Signal Recovery from Random Dot-Product Graphs Under Local Differential Privacy
Siddharth Vishwanath, Jonathan Hehir
TL;DR
This work addresses recovering latent positions in generalized random dot-product graphs under $\varepsilon$-edge local differential privacy. It shows that the edgeFlip privacy mechanism induces a tractable geometric distortion captured by an affine map $\varphi_\varepsilon$, enabling a privacy-aware inference pipeline based on a privacy-adjusted spectral embedding. The authors establish a minimax lower bound for latent-position estimation under $\varepsilon$-edge LDP and demonstrate that their embedding achieves near-minimax rates in dense regimes, up to a $\sqrt{\log n}$ factor; they also extend the analysis to topological inference using persistence diagrams, showing consistent recovery of underlying geometry and topology. The results generalize private community-detection insights to the richer GRDPG framework and provide practical tools for geometry- and topology-based analysis of privatized networks.
Abstract
We consider the problem of recovering latent information from graphs under $\varepsilon$-edge local differential privacy where the presence of relationships/edges between two users/vertices remains confidential, even from the data curator. For the class of generalized random dot-product graphs, we show that a standard local differential privacy mechanism induces a specific geometric distortion in the latent positions. Leveraging this insight, we show that consistent recovery of the latent positions is achievable by appropriately adjusting the statistical inference procedure for the privatized graph. Furthermore, we prove that our procedure is nearly minimax-optimal under local edge differential privacy constraints. Lastly, we show that this framework allows for consistent recovery of geometric and topological information underlying the latent positions, as encoded in their persistence diagrams. Our results extend previous work from the private community detection literature to a substantially richer class of models and inferential tasks.
