Faster Differentially Private Top-$k$ Selection: A Joint Exponential Mechanism with Pruning

Fuente: arXiv
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Auteurs principaux: WU, Hao, Zhang, Hanwen
Format: Preprint
Publié: 2024
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author WU, Hao
Zhang, Hanwen
author_facet WU, Hao
Zhang, Hanwen
contents We study the differentially private top-$k$ selection problem, aiming to identify a sequence of $k$ items with approximately the highest scores from $d$ items. Recent work by Gillenwater et al. (ICML '22) employs a direct sampling approach from the vast collection of $d^{\,Θ(k)}$ possible length-$k$ sequences, showing superior empirical accuracy compared to previous pure or approximate differentially private methods. Their algorithm has a time and space complexity of $\tilde{O}(dk)$. In this paper, we present an improved algorithm with time and space complexity $O(d + k^2 / ε\cdot \ln d)$, where $ε$ denotes the privacy parameter. Experimental results show that our algorithm runs orders of magnitude faster than their approach, while achieving similar empirical accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2411_09552
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Faster Differentially Private Top-$k$ Selection: A Joint Exponential Mechanism with Pruning
WU, Hao
Zhang, Hanwen
Cryptography and Security
We study the differentially private top-$k$ selection problem, aiming to identify a sequence of $k$ items with approximately the highest scores from $d$ items. Recent work by Gillenwater et al. (ICML '22) employs a direct sampling approach from the vast collection of $d^{\,Θ(k)}$ possible length-$k$ sequences, showing superior empirical accuracy compared to previous pure or approximate differentially private methods. Their algorithm has a time and space complexity of $\tilde{O}(dk)$. In this paper, we present an improved algorithm with time and space complexity $O(d + k^2 / ε\cdot \ln d)$, where $ε$ denotes the privacy parameter. Experimental results show that our algorithm runs orders of magnitude faster than their approach, while achieving similar empirical accuracy.
title Faster Differentially Private Top-$k$ Selection: A Joint Exponential Mechanism with Pruning
topic Cryptography and Security
url https://arxiv.org/abs/2411.09552