diff --git a/SermepaConnection.php b/SermepaConnection.php
index 2af0889..a528c7c 100644
--- a/SermepaConnection.php
+++ b/SermepaConnection.php
@@ -56,9 +56,12 @@
   }
 
   private function encryptOrderCode( $key, $orderCode ){
-    $iv = implode(array_map("chr", array(0,0,0,0,0,0,0,0)));
-    $ciphertext = mcrypt_encrypt(MCRYPT_3DES, $key, $orderCode, MCRYPT_MODE_CBC, $iv);
-    return $ciphertext;
+    $iv = "\0\0\0\0\0\0\0\0";
+    $data_padded = $orderCode;
+    if (strlen($data_padded) % 8) {
+        $data_padded = str_pad($data_padded, strlen($data_padded) + 8 - strlen($data_padded) % 8, "\0");
+    }
+    return openssl_encrypt($data_padded, "DES-EDE3-CBC", $key, OPENSSL_RAW_DATA | OPENSSL_NO_PADDING, $iv);
   }
 
 }