Anunay Kulshrestha will present his FPO "Advancing Public Policy Through Cryptography: Building Private and Accountable Systems" on Friday, June 20, 2025 at 11am in Sherrerd 308 (CITP Conference Room) and Zoom. Zoom: https://princeton.zoom.us/j/94232769862 All are welcome to join. Examiners: Jonathan Mayer (Adviser), Prateek Mittal, Aleksandra Korolova Readers: Jennifer Rexford, Seny Kamara (Brown University), and Kobbi Nissim (Georgetown University) Abstract: We illustrate how modern cryptography can offer novel solutions to longstanding policy challenges improving both privacy and accountability—–objectives that are often in tension with each other—by discussing examples from content moderation and foreign intelligence surveillance. We formalize the relevant functionalities and design practical protocols that realize them. We provide security proofs, open-source implementations, and benchmarks to demonstrate feasibility of our protocols. We describe limitations of technical answers to complex socio-technical questions. We conclude by discussing the policy impact of our contributions and promising avenues for future work.