Converting the sign key from hex to byte format.

PaymentDatatrans.php

@@ -63,8 +63,8 @@ public function processPostSale()
 		}
 
 		// Validate HMAC sign
-		if ($this->Input->post('sign2') != hash_hmac('md5', $this->datatrans_id.$this->Input->post('amount').$this->Input->post('currency').$this->Input->post('uppTransactionId'), $this->datatrans_sign))
-		{
+        if ($this->Input->post('sign2') != hash_hmac('md5', $this->datatrans_id.$this->Input->post('amount').$this->Input->post('currency').$this->Input->post('uppTransactionId'), $this->convertHexStringToByteString($this->datatrans_sign)))
+        {
 			$this->log('Invalid HMAC signature for Order ID ' . $this->Input->post('refno'), __METHOD__, TL_ERROR);
 			return false;
 		}
@@ -173,7 +173,7 @@ public function checkoutForm()
 		);
 
 		// Security signature (see Security Level 2)
-		$arrParams['sign'] = hash_hmac('md5', $arrParams['merchantId'].$arrParams['amount'].$arrParams['currency'].$arrParams['refno'], $this->datatrans_sign);
+		$arrParams['sign'] = hash_hmac('md5', $arrParams['merchantId'].$arrParams['amount'].$arrParams['currency'].$arrParams['refno'], $this->convertHexStringToByteString($this->datatrans_sign));
 
 		$objTemplate = new FrontendTemplate('iso_payment_datatrans');
 		$objTemplate->id = $this->id;
@@ -185,7 +185,17 @@ public function checkoutForm()
 
 		return $objTemplate->parse();
 	}
-
+
+	/**
+	 * Converts the sign key from the hex format you get from the Datatrans interface to the byte format that is needed to actually hash transaction requests
+	 * @param $hexString String The sign key from the datatrans interface
+	 * @return string The byte-formatted sign key needed as the key to hash the request parameters
+	 */
+	private function convertHexStringToByteString($hexString) {
+		$result = "";
+		for($i=0;$i<strlen($hexString);$i += 2) $result .= chr(hexdec($hexString[$i].$hexString[$i+1]));
+		return $result;
+	}
 
 	/**
 	 * Validate array of post parameter agains required values

README.txt

@@ -13,3 +13,7 @@ After this please log in your datatrans admin panel and insert the correct url's
 
 For more security please activate the sign parameter security. Only with this your payment
 process is 100% secured. You can generate the sign parameter in the datatrans admin panel.
+
+Note:
+	If you use the sign parameter, it is automatically converted to byte format for you.
+	Just copy it from the DataTrans control panel and isotope-datatrans converts it for you.

languages/de/tl_iso_payment_modules.php

@@ -33,5 +33,5 @@
  * Fields
  */
 $GLOBALS['TL_LANG']['tl_iso_payment_modules']['datatrans_id']	= array('Merchant-ID', 'Bitte geben Sie ihre Datatrans Merchant-ID ein.');
-$GLOBALS['TL_LANG']['tl_iso_payment_modules']['datatrans_sign']	= array('HMAC-Schlüssel', 'Bitte geben Sie den HMAC-Schlüssel aus Ihrem Datatrans Control Panel ein.');
+$GLOBALS['TL_LANG']['tl_iso_payment_modules']['datatrans_sign']	= array('HMAC-Schlüssel', 'Bitte geben Sie den HMAC-Schlüssel aus Ihrem Datatrans Control Panel ein (wie dort angezeigt, er wird automatisch konvertiert).');
 

languages/en/tl_iso_payment_modules.php

@@ -33,5 +33,5 @@
  * Fields
  */
 $GLOBALS['TL_LANG']['tl_iso_payment_modules']['datatrans_id']	= array('Merchant-ID', 'Please enter your merchant ID.');
-$GLOBALS['TL_LANG']['tl_iso_payment_modules']['datatrans_sign']	= array('HMAC Key', 'Please enter your HMAC key from the Datatrans control panel.');
+$GLOBALS['TL_LANG']['tl_iso_payment_modules']['datatrans_sign']	= array('HMAC Key', 'Please enter your HMAC key from the Datatrans control panel (as seen there in hex format, it is automatically converted).');