STAR: Secret Sharing for Private Threshold Aggregation Reporting
This work addresses the challenge of scalable and cost-effective privacy-preserving data collection for developers, representing a significant practical improvement over existing methods.
The authors tackled the problem of impractical private threshold aggregation reporting systems by proposing STAR, a highly efficient and deployable system that provides cryptographically-enforced k-anonymity, resulting in a 1773x speed improvement, 62.4x less communication, and 24x lower cost compared to the state-of-the-art.
Threshold aggregation reporting systems promise a practical, privacy-preserving solution for developers to learn how their applications are used "\emph{in-the-wild}". Unfortunately, proposed systems to date prove impractical for wide scale adoption, suffering from a combination of requiring: \emph{i)} prohibitive trust assumptions; \emph{ii)} high computation costs; or \emph{iii)} massive user bases. As a result, adoption of truly-private approaches has been limited to only a small number of enormous (and enormously costly) projects. In this work, we improve the state of private data collection by proposing $\mathsf{STAR}$, a highly efficient, easily deployable system for providing cryptographically-enforced $κ$-anonymity protections on user data collection. The $\mathsf{STAR}$ protocol is easy to implement and cheap to run, all while providing privacy properties similar to, or exceeding the current state-of-the-art. Measurements of our open-source implementation of $\mathsf{STAR}$ find that it is $1773\times$ quicker, requires $62.4\times$ less communication, and is $24\times$ cheaper to run than the existing state-of-the-art.