Open Source Based Privacy-Proxy to Restrain Connectivity of Mobile Apps

Mobile Devices are part of our lives and we store a lot of private information on it as well as use services that handle sensitive information (e.g. mobile health apps). Whenever users install an application on their smartphones they have to decide whether to trust the applications and share private and sensitive data with at least the developer-owned services. But almost all modern apps not only transmit data to the developer owned servers but also send information to advertising-, analyzing and tracking partners. This paper presents an approach for a "privacy- proxy" which enables to filter unwanted data traffic to third party services without installing additional applications on the smartphone. It is based on a firewall using a black list of tracking- and analyzing networks which is automatically updated on a daily basis. The proof of concept has been implemented with open source components on a Raspberry Pi.