Testing Against Independence with an Eavesdropper

Abstract

We study a distributed binary hypothesis testing (HT) problem with communication and security constraints, involving three parties: a remote sensor called Alice, a legitimate decision center called Bob, and an eavesdropper called Eve, all having their own source observations. In this system, Alice conveys a rate-R description of her observations to Bob, and Bob performs a binary hypothesis test on the joint distribution underlying his and Alice’s observations. The goal of Alice and Bob is to maximize the exponential decay of Bob’s miss-detection (type-II error) probability under two constraints: Bob’s false-alarm (type-I error) probability has to stay below a given threshold and Eve’s uncertainty (equivocation) about Alice’s observations should stay above a given security threshold even when Eve learns Alice’s message. For the special case of testing against independence, we characterize the largest possible type-II error exponent under the described type-I error probability and security constraints.