Talek: Private Group Messaging with Hidden Access Patterns

Talek is a private group messaging system that sends messages through potentially untrustworthy servers, while hiding both data content and the communication patterns among its users. Talek explores a new point in the design space of private messaging; it guarantees access sequence indistinguishability, which is among the strongest guarantees in the space, while assuming an anytrust threat model, which is only slightly weaker than the strongest threat model currently found in related work. Our results suggest that this is a pragmatic point in the design space, since it supports strong privacy and good performance: we demonstrate a 3-server Talek cluster that achieves throughput of 9,433 messages/second for 32,000 active users with 1.7-second end-to-end latency. To achieve its security goals without coordination between clients, Talek relies on information-theoretic private information retrieval. To achieve good performance and minimize server-side storage, Talek intro- duces new techniques and optimizations that may be of independent interest, e.g., a novel use of blocked cuckoo hashing and support for private notifications. The latter provide a private, efficient mechanism for users to learn, without polling, which logs have new messages

Mixes in mobile communication systems: Location management with privacy

This paper introduces a new technique for location management in cellular networks. It avoids the recording of moving tracks of mobile subscribers. The described procedures are derived from the well known untraceable MIX network and the distributed storage of location information according to GSM networks

Security in Public Mobile Communication Networks

Introduction The increasing use of mobile communication networks results in ever more stringent security requirements. In an information society, availability, integrity and confidentiality are essential. Especially the provision of the latter is hard to demonstrate. If someone or some component is able to collect and store personal data, one cannot be sure that this data is not gathered and not (mis)used. But this "being sure" is essential with respect to privacy and data protection. Therefore, legal means alone are insufficient and have to be complemented by technical means we are going to describe in the sequel. This first part is introductory and reflects the structure of future mobile communication networks. When users communicate in such networks there is much data generated which needs to be handled in a secure way. We present data protection and security requirements which we believe are the strongest ever presented. 1.1 Structure of Future Mobile Telecommun

Minimizing the Average Cost of Paging on the Air Interface -- An Approach Considering Privacy

Location Management of mobile users in a cellular network is considered from a performance and privacy point of view. Location management covers tracking functionality and paging (searching) functionality. After a risk analysis of location management w.r.t. privacy, we focus on the paging strategy. A sequential search strategy is proposed which reduces the signaling on the air interface and also considers the user's privacy