User-agent based access control for DLNA devices

DLNA based media sharing is very popular nowadays. In current DLNA specification, a DLNA device advertises its presence to everyone in the network. Any control point application receiving the advertisement can access/control the device. However, with increasing popularity and availability of public Wi-Fi hotspots, it is necessary for devices to have some sort of access control. DLNA specification has no mandatory authentication procedure. So a device receiving a request from any unwanted control point cannot block/verify its access. The UPnP recommended authentication procedure is computationally expensive and complex for most personal devices. So, in this paper we propose a simple User-Agent based access control system that is effective to protect devices from unwanted control point applications.