Information-Theoretical Security for Several Models of Multiple-Access Channel

TL;DR

This paper investigates information-theoretical security in multiple-access channels, deriving capacity-equivocation regions for various models including degraded and wiretap channels, with concrete binary and Gaussian examples.

Contribution

It introduces new capacity-equivocation bounds for degraded and wiretap MAC models, including cooperative and non-cooperative encoder scenarios.

Findings

Capacity-equivocation region bounds for degraded MAC with confidential messages

Exact capacity-equivocation region for cooperative MAC-WT

Inner and outer bounds for non-cooperative MAC-WT

Abstract

Several security models of multiple-access channel (MAC) are investigated. First, we study the degraded MAC with confidential messages, where two users transmit their confidential messages (no common message) to a destination, and each user obtains a degraded version of the output of the MAC. Each user views the other user as a eavesdropper, and wishes to keep its confidential message as secret as possible from the other user. Measuring each user's uncertainty about the other user's confidential message by equivocation, the inner and outer bounds on the capacity-equivocation region for this model have been provided. The result is further explained via the binary and Gaussian examples. Second, the discrete memoryless multiple-access wiretap channel (MAC-WT) is studied, where two users transmit their corresponding confidential messages (no common message) to a legitimate receiver, while an additional wiretapper wishes to obtain the messages via a wiretap channel. This new model is considered into two cases: the general MAC-WT with cooperative encoders, and the degraded MAC-WT with non-cooperative encoders. The capacity-equivocation region is totally determined for the cooperative case, and inner and outer bounds on the capacity-equivocation region are provided for the non-cooperative case. For both cases, the results are further explained via the binary examples.