The Correlated Gaussian Sparse Histogram Mechanism

Fuente: arXiv
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Main Authors: Lebeda, Christian Janos, Retschmeier, Lukas
Format: Preprint
Published: 2024
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author Lebeda, Christian Janos
Retschmeier, Lukas
author_facet Lebeda, Christian Janos
Retschmeier, Lukas
contents We consider the problem of releasing a sparse histogram under $(\varepsilon, δ)$-differential privacy. The stability histogram independently adds noise from a Laplace or Gaussian distribution to the non-zero entries and removes those noisy counts below a threshold. Thereby, the introduction of new non-zero values between neighboring histograms is only revealed with probability at most $δ$, and typically, the value of the threshold dominates the error of the mechanism. We consider the variant of the stability histogram with Gaussian noise. Recent works ([Joseph and Yu, COLT '24] and [Lebeda, SOSA '25]) reduced the error for private histograms using correlated Gaussian noise. However, these techniques can not be directly applied in the very sparse setting. Instead, we adopt Lebeda's technique and show that adding correlated noise to the non-zero counts only allows us to reduce the magnitude of noise when we have a sparsity bound. This, in turn, allows us to use a lower threshold by up to a factor of $1/2$ compared to the non-correlated noise mechanism. We then extend our mechanism to a setting without a known bound on sparsity. Additionally, we show that correlated noise can give a similar improvement for the more practical discrete Gaussian mechanism.
format Preprint
id arxiv_https___arxiv_org_abs_2412_10357
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Correlated Gaussian Sparse Histogram Mechanism
Lebeda, Christian Janos
Retschmeier, Lukas
Data Structures and Algorithms
Cryptography and Security
Machine Learning
We consider the problem of releasing a sparse histogram under $(\varepsilon, δ)$-differential privacy. The stability histogram independently adds noise from a Laplace or Gaussian distribution to the non-zero entries and removes those noisy counts below a threshold. Thereby, the introduction of new non-zero values between neighboring histograms is only revealed with probability at most $δ$, and typically, the value of the threshold dominates the error of the mechanism. We consider the variant of the stability histogram with Gaussian noise. Recent works ([Joseph and Yu, COLT '24] and [Lebeda, SOSA '25]) reduced the error for private histograms using correlated Gaussian noise. However, these techniques can not be directly applied in the very sparse setting. Instead, we adopt Lebeda's technique and show that adding correlated noise to the non-zero counts only allows us to reduce the magnitude of noise when we have a sparsity bound. This, in turn, allows us to use a lower threshold by up to a factor of $1/2$ compared to the non-correlated noise mechanism. We then extend our mechanism to a setting without a known bound on sparsity. Additionally, we show that correlated noise can give a similar improvement for the more practical discrete Gaussian mechanism.
title The Correlated Gaussian Sparse Histogram Mechanism
topic Data Structures and Algorithms
Cryptography and Security
Machine Learning
url https://arxiv.org/abs/2412.10357