Index: uc_credit.module
===================================================================
--- uc_credit.module	(revision 4830)
+++ uc_credit.module	(working copy)
@@ -514,7 +514,11 @@ function uc_payment_method_credit($op, &
       $crypt = new uc_encryption_class;
 
       // Store the encrypted details in the session for the next pageload.
-      $_SESSION['sescrd'] = $crypt->encrypt($key, serialize($arg1->payment_details));
+      // We are using base64_encode because the encrypt function works with a limited set of
+      // characters, not supporting unicode and other extended ASCII characters that are
+      // present on international names. base64 converts everything to the standard
+      // ascii alphabet. 
+      $_SESSION['sescrd'] = $crypt->encrypt($key, base64_encode(serialize($arg1->payment_details)));
 
       // Log any errors to the watchdog.
       uc_store_encryption_errors($crypt, 'uc_credit');
@@ -1212,6 +1216,15 @@ function uc_credit_cache($op, $data = NU
 
       // Save the unencrypted CC details for the duration of this request.
       $cc_cache = unserialize($crypt->decrypt($key, $data));
+      if ($cc_cache === FALSE) {
+        // In recent versions, we are base64_encoding the payment
+        // details before encrypting, but to be backward compatible between upgrades,
+        // and because after such an upgrade some of the data might have been stored
+        // w/o that encoding we first try to unserialize the encrypted data itself,
+        // if that fails, we assume it's the new format and we decode it before 
+        // unserializing it.
+        $cc_cache = unserialize(base64_decode($crypt->decrypt($key, $data)));
+      }
     }
     else {
       $cc_cache = $data;