In this paper, we study the two-user one-sided interference channel with confidential messages. In this interference channel, in addition to the usual selfishness of the users, the relationship between the two pairs of users is further adversarial in the sense of both receivers' desires to eavesdrop on the communication of the other pair. We develop a game-theoretic model to study the information-theoretic secure communications in this setting. We first start with a game-theoretic model where each pair's payoff is their own secrecy rate. The analysis of the binary deterministic interference channel with this payoff function shows that self-jamming of a transmitter, which injures the eavesdropping ability of its own receiver, is not excluded by the Nash equilibria. We propose a refinement for the payoff function by explicitly accounting for the desire of the receiver to eavesdrop on the other party's communication. This payoff function captures the adversarial relationship between the two pairs of users better. We determine the Nash equilibria for the binary deterministic channel for both payoff functions.
In this paper, we study the two-user one-sided interference channel with confidential messages. In this interference channel, in addition to the usual selfishness of the users, the relationship between the two pairs of users is further adversarial in the sense of both receivers' desires to eavesdrop on the communication of the other pair. We develop a game-theoretic model to study the information-theoretic secure communications in this setting. We first start with a game-theoretic model where each pair's payoff is their own secrecy rate. The analysis of the binary deterministic interference channel with this payoff function shows that self-jamming of a transmitter, which injures the eavesdropping ability of its own receiver, is not excluded by the Nash equilibria. We propose a refinement for the payoff function by explicitly accounting for the desire of the receiver to eavesdrop on the other party's communication. This payoff function captures the adversarial relationship between the two pairs of users better. We determine the Nash equilibria for the binary deterministic channel for both payoff functions.
We investigate the secure degrees of freedom (s.d.o.f.) of two new channel models: broadcast channel with combating helpers and interference channel with selfish users. In the first model, over a classical broadcast channel with confidential messages (BCCM), there are two helpers, each associated with one of the receivers. In the second model, over a classical interference channel with confidential messages (ICCM), there is a helper and users are selfish. The goal of introducing these channel models is to investigate various malicious interactions that arise in networks, including active adversaries. By casting each problem as an extensive-form game and applying recursive real interference alignment, we show that, for the first model, the combating intentions of the helpers are neutralized and the full s.d.o.f. is retained; for the second model, selfishness precludes secure communication and no s.d.o.f. is achieved.
A secure communication game is considered for the two-user MISO Gaussian interference channel with confidential messages, where each transmitter aims to maximize the difference between its secrecy rate and the secrecy rate of the other transmitter. In this novel problem, the weaker link tries to minimize the extra secret information obtained by its adversary, while the stronger link attempts to maximize it. We provide an information theoretic formulation for this non-cooperative zero-sum game scenario and determine that, under the assumption of Gaussian signaling at the transmitters, there exists a unique Nash equilibrium solution for the proposed problem. Moreover, we obtain in closed-form the optimal strategies (beamformers) at the transmitters that result in the Nash equilibrium. While the NE strategies are achievable in one shot when full channel state information is available at the transmitters (CSIT), we also propose an iterative step-by-step algorithm that converges to the NE point, but only requires limited CSIT. Numerical results are presented to illustrate the analytical findings and to study the role of different channel parameters on the NE strategies.
This letter proposes a game-theoretic model to jointly optimize artificial noise and information signals in a two-user weak Gaussian interference channel. In this channel, each receiver not only is interested in its related transmitter's message, but also it is an eavesdropper for the other link. Transmitters may broadcast noise in addition to data in order to confuse eavesdroppers. In this context, the secrecy rate is referred to as the utility, and the Nash equilibrium outcome in the related non-cooperative power splitting game is inefficient. By introducing a novel price-based potential game, we obtain Pareto improvement in the secrecy sum-rate. Numerical results confirm our analytical development.
We consider adding secrecy constraints to a model of information theoretic games introduced in earlier works. In these games, each user autonomously selects their encoding and decoding strategy with the objective of maximizing their own secure rate in the presence of a single eavesdropper. We study the Nash equilibrium regions for such games when the users are communicating over linear deterministic models of a multiple access channel and an interference channel. In particular, we show that for interference channels, the presence of an eavesdropper results in significantly different equilibrium properties when an eavesdropper is not present.
The growth of wireless networks has been considerable over the last decades. Due to the broadcast nature of these networks, security issues have taken a critical role in today’s communications. A promising direction towards achieving secure communications is information theoretic secrecy, which is an approach exploiting the randomness of the channels to ensure secrecy. Based on this approach, there has been a recent surge of interest in a potential cooperation between users to enhance the secrecy of communications. In this thesis we investigate the interaction between cooperation and secrecy. In particular the contributions of the thesis can be divided into two parts. In the first part, we study cooperative strategies for secrecy for wireless channels. Our goal is to evaluate the effect of fading and limited CSI on the eavesdropper’s channels. In that purpose we consider a scenario where a helper aims at increasing the secrecy of the communication between a source and destination in the presence of an eavesdropper. Several strategies are discussed for the helper, namely decode-and-forward, amplify-and-forward, and cooperative jamming. We introduce the secrecy outage probability, the conditional secrecy outage probability and the secure throughput as secrecy measures. For each measure, we investigate and compare the secrecy performance of cooperation. We furthermore elaborate a system optimization in terms of strategy selection, node positioning, power allocation and rate design. In the second part, we consider cooperation in the 4-node scenario against a more sophisticated adversary: an active eavesdropper, which can either passively eavesdrop, or jam the transmission. A game-theoretic perspective is a natural way to analyze the competitive interaction between the helper and the eavesdropper. Therefore we define several secrecy games, for which we find the Nash and Stackelberg equilibria as well as the corresponding secrecy rate outcomes. Another important consideration in this scenario is the interaction between the source and the helper, which we model and solve as a Stackelberg game, and we illustrate its impact on the achievable secrecy rates.
We consider an interference network tapped by external eavesdropper(s) in which each legitimate transmit-receive pair conceals its communications by using joint transmit-based friendly jamming (TxFJ) and receiver-based friendly jamming (RxFJ). Specifically, TxFJ is realized at the transmit side using MIMO precoding while RxFJ is achieved at the receiver side of each link by leveraging the state-of-the-art self-interference-suppression techniques (allowing a radio to cancel the self-interference effect of its transmit signal). We show that with a careful power allocation between the information signal and TxFJ at the transmit side of each link, the corresponding receiver is able decide on using RxFJ independent of any multi-user interference factor. This ability sets the receivers free from having to measure multi-user interference at eavesdropper(s). With every link following such strategy, we model this interaction as a non-cooperative game. We derive sufficient conditions under which the game admits a unique Nash equilibrium. We then propose a robust version of the game that requires only statistical knowledge of eavesdropping channel.