Secure Multiparty Computation with Lazy Sharing

Secure multiparty computation (MPC) protocols enable n parties, each with private inputs, to compute a given function without leaking information beyond the outputs. One of the main approaches to designing efficient MPC protocols is to use secret sharing. In general, secret sharing based MPC contains three phases: input sharing, circuit evaluation, and output recovery. If the adversary corrupts at most t parties, the protocol typically uses (t,n) threshold secret sharing to share the inputs. In this work, we consider a weaker variant of threshold secret sharing called lazy threshold secret sharing (or simply lazy sharing) and show that: Lazy sharing can serve as a viable alternative to threshold secret sharing in MPC without compromising security. Lazy sharing could be generated more efficiently than threshold secret sharing.