Secure Two-Party Computation with Low Communication

Abstract

We propose a 2-party UC-secure protocol that can compute any function securely. The protocol requires only two messages, communication that is poly-logarithmic in the size of the circuit description of the function, and the workload for one of the parties is also only poly-logarithmic in the size of the circuit. This implies, for instance, delegatable computation that requires no expensive off-line phase and remains secure even if the server learns whether the client accepts its results. To achieve this, we define two new notions of extractable hash functions, propose an instantiation based on the knowledge of exponent in an RSA group, and build succinct zero-knowledge arguments in the CRS model