Private and continual release of statistics

Abstract

We ask the question: how can Web sites and data aggregators continually release updated statistics, and meanwhile preserve each individual users privacy? Suppose we are given a stream of 0s and 1s. We propose a differentially private continual counter that outputs at every time step the approximate number of 1s seen thus far. Our counter construction has error that is only poly-log in the number of time steps. We can extend the basic counter construction to allow Web sites to continually give top-k and hot items suggestions while preserving users privacy.