In plain words: A privacy system answering many questions about a dataset adds a capped amount of random noise to each answer, so errors never exceed a set limit. It matches the best possible privacy-accuracy tradeoff and beats the usual unbounded bell-curve noise in many cases.
Abstract
We present an asymptotically optimal $(ε,δ)$ differentially private mechanism for answering multiple, adaptively asked, $Δ$-sensitive queries, settling the conjecture of Steinke and Ullman [2020]. Our algorithm has a significant advantage that it adds independent bounded noise to each query, thus providing an absolute error bound. Additionally, we apply our algorithm in adaptive data analysis, obtaining an improved guarantee for answering multiple queries regarding some underlying distribution using a finite sample. Numerical computations show that the bounded-noise mechanism outperforms the Gaussian mechanism in many standard settings.
Yuval Dagan, Gil Kur
arXiv:2012.03817 · cs.DS, cs.CR, cs.LG · submitted Dec 7, 2020 · updated Nov 7, 2021
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