Capacity results for compound wiretap channels

TL;DR

This paper establishes the exact secrecy capacity for compound wiretap channels with channel state information at the transmitter, using a strong secrecy criterion and a robust decoding scheme, and also provides bounds without channel state information.

Contribution

It provides a full coding theorem for the secrecy capacity of compound wiretap channels with channel state information, matching known upper bounds and introducing a robust decoding approach.

Findings

Derived a matching lower bound on secrecy capacity with CSI

Proved a lower bound on secrecy capacity without CSI

Established a full coding theorem for the model

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 quite strong secrecy 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.