Secure Hybrid Digital-Analog Coding With Side Information at the Receiver

TL;DR

This paper investigates secure transmission of Gaussian sources over wiretap channels with receiver side information, proposing hybrid digital-analog coding schemes that achieve minimal distortion and exhibit graceful SNR mismatch degradation.

Contribution

It introduces secure hybrid digital-analog Wyner-Ziv coding schemes that are optimal for minimizing distortion and robust under SNR mismatch, advancing secure joint source-channel coding.

Findings

Source-channel separation coding is optimal for minimum distortion.

Proposed hybrid schemes achieve minimal distortion.

Schemes degrade gracefully under SNR mismatch.

Abstract

In this work, the problem of transmitting an i.i.d Gaussian source over an i.i.d Gaussian wiretap channel with an i.i.d Gaussian side information available at the intended receiver is considered. The intended receiver is assumed to have a certain minimum SNR and the eavesdropper is assumed to have a strictly lower SNR, compared to the intended receiver. The objective is to minimize the distortion of source reconstruction at the intended receiver. In this work, it is shown that the source-channel separation coding scheme is optimum in the sense of achieving minimum distortion. Two hybrid digital-analog Wyner-Ziv coding schemes are then proposed which achieve the minimum distortion. These secure joint source-channel coding schemes are based on the Wyner-Ziv coding scheme and wiretap channel coding scheme when the analog source is not explicitly quantized. The proposed secure hybrid digital-analog schemes are analyzed under the main channel SNR mismatch. It is proven that the proposed schemes can give a graceful degradation of distortion with SNR under SNR mismatch, i.e., when the actual SNR is larger than the designed SNR.