Paper 2017/507 Original: eprint.iacr.org/2017/507 ↗

Inverted Leftover Hash Lemma

Maciej Obremski
Maciej Skórski
Abstract

Universal hashing found a lot of applications in computer science. In cryptography the most important fact about universal families is the so called Leftover Hash Lemma, proved by Impagliazzo, Levin and Luby. In the language of modern cryptography it states that almost universal families are good extractors. In this work we provide a somewhat surprising characterization in the opposite direction. Namely, every extractor with sufficiently good parameters yields a universal family on a noticeable fraction of its inputs. Our proof technique is based on tools from extremal graph theory applied to the ”collision graph” induced by the extractor, and may be of independent interest. We discuss implications for randomness extractors and non-malleable codes.

Metadata
Available format(s)
PDF
Category
Foundations
Publication info
Preprint.
History
2017-07-07: last updated
2017-06-02: published
Short URL
https://ia.cr/2017/507
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2017/507,
      author = {Maciej Obremski and Maciej Skórski},
      title = {Inverted Leftover Hash Lemma},
      howpublished = {Cryptology {ePrint} Archive, Paper 2017/507},
      year = {2017},
      url = {https://eprint.iacr.org/2017/507}
}
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