A privacy protection system for HbbTV in Smart TVs

The popularity of smart entertainment devices is growing every day. Products like blu-ray players, set-top boxes and Smart TVs (STV) with high connectivity are on the market. Many of them connect to the Internet via LAN or WiFi. Especially Smart TVs enable the broadcasting stations to provide real-time information directly to the consumers, for example additional information about a current TV program. HbbTV is one of the standards on STV for combining the two data media DVB and Internet. It defines how commonly used web technologies can be used as a transparent overlay over the current channel. Each respective broadcasting station is responsible for the contents of their channels' HbbTV signals. In this article, we describe how broadcasting stations measure the consumers viewing behavior more accurately using HbbTV. We show which technologies are used and which cause privacy risks, i.e., which methods lead to the exposure of personal preferences. Additionally, we describe a method how an evil-minded neighbor is able to monitor the viewing behavior without the user's knowledge and consent. This method is possible on most channels using HbbTV. It is not even required that the user actively starts the HbbTV application. Beyond that, we can collect this data on an encrypted WiFi network as well. Finally, we discuss our implementation for significantly reducing the privacy risk HbbTV poses.