The first cryptography related talk at 28C3 is about data mining in encrypted data. One may assume, that encrypting your data with a good encryption scheme prevents other people from learning about it. However, this is not true, specially for network protocols, that often leak information, like who is communicating with who, and when how much data is transferred. An attacker can use these information to make assumptions about the content of the transmission.

From the abstract: Voice over IP (VoIP) has experienced a tremendous growth over the last few years and is now widely used among the …