Poster
DP-PCA: Statistically Optimal and Differentially Private PCA
Xiyang Liu · Weihao Kong · Prateek Jain · Sewoong Oh
Hall J (level 1) #538
Keywords: [ private estimation ] [ differential privacy ] [ principal component analysis ]
Abstract:
We study the canonical statistical task of computing the principal component from i.i.d.~data under differential privacy. Although extensively studied in literature, existing solutions fall short on two key aspects: (i) even for Gaussian data, existing private algorithms require the number of samples n to scale super-linearly with d, i.e., n=Ω(d3/2), to obtain non-trivial results while non-private PCA requires only n=O(d), and (ii) existing techniques suffer from a large error even when the variance in each data point is small. We propose DP-PCA method that uses a single-pass minibatch gradient descent style algorithm to overcome the above limitations. For sub-Gaussian data, we provide nearly optimal statistical error rates even for n=O(dlogd).
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