Paper 2018/984
Pseudorandomness Against Mean and Variance Bounded Attackers
Maciej Skorski
Abstract
The recent progress in key derivation (Barak at al. CRYPTO'11, Dodis Yu TCC'2013) introduced the concept of constrained profiles for attackers advantage, recognizing that security bounds can be significantly improved (alternatively: lots of randomness can be saved) when the advantage, as the function of the key, is bounded in mean or variance. This paper studies \emph{minimal requirements for keys} to achieve security under such restricted attackers. We frame the problem as characterizing \emph{pseudorandomness against constrained distinguishers} and show that minimal assumptions are respectively (a) high smooth min-entropy and (b) high smooth collision entropy. This matches the (folklore extension of) assumptions of previous works. Besides providing lower bounds, we offer more insights into this key derivation problem and elegant proof techniques of geometric flavor.
Note: This paper extends and fixes a flaw in my previous paper "Optimal Overcoming Weak Expectations" (currently withdrawn)
Metadata
- Available format(s)
-
PDF
- Category
- Foundations
- Publication info
- Preprint. MINOR revision.
- Keywords
- key derivationcryptography with weak keyspseudorandomness
- Contact author(s)
- maciej skorski @ gmail com
- History
- 2018-10-18: received
- Short URL
- https://ia.cr/2018/984
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2018/984,
author = {Maciej Skorski},
title = {Pseudorandomness Against Mean and Variance Bounded Attackers},
howpublished = {Cryptology {ePrint} Archive, Paper 2018/984},
year = {2018},
url = {https://eprint.iacr.org/2018/984}
}
