diff --git a/server.go b/server.go
index dc83934..b0cb150 100644
--- a/server.go
+++ b/server.go
@@ -224,7 +224,7 @@ func timestampOldThan(ts int32, sec int32) bool {
 
 func buildSignature(token string) (signature, timestamp, nonce string) {
 	timestamp = fmt.Sprintf("%d", int32(time.Now().Unix()))
-	nonce = "1461107899" //a randome string cut from previous wechat request
+	nonce = RandStringRunes(10) // "1461107899" //a randome string cut from previous wechat request
 	signature = calculateSignature(timestamp, nonce, token)
 	return
 }