Linear-Time User-Level DP-SCO via Robust Statistics

Fuente: arXiv
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Main Authors: Ghazi, Badih, Kumar, Ravi, Liu, Daogao, Manurangsi, Pasin
Format: Preprint
Published: 2025
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author Ghazi, Badih
Kumar, Ravi
Liu, Daogao
Manurangsi, Pasin
author_facet Ghazi, Badih
Kumar, Ravi
Liu, Daogao
Manurangsi, Pasin
contents User-level differentially private stochastic convex optimization (DP-SCO) has garnered significant attention due to the paramount importance of safeguarding user privacy in modern large-scale machine learning applications. Current methods, such as those based on differentially private stochastic gradient descent (DP-SGD), often struggle with high noise accumulation and suboptimal utility due to the need to privatize every intermediate iterate. In this work, we introduce a novel linear-time algorithm that leverages robust statistics, specifically the median and trimmed mean, to overcome these challenges. Our approach uniquely bounds the sensitivity of all intermediate iterates of SGD with gradient estimation based on robust statistics, thereby significantly reducing the gradient estimation noise for privacy purposes and enhancing the privacy-utility trade-off. By sidestepping the repeated privatization required by previous methods, our algorithm not only achieves an improved theoretical privacy-utility trade-off but also maintains computational efficiency. We complement our algorithm with an information-theoretic lower bound, showing that our upper bound is optimal up to logarithmic factors and the dependence on $ε$. This work sets the stage for more robust and efficient privacy-preserving techniques in machine learning, with implications for future research and application in the field.
format Preprint
id arxiv_https___arxiv_org_abs_2502_08889
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Linear-Time User-Level DP-SCO via Robust Statistics
Ghazi, Badih
Kumar, Ravi
Liu, Daogao
Manurangsi, Pasin
Machine Learning
Cryptography and Security
Data Structures and Algorithms
User-level differentially private stochastic convex optimization (DP-SCO) has garnered significant attention due to the paramount importance of safeguarding user privacy in modern large-scale machine learning applications. Current methods, such as those based on differentially private stochastic gradient descent (DP-SGD), often struggle with high noise accumulation and suboptimal utility due to the need to privatize every intermediate iterate. In this work, we introduce a novel linear-time algorithm that leverages robust statistics, specifically the median and trimmed mean, to overcome these challenges. Our approach uniquely bounds the sensitivity of all intermediate iterates of SGD with gradient estimation based on robust statistics, thereby significantly reducing the gradient estimation noise for privacy purposes and enhancing the privacy-utility trade-off. By sidestepping the repeated privatization required by previous methods, our algorithm not only achieves an improved theoretical privacy-utility trade-off but also maintains computational efficiency. We complement our algorithm with an information-theoretic lower bound, showing that our upper bound is optimal up to logarithmic factors and the dependence on $ε$. This work sets the stage for more robust and efficient privacy-preserving techniques in machine learning, with implications for future research and application in the field.
title Linear-Time User-Level DP-SCO via Robust Statistics
topic Machine Learning
Cryptography and Security
Data Structures and Algorithms
url https://arxiv.org/abs/2502.08889