International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Valérie Nachef

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