diff --git a/snxconnect.py b/snxconnect.py
index 66e99b3..ceda453 100644
--- a/snxconnect.py
+++ b/snxconnect.py
@@ -380,7 +380,7 @@ def pad (self, txt) :
         if self.testing :
             r.append (b'\1' * n)
         else :
-            r.append (os.urandom (n))
+            r.append (bytes([x % 255 + 1 for x in os.urandom (n)]))
         r.append (b'\x02')
         r.append (b'\x00')
         return b''.join (reversed (r))