The Concrete Security of Two-Party Computation - Simple Definitions and Tight Proofs for PSI and Related Protocols

Explore concrete security analysis of two-party secure computation through this 34-minute conference talk that introduces a simplified indistinguishability-based security definition called InI as an alternative to traditional simulation-based approaches. Learn how this new definition proves equivalent to standard definitions for invertible functionalities, including practically important applications like Private Set Intersection (PSI) and its variants. Examine the concrete security analysis of canonical OPRF-based PSI constructions with tight security proofs, and discover how different Diffie-Hellman assumptions on underlying groups affect proof tightness for the 2H-DH OPRF protocol and corresponding DH PSI implementations. Understand the development of salted-DH PSI, a new protocol that maintains the efficiency of traditional DH-PSI while achieving tighter security guarantees, providing practical improvements for secure two-party computation applications.