Secret Key Agreement Using Conferencing in State- Dependent Multiple Access Channels with An Eavesdropper

TL;DR

This paper investigates secret key agreement in state-dependent multiple access channels with an eavesdropper, considering non-causal channel state information, limited conferencing, and public communication, deriving bounds and capacities for common and private keys.

Contribution

It introduces new bounds and capacity results for secret key sharing in complex multi-user, state-dependent channels with conferencing and public channels.

Findings

Established lower and upper bounds on common key capacity.

Derived inner and outer bounds on private key capacity region.

Identified special cases where bounds coincide and capacity is exactly known.

Abstract

In this paper, the problem of secret key agreement in state-dependent multiple access channels with an eavesdropper is studied. For this model, the channel state information is non-causally available at the transmitters; furthermore, a legitimate receiver observes a degraded version of the channel state information. The transmitters can partially cooperate with each other using a conferencing link with a limited rate. In addition, a backward public channel is assumed between the terminals. The problem of secret key sharing consists of two rounds. In the first round, the transmitters wish to share a common key with the legitimate receiver. Lower and upper bounds on the common key capacity are established. In a special case, the capacity of the common key is obtained. In the second round, the legitimate receiver agrees on two independent private keys with the corresponding transmitters using the public channel. Inner and outer bounds on the private key capacity region are characterized. In a special case, the inner bound coincides with the outer bound. We provide some examples to illustrate our results.