This work considers the two way wiretap channel in which two legitimate users, Alice and Bob, wish to exchange messages securely in the presence of a passive eavesdropper Eve. In the full duplex scenario, where each node can transmit and receive simultaneously, we obtain new achievable secrecy rate regions based on the idea of allowing the two users to jointly optimize their channel prefixing d...

Equivocation rate has been widely used as an information-theoretic measure of security after Shannon[12]. It simplifies problems by removing the effect of atypical behavior from the system. In [11], however, Merhav and Arikan considered the alternative of using guessing exponent to analyze the Shannon’s cipher system. Because guessing exponent captures the atypical behavior, the strongest expre...

T his thesis studies physical layer security for multi-user multiple-input multiple-output (MIMO) wireless systems. Due to the broadcast nature of the physical medium, wireless multi-user communications are very susceptible to eavesdropping, and it is critical to protect the transmitted information. Security of wireless communications has traditionally been achieved at the network layer with cr...

One of the basic problems in cryptography is the generation of a common secret key between two parties, for instance in order to communicate privately. In this paper we consider information-theoretically secure key agreement. Wyner and subsequently Csiszár and Körner described and analyzed settings for secret-key agreement based on noisy communication channels. Maurer as well as Ahlswede and Cs...

In this paper, we formulate the resource allocation problem for secure communications in a single cell OFDMA network where a base station wants to communicate to the users which are spread over its coverage area while an adversary is present in the network. In our model, we assume that the adversary s an active attacker which is able to either eavesdrop on the information transmitted over the w...

We investigate the optimality and power allocation algorithm of beam domain transmission for single-cell massive multiple-input multiple-output (MIMO) systems with a multiantenna passive eavesdropper. Focusing on the secure massive MIMO downlink transmission with only statistical channel state information of legitimate users and the eavesdropper at base station, we introduce a lower bound on th...

In a premier paper on the information-theoretic analysis of a two-user cognitive interference channel (CIC) [1], Devroye et al. presented an achievable rate region for the two-user discrete memoryless CIC. The coding scheme proposed by Devroye et al. is correct but unfortunately some rate-terms in the derived achievable rate region are incorrect (in fact incomplete) because of occurring some mi...