A Survey on Mix Networks and Their Secure Applications

Anonymity is a subdiscipline of information hiding, required in a number of applications, such as in electronic voting. For network communications, anonymity can be provided by a mix network (mixnet). A mixnet is a multistage system that uses cryptography and permutations to provide anonymity. The basic idea of a mixnet has evolved into a number of different classes. In addition to presenting the existing mixnet classifications, this paper classifies mixnets based on the verification mechanisms employed for robustness. The construction of mixnets is presented under a common framework to provide insight into both the design and weaknesses of existing solutions. Basic forms of attack on mixnets and the corresponding robustness solutions are reviewed. Comparison with other solutions for anonymity and suggestions for interesting future research in mix networks are also provided     

AMOEBA: Robust Location Privacy Scheme for VANET

Communication messages in vehicular ad hoc networks (VANET) can be used to locate and track vehicles. While tracking can be beneficial for vehicle navigation, it can also lead to threats on location privacy of vehicle user. In this paper, we address the problem of mitigating unauthorized tracking of vehicles based on their broadcast communications, to enhance the user location privacy in VANET. Compared to other mobile networks, VANET exhibits unique characteristics in terms of vehicular mobility constraints, application requirements such as a safety message broadcast period, and vehicular network connectivity. Based on the observed characteristics, we propose a scheme called AMOEBA, that provides location privacy by utilizing the group navigation of vehicles. By simulating vehicular mobility in freeways and streets, the performance of the proposed scheme is evaluated under VANET application constraints and two passive adversary models. We make use of vehicular groups for anonymous access to location based service applications in VANET, for user privacy protection. The robustness of the user privacy provided is considered under various attacks.