In this work we study the secrecy capacity of Gaussian multiple-input multiple-output (MIMO) wiretap channels (WTCs) with a finite memory, subject to a per-symbol average power constraint on the MIMO channel input. MIMO channels with finite memory are very common in wireless communications as well as in wireline communications (e.g., in communications over power lines). To derive the secrecy ca...

Abstract We study the optimum location of an eavesdropper from a secrecy capacity perspective in multi-terminal networks with power control. We determine the logical location of an eavesdropper (represented by the channel gain from all the transmitters) which a) results in zero secrecy capacity for maximum number of users in the network and b) results in zero secrecy capacity for the bottle-nec...

The secrecy capacity of a discrete memoryless Gaussian Wire-Tap Channel when the input is from a finite complex constellation is studied. It is shown that the secrecy capacity curves of a finite constellation plotted against the SNR, for a fixed noise variance of the eavesdropper’s channel has a global maximum at an internal point. This is in contrast to what is known in the case of Gaussian co...

In this work the arbitrarily varying wiretap channel AVWC is studied. We derive a lower bound on the random code secrecy capacity for the average error criterion and the strong secrecy criterion in the case of a best channel to the eavesdropper by using Ahlswede’s robustification technique for ordinary AVCs. We show that in the case of a non-symmetrisable channel to the legitimate receiver the ...

We consider power control in multi-terminal networks and study its impact on secrecy capacities of transmitreceive pairs. Note that most approaches in the current literature on secrecy capacity consider only single terminals. Impact of power control on secrecy capacity has seldom been studied. This paper investigates a new approach using the theory of M−matrices to utility based power control w...

In this paper, we investigate the effect of output quantization on the secrecy capacity of the binary-input Gaussian wiretap channel. As a result, a closed-form expression with infinite summation terms of the secrecy capacity of the binary-input Gaussian wiretap channel is derived for the case when both the legitimate receiver and the eavesdropper have unquantized outputs. In particular, comput...

Incorporating the physical layer characteristics to secure communications has received considerable attention in recent years. Moreover, cooperation with some nodes of network can give benefits of multiple-antenna systems, increasing the secrecy capacity of such channels. In this paper, we consider cooperative wiretap channel with the help of an Amplify and Forward (AF) relay to transmit confid...

Different security measurements for a steganographic system, i.e. security (detectability), robustness and secrecy (difficulty of extraction), are discussed in this paper. We propose a new measurement for the security of stegosystems using variational distance which can upper bound the advantage for passive attackers. It is proved that the hiding capacity, which is also the measurement for robu...

With the advent of quantum key distribution (QKD) systems, perfect (i.e. information-theoretic) security can now be achieved for distribution of a cryptographic key. QKD systems and similar protocols use classical errorcorrecting codes for both error correction (for the honest parties to correct errors) and privacy amplification (to make an eavesdropper fully ignorant). From a coding perspectiv...

This paper introduces the reader to several information theoretic aspects of covert communications. In particular, it discusses fundamental limits on the amount of information that can be reliably communicated in such a way that a malevolent third-party observer cannot decode the messages. This situation is considered first for a system with a single intended receiver, and then extensions of se...