Cooperative encoding for secrecy in interference channels

TL;DR

This paper explores the limits of secure communication in a two-user interference channel with an eavesdropper, proposing a cooperative encoding scheme that enhances secrecy capacity by jointly designing codebooks and optimizing channel prefixing.

Contribution

It introduces a novel cooperative encoding strategy with message-splitting for interference channels, establishing inner and outer bounds and demonstrating optimality in certain cases.

Findings

The proposed scheme improves secrecy capacity in interference channels.

In the Gaussian case, the approach generalizes existing cooperative jamming techniques.

Structural insights reveal how interference can be exploited for increased secrecy.

Abstract

This paper investigates the fundamental performance limits of the two-user interference channel in the presence of an external eavesdropper. In this setting, we construct an inner bound, to the secrecy capacity region, based on the idea of cooperative encoding in which the two users cooperatively design their randomized codebooks and jointly optimize their channel prefixing distributions. Our achievability scheme also utilizes message-splitting in order to allow for partial decoding of the interference at the non-intended receiver. Outer bounds are then derived and used to establish the optimality of the proposed scheme in certain cases. In the Gaussian case, the previously proposed cooperative jamming and noise-forwarding techniques are shown to be special cases of our proposed approach. Overall, our results provide structural insights on how the interference can be exploited to increase the secrecy capacity of wireless networks.