Anonymous Communication in the Digital World

Privacy on the Internet is becoming a concern as an already significant and ever growing part of our daily activities is carried out online. While cryptography can be used to protect the integrity and confidentiality of contents of communication, everyone along the route on which a packet is traveling can still observe the addresses of the respective communication parties. This often is enough to uniquely identify persons participating in a communication. Anonymous communication is used to hide relationships between the communicating parties. These relationships as well as patterns of communication can often be as revealing as their content. Hence, anonymity is a key technology needed to retain privacy in communications. This paper provides a very brief overview of my doctoral dissertation "Anonymous Communication in the Age of the Internet" [A. Panchenko. Anonymous Communication in the Age of the Internet. PhD thesis, Department of Computer Science, RWTH Aachen University, 2010] and then concisely focuses on one randomly selected aspect, namely, the attack on the anonymization concept called Crowds.