A rechargeable battery may be used to partially protect the privacy of information contained in a household’s electrical load profile. We represent the system as a finite state model to make tractable the computation of the rate of information leakage. Specifically, we use a trellis algorithm to estimate the mutual information rate between the battery’s input and output loads. We show that stochastic battery policies can leak 26% less information than a so-called best-effort algorithm (that holds the output load constant whenever possible). We finally describe the extension of the technique to more realistic models of the battery system.
David P. Varodayan, Ashish Khisti