CryptoDB
Constructing Verifiable Random Functions with Large Input Spaces
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Abstract: | We present a family of verifiable random functions which are provably secure for exponentially-large input spaces under a non-interactive complexity assumption. Prior constructions required either an interactive complexity assumption or one that could tolerate a factor 2^n security loss for n-bit inputs. Our construction is practical and inspired by the pseudorandom functions of Naor and Reingold and the verifiable random functions of Lysyanskaya. Set in a bilinear group, where the Decisional Diffie-Hellman problem is easy to solve, we require the Decisional Diffie-Hellman Exponent assumption in the standard model, without a common reference string. Our core idea is to apply a simulation technique where the large space of VRF inputs is collapsed into a small (polynomial-size) input in the view of the reduction algorithm. This view, however, is information-theoretically hidden from the attacker. Since the input space is exponentially large, we can first apply a collision-resistant hash function to handle arbitrarily-large inputs. |
BibTeX
@misc{eprint-2010-23003, title={Constructing Verifiable Random Functions with Large Input Spaces}, booktitle={IACR Eprint archive}, keywords={foundations / VRF, PRF, large inputs, standard model}, url={http://eprint.iacr.org/2010/102}, note={To appear in Eurocrypt 2010. This is the full version. susan@cs.jhu.edu 14753 received 24 Feb 2010, last revised 23 May 2010}, author={Susan Hohenberger and Brent Waters}, year=2010 }