Discriminatory Lossy Source Coding: Side Information Privacy

TL;DR

This paper investigates lossy source coding with privacy constraints on side information, characterizing feasible rate-distortion-equivocation trade-offs for scenarios with and without encoder side information.

Contribution

It provides a complete characterization of rate-distortion-equivocation regions for both informed and uninformed encoder cases, highlighting privacy benefits of encoder side information.

Findings

Encoder side information enhances privacy by increasing equivocation.

Explicit rate-distortion-equivocation regions are derived for binary symmetric sources.

The advantage of encoder side information is demonstrated through specific source and distortion models.

Abstract

A lossy source coding problem is studied in which a source encoder communicates with two decoders, one with and one without correlated side information with an additional constraint on the privacy of the side information at the uninformed decoder. Two cases of this problem arise depending on the availability of the side information at the encoder. The set of all feasible rate-distortion-equivocation tuples are characterized for both cases. The difference between the informed and uninformed cases and the advantages of encoder side information for enhancing privacy are highlighted for a binary symmetric source with erasure side information and Hamming distortion.