(Public) Verifiability for Composable Protocols Without Adaptivity or Zero-Knowledge

The Universal Composability (UC) framework (FOCS ’01) is the current standard for proving security of cryptographic protocols under composition. It allows to reason about complex protocol structures in a bottom-up fashion: any building block that UC-secure can be composed arbitrarily with other construction while retaining their guarantees. Unfortunately, some properties such as verifiability outputs require excessively strong tools achieve UC. In particular, “obviously secure” constructions cannot directly shown UC-secure, and blocks does not easily carry over construction. this work, we study Non-Interactive (Public) Verifiability UC protocols, i.e. which conditions verifier ascertain party obtained specific output from protocol. may have been part execution or not, case public verifiability. We consider setting used number applications where it ok reveal input whose gets verified analyze generically achieved using “cheap” primitives. That is, avoid having rely on adaptively secure primitives heavy computational NIZKs. As Public crucial when composing ledger, our approach beneficial designing these provably composable efficiency mind.