Vinod Vaikuntanathan (
Hoeteck Wee (
We construct functional encryption schemes for polynomial-time computable functions secure against an a-priori bounded polynomial number of collusions, assuming the existence of semantically secure public-key encryption schemes. During the course of our constructions, we show a “bootstrapping theorem” that constructs a $q$-query functional encryption scheme for arbitrary functions starting from a $q$-query functional encryption scheme for bounded-degree functions. All our constructions rely heavily on techniques from secure multi-party computation and randomized encodings.
Our constructions are secure under a strong simulation-based definition of functional encryption.