Publicly evaluable pseudorandom functions and their applications

Abstract

We put forth the notion of publicly evaluable pseudorandom functions (PEPRFs), which is a non-trivial extension of the standard pseudorandom functions (PRFs). Briefly, PEPRFs are defined over domain X containing an NP language L in which the witness is hard to extract on average, and each secret key sk is associated with a public key pk. For any x ∈ L, in addition to evaluate F sk (x) using sk as in the standard PRFs, one is also able to evaluate F sk (x) with pk, x and a witness w for x ∈ L. We conduct a formal study of PEPRFs, focusing on applications, constructions, and extensions. In more details: