diff --git a/main_form.cs b/main_form.cs
index 46c9332..5f712eb 100644
--- a/main_form.cs
+++ b/main_form.cs
@@ -104,10 +104,10 @@ namespace KRY_0x01_ng
                 return false;
             }
 
-            Match match = Regex.Match(str_to_check, @"\d|\s+");
+            Match match = Regex.Match(str_to_check, @"\d|\s+|W");
             if (match.Success)
             {
-                MessageBox.Show("Only alphabetic characters are allowed.\nCheck the key for numbers, symbols or tab whitespace and remove them before continuing.", "Error: invalid chars in key");
+                MessageBox.Show("Only alphabetic characters (with the exception of 'W') are allowed.\nCheck the key for numbers, symbols or tab whitespace and remove them before continuing.", "Error: invalid chars in key");
                 return false;
             }