diff --git a/README.md b/README.md
index 53efd9f9..f066c3af 100644
--- a/README.md
+++ b/README.md
@@ -27,10 +27,9 @@ It is highly recommended to install the latest release from Github (either using
 - Supports the multi-shipping extension
 - Supports simplified PCI DSS conformity in accordance with SAQ A
 - Payment methods can be automatically hidden depending on the amount of the order and the credit rating of the customer
-- Find all currently supported payment methods on [the dedicated docs' page on our site](https://docs.payone.com/display/public/INT/Magento+1+Extension)
 
 ## Documentation
-You can check [the documentation on our website here](https://docs.payone.com/display/public/INT/Magento+1+Extension).
+You can our documentation here: https://docs.payone.com/integration/plugins/integration-guide-magento-1.
 
 ## Notes
 
diff --git a/lib/Payone/ClientApi/Service/GenerateHash.php b/lib/Payone/ClientApi/Service/GenerateHash.php
index 1ad60ae6..aa85c86e 100644
--- a/lib/Payone/ClientApi/Service/GenerateHash.php
+++ b/lib/Payone/ClientApi/Service/GenerateHash.php
@@ -103,8 +103,7 @@ public function generate(Payone_ClientApi_Request_Interface $request, $securityK
             $hashString .= $requestData[$key];
         }
 
-        $hashString .= $securityKey;
-        $hash = md5($hashString);
+        $hash = hash_hmac('sha384', $hashString, $securityKey);
         return $hash;
     }