2026-07-24T05:17:06Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:12119 2024-03-06T10:49:34Z ddc:004 open_access

The Power of Synergy in Differential Privacy: Combining a Small Curator with Local Randomizers Beimel, Amos Korolova, Aleksandra Nissim, Kobbi Sheffet, Or Stemmer, Uri differential privacy hybrid model private learning local model Motivated by the desire to bridge the utility gap between local and trusted curator models of differential privacy for practical applications, we initiate the theoretical study of a hybrid model introduced by "Blender" [Avent et al., USENIX Security '17], in which differentially private protocols of n agents that work in the local-model are assisted by a differentially private curator that has access to the data of m additional users. We focus on the regime where m ≪ n and study the new capabilities of this (m,n)-hybrid model. We show that, despite the fact that the hybrid model adds no significant new capabilities for the basic task of simple hypothesis-testing, there are many other tasks (under a wide range of parameters) that can be solved in the hybrid model yet cannot be solved either by the curator or by the local-users separately. Moreover, we exhibit additional tasks where at least one round of interaction between the curator and the local-users is necessary - namely, no hybrid model protocol without such interaction can solve these tasks. Taken together, our results show that the combination of the local model with a small curator can become part of a promising toolkit for designing and implementing differential privacy. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Amos Beimel and Aleksandra Korolova and Kobbi Nissim and Or Sheffet and Uri Stemmer 2020 Is Part Of LIPIcs, Volume 163, 1st Conference on Information-Theoretic Cryptography (ITC 2020) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.ITC.2020.14 urn:nbn:de:0030-drops-121195 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITC.2020.14 eng https://creativecommons.org/licenses/by/3.0/legalcode