Secure Two-Party Computation is Practical

Secure multi-party computation has been considered by the cryptographic community for a number of years. Until recently it has been a purely theoretical area, with few implementations with which to test various ideas. This has led to a number of optimisations being proposed which are quite restricted in their application. In this paper we describe an implementation of the two-party case, using Yao’s garbled circuits, and present various algorithmic protocol improvements. These optimisations are analysed both theoretically and empirically, using experiments of various adversarial situations. Our experimental data is provided for reasonably large circuits, including one which performs an AES encryption, a problem which we discuss in the context of various possible applications

Privacy-Preserving Distributed Set Intersection *

Abstract With the growing demand of databases outsourcing and its security concerns, we investigate privacy-preserving set intersection in a distributed scenario. We propose a one-round protocol for privacy-preserving set intersection based on a combination of secret sharing scheme and homomorphic encryption. We then show that, with an extra permutation performed by each contacted server, the cardinality of set intersection can be computed efficiently. All protocols constructed in this paper are provably secure against an honest-but-curious adversary under the Decisional Diffie-Hellman assumption