MAGETWO-98454: Investigation: Transaction MD5 hash field is removed by Authorize.net

Author: svitja

app/code/Magento/Authorizenet/Model/Directpost/Request.php

@@ -267,7 +267,7 @@ private function getSignatureKey()
      * @param string $signatureKey
      * @return void
      */
-    private function setSignatureKey(string $signatureKey)
+    private function setSignatureKey($signatureKey)
     {
         $this->signatureKey = $signatureKey;
     }

app/code/Magento/Authorizenet/Model/Directpost/Response.php

@@ -68,7 +68,7 @@ public function isApproved()
      * @return string
      * @see https://support.authorize.net/s/article/MD5-Hash-End-of-Life-Signature-Key-Replacement
      */
-    private function generateSha2Hash(string $signatureKey)
+    private function generateSha2Hash($signatureKey)
     {
         $hashFields = [
             'x_trans_id',

app/code/Magento/Authorizenet/Test/Unit/Model/Directpost/RequestTest.php

@@ -38,7 +38,7 @@ protected function setUp()
      * @return void
      * @dataProvider signRequestDataProvider
      */
-    public function testSignRequestData(string $signatureKey, string $expectedHash)
+    public function testSignRequestData($signatureKey, $expectedHash)
     {
         /** @var \Magento\Authorizenet\Model\Directpost|\PHPUnit_Framework_MockObject_MockObject $paymentMethod */
         $paymentMethod = $this->getMock(\Magento\Authorizenet\Model\Directpost::class, [], [], '', false);

app/code/Magento/Authorizenet/Test/Unit/Model/Directpost/ResponseTest.php

@@ -48,13 +48,13 @@ protected function generateHash($merchantMd5, $merchantApiLogin, $amount, $trans
      * @dataProvider isValidHashDataProvider
      */
     public function testIsValidHash(
-        string $storedHash,
-        string $hashKey,
-        string $merchantApiLogin,
+        $storedHash,
+        $hashKey,
+        $merchantApiLogin,
         $amount,
-        string $transactionId,
-        string $hash,
-        bool $expectedValue
+        $transactionId,
+        $hash,
+        $expectedValue
     ) {
         $this->responseModelMock->setXAmount($amount);
         $this->responseModelMock->setXTransId($transactionId);