Paper 2014/151
Security Analysis of Key-Alternating Feistel Ciphers
Rodolphe Lampe and Yannick Seurin
Abstract
We study the security of \emph{key-alternating Feistel} ciphers, a class of key-alternating ciphers with a Feistel structure. Alternatively, this may be viewed as the study of Feistel ciphers where the pseudorandom round functions are of the form $F_i(x\oplus k_i)$, where $k_i$ is the (secret) round key and $F_i$ is a \emph{public} random function that the adversary is allowed to query in a black-box way. Interestingly, our results can be seen as a generalization of traditional results \emph{à la} Luby-Rackoff in the sense that we can derive results for this model by simply letting the number of queries of the adversary to the public random functions $F_i$ be zero in our general bounds. We make an extensive use of the coupling technique. In particular (and as a result of independent interest), we improve the analysis of the coupling probability for balanced Feistel schemes previously carried out by Hoang and Rogaway (CRYPTO 2010).
Note: An abridged version appears in the proceedings of FSE 2014. This is the full version.
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- A minor revision of an IACR publication in FSE 2014
- Keywords
- block cipherkey-alternating cipherFeistel ciphercouplingprovable security
- Contact author(s)
-
rodolphe lampe @ gmail com
yannick seurin @ m4x org - History
- 2014-03-01: received
- Short URL
- https://ia.cr/2014/151
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2014/151,
author = {Rodolphe Lampe and Yannick Seurin},
title = {Security Analysis of Key-Alternating Feistel Ciphers},
howpublished = {Cryptology {ePrint} Archive, Paper 2014/151},
year = {2014},
url = {https://eprint.iacr.org/2014/151}
}
