Everlasting UC Commitments from Fully Malicious PUFs

Abstract Everlasting security models the setting where hardness assumptions hold during execution of a protocol but may get broken in future. Due to strength this adversarial model, achieving any meaningful guarantees for composable protocols is impossible without relying on hardware (Müller-Quade and Unruh, JoC’10). For reason, rich line research has tried leverage physical construct well-known everlasting cryptographic primitives, such as commitment schemes. The only known everlastingly UC secure scheme, due Müller-Quade Unruh (JoC’10), assumes honestly generated tokens. authors leave possibility constructing commitments from malicious tokens an open problem. Goyal et al. (Crypto’10) constructs unconditionally UC-secure computation tokens, with caveat that honest must encapsulate other This extra restriction rules out interesting classes physically uncloneable functions (PUFs). In work, we present first construction scheme fully token model requiring encapsulation. Our existence PUFs common reference string model. We also show our results are tight by giving impossibility proof non-erasable (such PUFs), even trusted setup.