Interference Alignment for the Multi-Antenna Compound Wiretap Channel

We study a wiretap channel model where the sender has $M$ transmit antennas and there are two groups consisting of $J_1$ and $J_2$ receivers respectively. Each receiver has a single antenna. We consider two scenarios. First we consider the compound wiretap model -- group 1 constitutes the set of legitimate receivers, all interested in a common message, whereas group 2 is the set of eavesdroppers. We establish new lower and upper bounds on the secure degrees of freedom. Our lower bound is based on the recently proposed \emph{real interference alignment} scheme. The upper bound provides the first known example which illustrates that the \emph{pairwise upper bound} used in earlier works is not tight. The second scenario we study is the compound private broadcast channel. Each group is interested in a message that must be protected from the other group. Upper and lower bounds on the degrees of freedom are developed by extending the results on the compound wiretap channel.Comment: Minor edits. Submitted to IEEE Trans. Inf. Theor

Multi-Service Group Key Establishment for Secure Wireless Mobile Multicast Networks

yesRecently there is high demand in distributing multimedia services over the internet to ubiquitous and computational intelligent mobile subscribers by the service providers (SPs). In this instance, provision of those services must be restricted to authorized subscribers via integration of authentication and group key management (GKM). GKM with diverse group services subscribed dynamically by moving subscribers in wireless networks has been omitted in conventional approaches. However it is expected that significant key management overhead will arise in them due to multi-services co-existing in the same network. In this paper, we propose a scalable decentralized multi-service GKM scheme considering host mobility in wireless environment. In the scheme, authentication of mobile subscribers and key management phases are delegated from the trusted domain key distributor (DKD) to the subgroup controllers known as area key distributors (AKD). The trusted intermediate AKDs can then establish and distribute the service group keys to valid subscribers in a distributed manner using identity-based encryption without involving the domain key distributor (DKD). This alleviates unnecessary delays and possible bottlenecks at the DKD. We show by simulation that the proposed scheme has some unique scalability properties over known schemes in terms of optimized rekeying communication and storage overheads. The security performance studies have shown resilience to various attacks

Lecture Notes on Network Information Theory

These lecture notes have been converted to a book titled Network Information Theory published recently by Cambridge University Press. This book provides a significantly expanded exposition of the material in the lecture notes as well as problems and bibliographic notes at the end of each chapter. The authors are currently preparing a set of slides based on the book that will be posted in the second half of 2012. More information about the book can be found at http://www.cambridge.org/9781107008731/. The previous (and obsolete) version of the lecture notes can be found at http://arxiv.org/abs/1001.3404v4/

Multilevel adaptive security system

Recent trends show increased demand for content-rich media such as images, videos and text in ad-hoc communication. Since such content often tends to be private, sensitive, or paid for, there exists a requirement for securing such information over resource constrained ad hoc networks. In this work, traditional data security mechanisms, existing ad hoc secure routing protocols and multilevel security are first reviewed. Then a new system, called the Multilevel Adaptive Security System, which incorporates the multilevel security concept at both the application layer and the network layer, is proposed to provide adaptive security services for data and routing processes. MLASS is composed of two subsystems: Content-Based Multi-level Data Security (CB-MLDS) for content-rich data protection and Multi-Level On-demand Secure Mobile Ad hoc Routing (MOSAR) for secure route selection. The structure of each sub-system is explained in detail; experiments for each sub-system were conducted and the performance was analyzed. It is shown that MLASS is a practical security solution that is flexible enough to adapt to a range of security requirements and applies appropriate level of security services to data and its distribution over ad hoc networks. MLASS provides a balance between security, performance and resource

Formal models and analysis of secure multicast in wired and wireless networks

The spreading of multicast technology enables the development of group communication and so dealing with digital streams becomes more and more common over the Internet. Given the flourishing of security threats, the distribution of streamed data must be equipped with sufficient security guarantees. To this aim, some architectures have been proposed, to supply the distribution of the stream with guarantees of, e.g., authenticity, integrity, and confidentiality of the digital contents. This paper shows a formal capability of capturing some features of secure multicast protocols. In particular, both the modeling and the analysis of some case studies are shown, starting from basic schemes for signing digital streams, passing through proto- cols dealing with packet loss and time-synchronization requirements, concluding with a secure distribution of a secret key. A process-algebraic framework will be exploited, equipped with schemata for analysing security properties and compositional principles for evaluating if a property is satisfied over a system with more than two components