diff --git a/src/Message/SIMCompleteAuthorizeRequest.php b/src/Message/SIMCompleteAuthorizeRequest.php
index f10ffb9b..a36ea1f2 100644
--- a/src/Message/SIMCompleteAuthorizeRequest.php
+++ b/src/Message/SIMCompleteAuthorizeRequest.php
@@ -21,7 +21,7 @@ public function getTransactionId()
     public function getData()
     {
         // The hash sent in the callback from the Authorize.Net gateway.
-        $hash_posted = $this->getPostedHash($this->httpRequest);
+        $hash_posted = $this->getPostedHash();
 
         // The transaction reference generated by the Authorize.Net gateway and sent in the callback.
         $posted_transaction_reference = $this->httpRequest->request->get('x_trans_id');
@@ -30,7 +30,7 @@ public function getData()
         $posted_amount = $this->httpRequest->request->get('x_amount');
 
         // Calculate the hash locally, using the shared "hash secret" and login ID.
-        $hash_calculated = $this->getHash($posted_transaction_reference, $posted_amount, $this->httpRequest);
+        $hash_calculated = $this->getHash($posted_transaction_reference, $posted_amount);
 
         if ($hash_posted !== $hash_calculated) {
             // If the hash is incorrect, then we can't trust the source nor anything sent.
@@ -68,10 +68,10 @@ public function getData()
      * @param $httpRequest
      * @return string
      */
-    public function getHash($transaction_reference, $amount, $httpRequest)
+    public function getHash($transaction_reference, $amount)
     {
-        if (!empty($httpRequest) && $hash = $this->getSha512Hash($httpRequest)) {
-            return $hash;
+        if ($this->getSignatureKey()) {
+            return $this->getSha512Hash();
         } else {
             return $this->getMd5Hash($transaction_reference, $amount);
         }
@@ -98,48 +98,51 @@ public function getMd5Hash($transaction_reference, $amount)
 
     /**
      * Generate sha512 hash.
-     * Required fields are provided in Table 18 in https://www.authorize.net/content/dam/authorize/documents/SIM_guide.pdf#page=73
+     * Required fields are provided in Table 18 in
+     * https://www.authorize.net/content/dam/authorize/documents/SIM_guide.pdf#page=73
      * @param $httpRequest
      * @return string|null
      */
-    public function getSha512Hash($httpRequest)
+    public function getSha512Hash()
     {
         $signatureKey = $this->getSignatureKey();
-        if (empty($signatureKey) || empty($httpRequest)) {
+        $httpRequest = $this->httpRequest->request;
+
+        if (empty($signatureKey)) {
             return null;
         }
 
         $hashData = implode('^', [
-            $httpRequest->request->get('x_trans_id'),
-            $httpRequest->request->get('x_test_request'),
-            $httpRequest->request->get('x_response_code'),
-            $httpRequest->request->get('x_auth_code'),
-            $httpRequest->request->get('x_cvv2_resp_code'),
-            $httpRequest->request->get('x_cavv_response'),
-            $httpRequest->request->get('x_avs_code'),
-            $httpRequest->request->get('x_method'),
-            $httpRequest->request->get('x_account_number'),
-            $httpRequest->request->get('x_amount'),
-            $httpRequest->request->get('x_company'),
-            $httpRequest->request->get('x_first_name'),
-            $httpRequest->request->get('x_last_name'),
-            $httpRequest->request->get('x_address'),
-            $httpRequest->request->get('x_city'),
-            $httpRequest->request->get('x_state'),
-            $httpRequest->request->get('x_zip'),
-            $httpRequest->request->get('x_country'),
-            $httpRequest->request->get('x_phone'),
-            $httpRequest->request->get('x_fax'),
-            $httpRequest->request->get('x_email'),
-            $httpRequest->request->get('x_ship_to_company'),
-            $httpRequest->request->get('x_ship_to_first_name'),
-            $httpRequest->request->get('x_ship_to_last_name'),
-            $httpRequest->request->get('x_ship_to_address'),
-            $httpRequest->request->get('x_ship_to_city'),
-            $httpRequest->request->get('x_ship_to_state'),
-            $httpRequest->request->get('x_ship_to_zip'),
-            $httpRequest->request->get('x_ship_to_country'),
-            $httpRequest->request->get('x_invoice_num'),
+            $httpRequest->get('x_trans_id'),
+            $httpRequest->get('x_test_request'),
+            $httpRequest->get('x_response_code'),
+            $httpRequest->get('x_auth_code'),
+            $httpRequest->get('x_cvv2_resp_code'),
+            $httpRequest->get('x_cavv_response'),
+            $httpRequest->get('x_avs_code'),
+            $httpRequest->get('x_method'),
+            $httpRequest->get('x_account_number'),
+            $httpRequest->get('x_amount'),
+            $httpRequest->get('x_company'),
+            $httpRequest->get('x_first_name'),
+            $httpRequest->get('x_last_name'),
+            $httpRequest->get('x_address'),
+            $httpRequest->get('x_city'),
+            $httpRequest->get('x_state'),
+            $httpRequest->get('x_zip'),
+            $httpRequest->get('x_country'),
+            $httpRequest->get('x_phone'),
+            $httpRequest->get('x_fax'),
+            $httpRequest->get('x_email'),
+            $httpRequest->get('x_ship_to_company'),
+            $httpRequest->get('x_ship_to_first_name'),
+            $httpRequest->get('x_ship_to_last_name'),
+            $httpRequest->get('x_ship_to_address'),
+            $httpRequest->get('x_ship_to_city'),
+            $httpRequest->get('x_ship_to_state'),
+            $httpRequest->get('x_ship_to_zip'),
+            $httpRequest->get('x_ship_to_country'),
+            $httpRequest->get('x_invoice_num'),
         ]);
         $hash = hash_hmac('sha512', '^' . $hashData . '^', hex2bin($signatureKey));
         $hash = strtoupper($hash);
@@ -150,20 +153,15 @@ public function getSha512Hash($httpRequest)
     /**
      * Get posted hash from the callback from the Authorize.Net gateway.
      *
-     * @param $httpRequest
      * @return string|null
      */
-    public function getPostedHash($httpRequest)
+    public function getPostedHash()
     {
-        if (empty($httpRequest)){
-            return null;
-        }
-
         if ($signatureKey = $this->getSignatureKey()) {
-            return strtoupper($httpRequest->request->get('x_SHA2_Hash'));
+            return strtoupper($this->httpRequest->request->get('x_SHA2_Hash'));
         }
 
-        return strtolower($httpRequest->request->get('x_MD5_Hash'));
+        return strtolower($this->httpRequest->request->get('x_MD5_Hash'));
     }
 
     public function sendData($data)