International Association for Cryptologic Research

International Association
for Cryptologic Research

IACR News item: 21 June 2015

Krzysztof Pietrzak, Maciej Skorski
ePrint Report ePrint Report
Computationalnotionsofentropy(a.k.a.pseudoentropy)have found many applications, including leakage-resilient cryptography, deter- ministic encryption or memory delegation. The most important tools to argue about pseudoentropy are chain rules, which quantify by how much (in terms of quantity and quality) the pseudoentropy of a given random variable X decreases when conditioned on some other variable Z (think for example of X as a secret key and Z as information leaked by a side-channel). In this paper we give a very simple and modular proof of the chain rule for HILL pseudoentropy, improving best known parameters. Our version allows for increasing the acceptable length of leakage in ap- plications up to a constant factor compared to the best previous bounds. As a contribution of independent interest, we provide a comprehensive study of all known versions of the chain rule, comparing their worst-case strength and limitations.

Expand

Additional news items may be found on the IACR news page.