In this paper we present a very practical ciphertext-only cryptanalysis of GSM (Global
System for Mobile communications) encrypted communication, and various active attacks on …

Establishing secure voice, video and text over Internet (VoIP) communications is a crucial
task necessary to prevent eavesdropping and man-in-the-middle attacks. The traditional …

We provide an extensive cryptographic analysis of Threema, a Swiss-based encrypted
messaging application with more than 10 million users and 7000 corporate customers. We …

We study the 5G-AKA authentication protocol described in the 5G mobile communication
standards. This version of AKA tries to achieve a better privacy than the 3G and 4G versions …

Social sign-on and social sharing are becoming an ever more popular feature of web
applications. This success is largely due to the APIs and support offered by prominent social …

The recent diversification of telephony infrastructure allows users to communicate through
landlines, mobile phones and VoIP phones. However, call metadata such as Caller-ID is …

We present a formal analysis of the authentication protocol of Facebook Connect, the Single
Sign-On service offered by the Facebook Platform which allows Facebook users to login to …

Conventional mobile social services such as Loopt and Google Latitude rely on two classes
of trusted relationships: participants trust a centralized server to manage their location …

In recent months a new generation of mobile messaging and VoIP applications for
smartphones was introduced. These services offer free calls and text messages to other …

In this paper, we propose a privacy-preserving contact tracing protocol for smart phones,
and more specifically Android and iOS phones. The protocol allows users to be notified, if …