Mitigating Privacy-Utility Trade-off in Decentralized Federated Learning via $f$-Differential Privacy

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Li, Xiang, Su, Buxin, Wang, Chendi, Long, Qi, Su, Weijie J.
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866909864634089472
author Li, Xiang
Su, Buxin
Wang, Chendi
Long, Qi
Su, Weijie J.
author_facet Li, Xiang
Su, Buxin
Wang, Chendi
Long, Qi
Su, Weijie J.
contents Differentially private (DP) decentralized Federated Learning (FL) allows local users to collaborate without sharing their data with a central server. However, accurately quantifying the privacy budget of private FL algorithms is challenging due to the co-existence of complex algorithmic components such as decentralized communication and local updates. This paper addresses privacy accounting for two decentralized FL algorithms within the $f$-differential privacy ($f$-DP) framework. We develop two new $f$-DP-based accounting methods tailored to decentralized settings: Pairwise Network $f$-DP (PN-$f$-DP), which quantifies privacy leakage between user pairs under random-walk communication, and Secret-based $f$-Local DP (Sec-$f$-LDP), which supports structured noise injection via shared secrets. By combining tools from $f$-DP theory and Markov chain concentration, our accounting framework captures privacy amplification arising from sparse communication, local iterations, and correlated noise. Experiments on synthetic and real datasets demonstrate that our methods yield consistently tighter $(ε,δ)$ bounds and improved utility compared to Rényi DP-based approaches, illustrating the benefits of $f$-DP in decentralized privacy accounting.
format Preprint
id arxiv_https___arxiv_org_abs_2510_19934
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mitigating Privacy-Utility Trade-off in Decentralized Federated Learning via $f$-Differential Privacy
Li, Xiang
Su, Buxin
Wang, Chendi
Long, Qi
Su, Weijie J.
Machine Learning
Cryptography and Security
Statistics Theory
Methodology
Differentially private (DP) decentralized Federated Learning (FL) allows local users to collaborate without sharing their data with a central server. However, accurately quantifying the privacy budget of private FL algorithms is challenging due to the co-existence of complex algorithmic components such as decentralized communication and local updates. This paper addresses privacy accounting for two decentralized FL algorithms within the $f$-differential privacy ($f$-DP) framework. We develop two new $f$-DP-based accounting methods tailored to decentralized settings: Pairwise Network $f$-DP (PN-$f$-DP), which quantifies privacy leakage between user pairs under random-walk communication, and Secret-based $f$-Local DP (Sec-$f$-LDP), which supports structured noise injection via shared secrets. By combining tools from $f$-DP theory and Markov chain concentration, our accounting framework captures privacy amplification arising from sparse communication, local iterations, and correlated noise. Experiments on synthetic and real datasets demonstrate that our methods yield consistently tighter $(ε,δ)$ bounds and improved utility compared to Rényi DP-based approaches, illustrating the benefits of $f$-DP in decentralized privacy accounting.
title Mitigating Privacy-Utility Trade-off in Decentralized Federated Learning via $f$-Differential Privacy
topic Machine Learning
Cryptography and Security
Statistics Theory
Methodology
url https://arxiv.org/abs/2510.19934