Secrecy Results for Compound Wiretap Channels

TL;DR

This paper establishes the secrecy capacity bounds for compound wiretap channels with and without channel state information, providing a full coding theorem and addressing decoding robustness under strong secrecy criteria.

Contribution

It derives matching lower and upper bounds for the secrecy capacity with channel state information and presents a multi-letter capacity expression without it, advancing theoretical understanding.

Findings

Matching lower and upper bounds for secrecy capacity with CSI

A multi-letter expression for capacity without CSI

Robust decoding scheme against randomisation effects

Abstract

We derive a lower bound on the secrecy capacity of the compound wiretap channel with channel state information at the transmitter which matches the general upper bound on the secrecy capacity of general compound wiretap channels given by Liang et al. and thus establishing a full coding theorem in this case. We achieve this with a stronger secrecy criterion and the maximum error probability criterion, and with a decoder that is robust against the effect of randomisation in the encoding. This relieves us from the need of decoding the randomisation parameter which is in general not possible within this model. Moreover we prove a lower bound on the secrecy capacity of the compound wiretap channel without channel state information and derive a multi-letter expression for the capacity in this communication scenario.