diff --git a/a8/websocketsession.cc b/a8/websocketsession.cc
index 1cc582f..2ba5f8c 100644
--- a/a8/websocketsession.cc
+++ b/a8/websocketsession.cc
@@ -136,7 +136,7 @@ namespace a8
         std::string response = "HTTP/1.1 101 Web Socket Protocol Handshake\r\n"
             "Upgrade: websocket\r\n"
             "Connection: Upgrade\r\n"
-            + key + hash_data + "\r\n" +
+            + std::string(key) + hash_data + "\r\n" +
             "\r\n";
         SendBuff(response.data(), response.size());
         handshook_ = true;