Saved in:
Bibliographic Details
Main Authors: Takagi, Shun, Liew, Seng Pei
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2604.28032
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866917451276484608
author Takagi, Shun
Liew, Seng Pei
author_facet Takagi, Shun
Liew, Seng Pei
contents We study $d$-dimensional unbiased mean estimation in the single-message shuffle model, where each user sends a single privatized message and the analyzer only observes the shuffled multiset of reports. While minimax-optimal mechanisms are well understood in the local differential privacy setting, the corresponding notion of optimality after shuffling has remained largely unexplored. To address this gap, we introduce the recently proposed shuffle index and use it to formulate the post-shuffling mechanism design problem as an explicit optimization problem. We then establish a minimax lower bound on the achievable mean squared error in terms of the shuffle index, which implies that mechanisms that are optimal under LDP can become suboptimal once shuffling is applied. Finally, we construct an asymptotically minimax optimal mechanism in the high privacy regime, which as a consequence achieves a privacy-utility trade-off nearly identical to that of the central Gaussian mechanism.
format Preprint
id arxiv_https___arxiv_org_abs_2604_28032
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Shuffling-Aware Optimization for Private Vector Mean Estimation
Takagi, Shun
Liew, Seng Pei
Machine Learning
We study $d$-dimensional unbiased mean estimation in the single-message shuffle model, where each user sends a single privatized message and the analyzer only observes the shuffled multiset of reports. While minimax-optimal mechanisms are well understood in the local differential privacy setting, the corresponding notion of optimality after shuffling has remained largely unexplored. To address this gap, we introduce the recently proposed shuffle index and use it to formulate the post-shuffling mechanism design problem as an explicit optimization problem. We then establish a minimax lower bound on the achievable mean squared error in terms of the shuffle index, which implies that mechanisms that are optimal under LDP can become suboptimal once shuffling is applied. Finally, we construct an asymptotically minimax optimal mechanism in the high privacy regime, which as a consequence achieves a privacy-utility trade-off nearly identical to that of the central Gaussian mechanism.
title Shuffling-Aware Optimization for Private Vector Mean Estimation
topic Machine Learning
url https://arxiv.org/abs/2604.28032