International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Valérie Nachef

Affiliation: University of Cergy-Pontoise

Publications

Year
Venue
Title
2014
EPRINT
2010
ASIACRYPT
2007
ASIACRYPT
2007
EPRINT
Generic Attacks on Unbalanced Feistel Schemes with Expanding Functions
Valérie Nachef Jacques Patarin C?me Berbain
\begin{abstract} Unbalanced Feistel schemes with expanding functions are used to construct pseudo-random permutations from $kn$ bits to $kn$ bits by using random functions from $n$ bits to $(k-1)n$ bits. At each round, all the bits except $n$ bits are changed by using a function that depends only on these $n$ bits. C.S.Jutla \cite{Jut} investigated such schemes, which he denotes by $F^d_k$, where $d$ is the number of rounds. In this paper, we describe novel Known Plaintext Attacks (KPA) and Non Adaptive Chosen Plaintext Attacks (CPA-1) against these schemes. With these attacks we will often be able to improve the result of C.S.Jutla. We also give precise formulas for the complexity of our attacks in $d$, $k$ and $n$. \end{abstract}
2006
ASIACRYPT