4. Universally Composable Multi-party Computation

Abstract

In this chapter we prove a fundamental result stating that secure multiparty computation that remains secure under concurrent general composition can be achieved, for any number of corrupted parties. That is, we consider an asynchronous multi-party network and an adversary that can adaptively corrupt as many parties as it wishes. We present protocols that allow any subset of parties in this setting to securely realize any desired functionality of their inputs, and be guaranteed that security is preserved regardless of the activity in the rest of the network. Our protocols are in the common reference string model and rely on standard intractability assumptions.