_id, user_id, redirect_uri, expires, scope, id_token) VALUES (:code, :client_id, :user_id, :redirect_uri, :expires, :scope, :id_token)', $this->config['code_table']));
+            $stmt = $this->db->prepare(sprintf('INSERT INTO %s (authorization_code, client_id, user_id, redirect_uri, expires, scope, id_token, code_challenge, code_challenge_method) VALUES (:code, :client_id, :user_id, :redirect_uri, :expires, :scope, :id_token, :code_challenge, :code_challenge_method)', $this->config['code_table']));
         }
 
-        return $stmt->execute(compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token'));
+        return $stmt->execute(compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method'));
     }
 
     /**
@@ -676,6 +676,8 @@ public function getBuildSql($dbName = 'oauth2_server_php')
               expires             TIMESTAMP      NOT NULL,
               scope               VARCHAR(4000),
               id_token            VARCHAR(1000),
+              code_challenge        VARCHAR(1000),
+              code_challenge_method VARCHAR(20),
               PRIMARY KEY (authorization_code)
             );
 
diff --git a/src/OAuth2/Storage/Redis.php b/src/OAuth2/Storage/Redis.php
index e6294e22d..5a41dfc22 100644
--- a/src/OAuth2/Storage/Redis.php
+++ b/src/OAuth2/Storage/Redis.php
@@ -95,11 +95,11 @@ public function getAuthorizationCode($code)
         return $this->getValue($this->config['code_key'] . $code);
     }
 
-    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         return $this->setValue(
             $this->config['code_key'] . $authorization_code,
-            compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token'),
+            compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method'),
             $expires
         );
     }