Private and Continual Release of Statistics

We ask the question – how can websites and data aggregators continually release updated statistics, and meanwhile preserve each individual user’s privacy? Given a stream of 0’s and 1’s, we propose a differentially private continual counter that outputs at every time step the approximate number of 1’s 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 websites to continually give top-k and hot items suggestions while preserving users’ privacy.