International Association for Cryptologic Research

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Paper: The Price of Verifiability: Lower Bounds for Verifiable Random Functions

Authors:
Nicholas Brandt , ETH Zurich
Dennis Hofheinz , ETH Zurich
Julia Kastner , ETH Zurich
Akin √únal , ETH Zurich
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Presentation: Slides
Conference: TCC 2022
Abstract: Verifiable random functions (VRFs) are a useful extension of pseudorandom functions for which it is possible to generate a proof that a certain image is indeed the correct function value (relative to a public verification key). Due to their strong soundness requirements on such proofs, VRFs are notoriously hard to construct, and existing constructions suffer either from complex proofs (for function images), or rely on complex and non-standard assumptions. In this work, we attempt to explain this phenomenon. We show that for a large class of pairing-based VRFs, it is not possible to obtain short proofs and a reduction to a simple assumption simultaneously. Since the class of "consecutively verifiable" VRFs we consider contains in particular the VRF of Lysyanskaya and that of Dodis-Yampolskiy, our results explain the large proof size, resp. the complex assumption of these VRFs.
BibTeX
@inproceedings{tcc-2022-32467,
  title={The Price of Verifiability: Lower Bounds for Verifiable Random Functions},
  publisher={Springer-Verlag},
  author={Nicholas Brandt and Dennis Hofheinz and Julia Kastner and Akin √únal},
  year=2022
}