PrivShape: Extracting Shapes in Time Series under User-Level Local Differential Privacy

Fuente: arXiv
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Main Authors: Mao, Yulian, Ye, Qingqing, Hu, Haibo, Wang, Qi, Huang, Kai
Format: Preprint
Published: 2024
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author Mao, Yulian
Ye, Qingqing
Hu, Haibo
Wang, Qi
Huang, Kai
author_facet Mao, Yulian
Ye, Qingqing
Hu, Haibo
Wang, Qi
Huang, Kai
contents Time series have numerous applications in finance, healthcare, IoT, and smart city. In many of these applications, time series typically contain personal data, so privacy infringement may occur if they are released directly to the public. Recently, local differential privacy (LDP) has emerged as the state-of-the-art approach to protecting data privacy. However, existing works on LDP-based collections cannot preserve the shape of time series. A recent work, PatternLDP, attempts to address this problem, but it can only protect a finite group of elements in a time series due to ω-event level privacy guarantee. In this paper, we propose PrivShape, a trie-based mechanism under user-level LDP to protect all elements. PrivShape first transforms a time series to reduce its length, and then adopts trie-expansion and two-level refinement to improve utility. By extensive experiments on real-world datasets, we demonstrate that PrivShape outperforms PatternLDP when adapted for offline use, and can effectively extract frequent shapes.
format Preprint
id arxiv_https___arxiv_org_abs_2404_03873
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle PrivShape: Extracting Shapes in Time Series under User-Level Local Differential Privacy
Mao, Yulian
Ye, Qingqing
Hu, Haibo
Wang, Qi
Huang, Kai
Cryptography and Security
Time series have numerous applications in finance, healthcare, IoT, and smart city. In many of these applications, time series typically contain personal data, so privacy infringement may occur if they are released directly to the public. Recently, local differential privacy (LDP) has emerged as the state-of-the-art approach to protecting data privacy. However, existing works on LDP-based collections cannot preserve the shape of time series. A recent work, PatternLDP, attempts to address this problem, but it can only protect a finite group of elements in a time series due to ω-event level privacy guarantee. In this paper, we propose PrivShape, a trie-based mechanism under user-level LDP to protect all elements. PrivShape first transforms a time series to reduce its length, and then adopts trie-expansion and two-level refinement to improve utility. By extensive experiments on real-world datasets, we demonstrate that PrivShape outperforms PatternLDP when adapted for offline use, and can effectively extract frequent shapes.
title PrivShape: Extracting Shapes in Time Series under User-Level Local Differential Privacy
topic Cryptography and Security
url https://arxiv.org/abs/2404.03873