Paper 2014/507

How to Generate and use Universal Samplers

Dennis Hofheinz and Tibor Jager and Dakshita Khurana and Amit Sahai and Brent Waters and Mark Zhandry

Abstract

The random oracle is an idealization that allows to model a hash function as an oracle that will output a uniformly random string given an input. We introduce the notion of universal sampler scheme as a method sampling securely from arbitrary distributions. We first motivate such a notion by describing several applications including generating the trusted parameters for many schemes from just a single trusted setup. We further demonstrate the versatility of universal sampler by showing how they give rise to applications such as identity-based encryption and multiparty key exchange. We give a solution in the random oracle model based on indistinguishability obfuscation. At the heart of our construction and proof is a new technique we call “delayed backdoor programming”.

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