diff --git a/src/CsrfMiddleware.php b/src/CsrfMiddleware.php
index 6d5c35f..467712c 100644
--- a/src/CsrfMiddleware.php
+++ b/src/CsrfMiddleware.php
@@ -28,8 +28,18 @@ final class CsrfMiddleware implements MiddlewareInterface
     private string $parameterName = self::PARAMETER_NAME;
     private string $headerName = self::HEADER_NAME;
 
-    public function __construct(private ResponseFactoryInterface $responseFactory, private CsrfTokenInterface $token, private ?RequestHandlerInterface $failureHandler = null)
-    {
+    private ResponseFactoryInterface $responseFactory;
+    private CsrfTokenInterface $token;
+    private ?RequestHandlerInterface $failureHandler;
+
+    public function __construct(
+        ResponseFactoryInterface $responseFactory,
+        CsrfTokenInterface $token,
+        RequestHandlerInterface $failureHandler = null
+    ) {
+        $this->responseFactory = $responseFactory;
+        $this->token = $token;
+        $this->failureHandler = $failureHandler;
     }
 
     public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
diff --git a/src/Hmac/HmacCsrfToken.php b/src/Hmac/HmacCsrfToken.php
index b695767..b7aeabc 100644
--- a/src/Hmac/HmacCsrfToken.php
+++ b/src/Hmac/HmacCsrfToken.php
@@ -24,21 +24,29 @@
  */
 final class HmacCsrfToken implements CsrfTokenInterface
 {
+    private CsrfTokenIdentityGeneratorInterface $identityGenerator;
     private Mac $mac;
 
+    /**
+     * @var string Shared secret key used to generate the hash.
+     */
+    private string $secretKey;
+
+    /**
+     * @var int|null Number of seconds that the token is valid for.
+     */
+    private ?int $lifetime;
+
     public function __construct(
-        private CsrfTokenIdentityGeneratorInterface $identityGenerator,
-        /**
-         * @var string Shared secret key used to generate the hash.
-         */
-        private string $secretKey,
+        CsrfTokenIdentityGeneratorInterface $identityGenerator,
+        string $secretKey,
         string $algorithm = 'sha256',
-        /**
-         * @var int|null Number of seconds that the token is valid for.
-         */
-        private ?int $lifetime = null
+        ?int $lifetime = null
     ) {
+        $this->identityGenerator = $identityGenerator;
         $this->mac = new Mac($algorithm);
+        $this->secretKey = $secretKey;
+        $this->lifetime = $lifetime;
     }
 
     public function getValue(): string
@@ -83,7 +91,7 @@ private function extractData(string $token): ?array
                 $this->secretKey,
                 true
             );
-        } catch (DataIsTamperedException) {
+        } catch (DataIsTamperedException $e) {
             return null;
         }
 
diff --git a/src/Hmac/IdentityGenerator/SessionCsrfTokenIdentityGenerator.php b/src/Hmac/IdentityGenerator/SessionCsrfTokenIdentityGenerator.php
index 4223f31..cfd240f 100644
--- a/src/Hmac/IdentityGenerator/SessionCsrfTokenIdentityGenerator.php
+++ b/src/Hmac/IdentityGenerator/SessionCsrfTokenIdentityGenerator.php
@@ -11,8 +11,11 @@
  */
 final class SessionCsrfTokenIdentityGenerator implements CsrfTokenIdentityGeneratorInterface
 {
-    public function __construct(private SessionInterface $session)
+    private SessionInterface $session;
+
+    public function __construct(SessionInterface $session)
     {
+        $this->session = $session;
     }
 
     public function generate(): string
diff --git a/src/MaskedCsrfToken.php b/src/MaskedCsrfToken.php
index 6008b06..2498a8e 100644
--- a/src/MaskedCsrfToken.php
+++ b/src/MaskedCsrfToken.php
@@ -14,8 +14,11 @@
  */
 final class MaskedCsrfToken implements CsrfTokenInterface
 {
-    public function __construct(private CsrfTokenInterface $token)
+    private CsrfTokenInterface $token;
+
+    public function __construct(CsrfTokenInterface $token)
     {
+        $this->token = $token;
     }
 
     public function getValue(): string
diff --git a/src/Synchronizer/Generator/RandomCsrfTokenGenerator.php b/src/Synchronizer/Generator/RandomCsrfTokenGenerator.php
index 3cfe839..1faac8c 100644
--- a/src/Synchronizer/Generator/RandomCsrfTokenGenerator.php
+++ b/src/Synchronizer/Generator/RandomCsrfTokenGenerator.php
@@ -11,8 +11,11 @@
  */
 final class RandomCsrfTokenGenerator implements CsrfTokenGeneratorInterface
 {
-    public function __construct(private int $length = 32)
+    private int $length;
+
+    public function __construct(int $length = 32)
     {
+        $this->length = $length;
     }
 
     public function generate(): string
diff --git a/src/Synchronizer/Storage/SessionCsrfTokenStorage.php b/src/Synchronizer/Storage/SessionCsrfTokenStorage.php
index 22ee800..db47458 100644
--- a/src/Synchronizer/Storage/SessionCsrfTokenStorage.php
+++ b/src/Synchronizer/Storage/SessionCsrfTokenStorage.php
@@ -15,11 +15,20 @@ class SessionCsrfTokenStorage implements CsrfTokenStorageInterface
 {
     public const KEY = '_csrf';
 
+    /**
+     * @var string Session key used to store data.
+     */
+    private string $key;
+
+    private SessionInterface $session;
+
     /**
      * @param string $key Session key used to store data. Default is "_csrf".
      */
-    public function __construct(private SessionInterface $session, private string $key = self::KEY)
+    public function __construct(SessionInterface $session, string $key = self::KEY)
     {
+        $this->key = $key;
+        $this->session = $session;
     }
 
     public function get(): ?string
diff --git a/src/Synchronizer/SynchronizerCsrfToken.php b/src/Synchronizer/SynchronizerCsrfToken.php
index ca99d1d..36f8ff9 100644
--- a/src/Synchronizer/SynchronizerCsrfToken.php
+++ b/src/Synchronizer/SynchronizerCsrfToken.php
@@ -21,8 +21,15 @@
  */
 final class SynchronizerCsrfToken implements CsrfTokenInterface
 {
-    public function __construct(private CsrfTokenGeneratorInterface $generator, private CsrfTokenStorageInterface $storage)
-    {
+    private CsrfTokenGeneratorInterface $generator;
+    private CsrfTokenStorageInterface $storage;
+
+    public function __construct(
+        CsrfTokenGeneratorInterface $generator,
+        CsrfTokenStorageInterface $storage
+    ) {
+        $this->generator = $generator;
+        $this->storage = $storage;
     }
 
     public function getValue(): string
diff --git a/tests/Hmac/IdentityGenerator/MockCsrfTokenIdentityGenerator.php b/tests/Hmac/IdentityGenerator/MockCsrfTokenIdentityGenerator.php
index 0f4f7ed..11c3514 100644
--- a/tests/Hmac/IdentityGenerator/MockCsrfTokenIdentityGenerator.php
+++ b/tests/Hmac/IdentityGenerator/MockCsrfTokenIdentityGenerator.php
@@ -8,8 +8,11 @@
 
 final class MockCsrfTokenIdentityGenerator implements CsrfTokenIdentityGeneratorInterface
 {
-    public function __construct(private string $identity)
+    private string $identity;
+
+    public function __construct(string $identity)
     {
+        $this->identity = $identity;
     }
 
     public function generate(): string