diff --git a/plugin/multiplex/index.js b/plugin/multiplex/index.js
index 0b03fc7c6b62b6f1a78cb19195c22f3932f7f6af..35df8e3919b6361152798f46b36ef3fa2c58aca8 100644
--- a/plugin/multiplex/index.js
+++ b/plugin/multiplex/index.js
@@ -15,6 +15,7 @@ var opts = {
 
 io.sockets.on('connection', function(socket) {
 	socket.on('slidechanged', function(slideData) {
+		if (typeof slideData.secret == 'undefined' || slideData.secret == null || slideData.secret === '') return;
 		if (createHash(slideData.secret) === slideData.socketId) {
 			slideData.secret = null;
 			socket.broadcast.emit(slideData.socketId, slideData);