CryptoDB
On the Complexity of Collision Resistant Hash Functions: New and Old Black-Box Separations
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| Abstract: | The complexity of collision-resistant hash functions has been long studied in the theory of cryptography. While we often think about them as a Minicrypt primitive, black-box separations demonstrate that constructions from one-way functions are unlikely. Indeed, theoretical constructions of collision-resistant hash functions are based on rather structured assumptions.We make two contributions to this study: 1.A New Separation: We show that collision-resistant hashing does not imply hard problems in the class Statistical Zero Knowledge in a black-box way.2.New Proofs: We show new proofs for the results of Simon, ruling out black-box reductions of collision-resistant hashing to one-way permutations, and of Asharov and Segev, ruling out black-box reductions to indistinguishability obfuscation. The new proofs are quite different from the previous ones and are based on simple coupling arguments. |
BibTeX
@article{tcc-2019-29981,
title={On the Complexity of Collision Resistant Hash Functions: New and Old Black-Box Separations},
booktitle={Theory of Cryptography},
series={Lecture Notes in Computer Science},
publisher={Springer},
volume={11891},
pages={422-450},
doi={10.1007/978-3-030-36030-6_17},
author={Nir Bitansky and Akshay Degwekar},
year=2019
}