diff --git a/websocket-sharp/Net/WebSockets/TcpListenerWebSocketContext.cs b/websocket-sharp/Net/WebSockets/TcpListenerWebSocketContext.cs
index 04f9c442..473cdb17 100644
--- a/websocket-sharp/Net/WebSockets/TcpListenerWebSocketContext.cs
+++ b/websocket-sharp/Net/WebSockets/TcpListenerWebSocketContext.cs
@@ -497,15 +497,6 @@ namespace WebSocketSharp.Net.WebSockets
       _tcpClient.Close ();
     }
 
-    internal void SendAuthenticationChallenge (string challenge)
-    {
-      var res = HttpResponse.CreateUnauthorizedResponse (challenge);
-      var bytes = res.ToByteArray ();
-      _stream.Write (bytes, 0, bytes.Length);
-
-      _request = HttpRequest.Read (_stream, 15000);
-    }
-
     #endregion
 
     #region Public Methods