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CoinPress: Practical Private Mean and Covariance Estimation

Machine Learning 2026-02-10 v3 Cryptography and Security Data Structures and Algorithms Information Theory Machine Learning math.IT Statistics Theory Statistics Theory

Abstract

We present simple differentially private estimators for the mean and covariance of multivariate sub-Gaussian data that are accurate at small sample sizes. We demonstrate the effectiveness of our algorithms both theoretically and empirically using synthetic and real-world datasets -- showing that their asymptotic error rates match the state-of-the-art theoretical bounds, and that they concretely outperform all previous methods. Specifically, previous estimators either have weak empirical accuracy at small sample sizes, perform poorly for multivariate data, or require the user to provide strong a priori estimates for the parameters.

Keywords

Cite

@article{arxiv.2006.06618,
  title  = {CoinPress: Practical Private Mean and Covariance Estimation},
  author = {Sourav Biswas and Yihe Dong and Gautam Kamath and Jonathan Ullman},
  journal= {arXiv preprint arXiv:2006.06618},
  year   = {2026}
}

Comments

Code is available at https://github.com/twistedcubic/coin-press. Experimental results were inadvertently commented out of previous version

R2 v1 2026-06-23T16:14:47.368Z