We consider a communication system where a relay helps transmission of messages from a sender to a receiver. The relay is considered not only as a helper but as a wire-tapper who can obtain some knowledge about transmitted messages. In this paper we study a relay channel with confidential messages(RCC), where a sender attempts to transmit common information to both a receiver and a relay and al...

We introduce a new measure on secrecy, which is established based on rate-distortion theory. It is named security rate, which is the minimum (infimum) of the additional rate needed to reconstruct the source within target distortion level with any positive probability for wiretapper. It denotes the minimum distance in information metric (bits) from what wiretapper has received to any decrypted r...

A discrete memoryless generalized multiple access channel (GMAC) with confidential messages is studied, where two users attempt to transmit common information to a destination and each user also has private (confidential) information intended for the destination. This channel generalizes the multiple access channel (MAC) in that the two users also receive channel outputs, and hence may obtain t...

Abstract— A discrete memoryless generalized multiple access channel (GMAC) with confidential messages is studied, where two users attempt to transmit common information to a destination and each user also has private (confidential) information intended for the destination. This channel generalizes the multiple access channel (MAC) in that the two users also receive channel outputs. It is assume...

In this work, we investigate two source coding models, a Helper problem and a Gray-Wyner problem, under equivocation constraints. Specifically, in the Helper problem, an encoder communicates with a legitimate receiver through a noise-free rate-limited public link as well as a noise-free rate-limited private link; and an external passive eavesdropper intercepts every information that is sent on ...

In this paper, inner and outer bounds on the capacity region of two-user interference channels with two confidential messages have been proposed. By adding secure multiplex coding to the error correction method in [15] which achieves the best achievable capacity region for interference channel up to now, we have shown that the improved secure capacity region compared with [2] now is the whole H...

Absrfucr-Given two discrete memoryless channels @MC’s) with a common input, it is desired to transmit private messagea to receiver 1 at r&R, andcommon meswgea to both receivers at rate R,, while keeping receiver 2 as ignorant of tbe private messages as possible. Measurhg ignorance by equivocation, a single-letter characterization is given of the. achievable trfplea (RI&R,-,) where 4 is the equi...

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...

We treat secret key extraction when the eavesdropper has correlated quantum states. We propose quantum privacy amplification theorems different from Renner’s, which are based on quantum conditional Rényi entropy of order 1 + s. Using those theorems, we derive an exponential decreasing rate for leaked information and the asymptotic equivocation rate.