diff --git a/ArchiSteamFarm/Bot.cs b/ArchiSteamFarm/Bot.cs
index 86077d7f3..ca4e408c1 100755
--- a/ArchiSteamFarm/Bot.cs
+++ b/ArchiSteamFarm/Bot.cs
@@ -98,7 +98,7 @@ namespace ArchiSteamFarm {
 
 		private static bool IsValidCdKey(string key) {
 			if (!string.IsNullOrEmpty(key)) {
-				return Regex.IsMatch(key, @"[0-9A-Z]{4,5}-[0-9A-Z]{4,5}-[0-9A-Z]{4,5}-?(?:(?:[0-9A-Z]{4,5}-?)?(?:[0-9A-Z]{4,5}))?");
+				return Regex.IsMatch(key, @"^[0-9A-Z]{4,5}-[0-9A-Z]{4,5}-[0-9A-Z]{4,5}(?:(?:-[0-9A-Z]{4,5})?(?:-[0-9A-Z]{4,5}))?$", RegexOptions.IgnoreCase);
 			}
 
 			Logging.LogNullError(nameof(key));