PREAMBLE: Private and Efficient Aggregation via Block Sparse Vectors

Fuente: arXiv
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Main Authors: Asi, Hilal, Feldman, Vitaly, Keller, Hannah, Rothblum, Guy N., Talwar, Kunal
Format: Preprint
Published: 2025
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author Asi, Hilal
Feldman, Vitaly
Keller, Hannah
Rothblum, Guy N.
Talwar, Kunal
author_facet Asi, Hilal
Feldman, Vitaly
Keller, Hannah
Rothblum, Guy N.
Talwar, Kunal
contents We revisit the problem of secure aggregation of high-dimensional vectors in a two-server system such as Prio. These systems are typically used to aggregate vectors such as gradients in private federated learning, where the aggregate itself is protected via noise addition to ensure differential privacy. Existing approaches require communication scaling with the dimensionality, and thus limit the dimensionality of vectors one can efficiently process in this setup. We propose PREAMBLE: {\bf Pr}ivate {\bf E}fficient {\bf A}ggregation {\bf M}echanism via {\bf BL}ock-sparse {\bf E}uclidean Vectors. PREAMBLE builds on an extension of distributed point functions that enables communication- and computation-efficient aggregation of {\em block-sparse vectors}, which are sparse vectors where the non-zero entries occur in a small number of clusters of consecutive coordinates. We show that these block-sparse DPFs can be combined with random sampling and privacy amplification by sampling results, to allow asymptotically optimal privacy-utility trade-offs for vector aggregation, at a fraction of the communication cost. When coupled with recent advances in numerical privacy accounting, our approach incurs a negligible overhead in noise variance, compared to the Gaussian mechanism used with Prio.
format Preprint
id arxiv_https___arxiv_org_abs_2503_11897
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle PREAMBLE: Private and Efficient Aggregation via Block Sparse Vectors
Asi, Hilal
Feldman, Vitaly
Keller, Hannah
Rothblum, Guy N.
Talwar, Kunal
Cryptography and Security
Data Structures and Algorithms
Machine Learning
We revisit the problem of secure aggregation of high-dimensional vectors in a two-server system such as Prio. These systems are typically used to aggregate vectors such as gradients in private federated learning, where the aggregate itself is protected via noise addition to ensure differential privacy. Existing approaches require communication scaling with the dimensionality, and thus limit the dimensionality of vectors one can efficiently process in this setup. We propose PREAMBLE: {\bf Pr}ivate {\bf E}fficient {\bf A}ggregation {\bf M}echanism via {\bf BL}ock-sparse {\bf E}uclidean Vectors. PREAMBLE builds on an extension of distributed point functions that enables communication- and computation-efficient aggregation of {\em block-sparse vectors}, which are sparse vectors where the non-zero entries occur in a small number of clusters of consecutive coordinates. We show that these block-sparse DPFs can be combined with random sampling and privacy amplification by sampling results, to allow asymptotically optimal privacy-utility trade-offs for vector aggregation, at a fraction of the communication cost. When coupled with recent advances in numerical privacy accounting, our approach incurs a negligible overhead in noise variance, compared to the Gaussian mechanism used with Prio.
title PREAMBLE: Private and Efficient Aggregation via Block Sparse Vectors
topic Cryptography and Security
Data Structures and Algorithms
Machine Learning
url https://arxiv.org/abs/2503.11897