Feedback-Based Collaborative Secrecy Encoding over Binary Symmetric Channels

TL;DR

This paper introduces a feedback-based encoding scheme for secure communication over binary symmetric channels, which improves secrecy rates and can achieve positive secrecy even when the eavesdropper's channel is better.

Contribution

It presents a novel feedback-based encoding method that enhances secrecy capacity and combines with existing schemes for improved secure communication.

Findings

Achieves larger rate-equivocation regions than Wyner's scheme.

Secures positive secrecy rates even when eavesdropper's channel is less noisy.

Demonstrates significant improvements in various configurations.

Abstract

In this paper we propose a feedback scheme for transmitting secret messages between two legitimate parties, over an eavesdropped communication link. Relative to Wyner's traditional encoding scheme \cite{wyner1}, our feedback-based encoding often yields larger rate-equivocation regions and achievable secrecy rates. More importantly, by exploiting the channel randomness inherent in the feedback channels, our scheme achieves a strictly positive secrecy rate even when the eavesdropper's channel is less noisy than the legitimate receiver's channel. All channels are modeled as binary and symmetric (BSC). We demonstrate the versatility of our feedback-based encoding method by using it in three different configurations: the stand-alone configuration, the mixed configuration (when it combines with Wyner's scheme \cite{wyner1}), and the reversed configuration. Depending on the channel conditions, significant improvements over Wyner's secrecy capacity can be observed in all configurations.