Linear Cryptanalysis of Non Binary Ciphers (with an application to SAFER)

In this paper we re-visit distinguishing attacks. We show how to generalize the notion of linear distinguisher to arbitrary sets. Our thesis is that our generalization is the most natural one. We compare it with the one by Granboulan et al. from FSE'06 by showing that we can get sharp estimates of the data complexity and cumulate characteristics in linear hulls. As a proof of concept, we propose a better attack on their toy cipher TOY100 than the one that was originally suggested and we propose the best known plaintext attack on SAFER K/SK so far. This provides new directions to block cipher cryptanalysis even in the binary case. On the constructive side, we introduce DEAN18, a toy cipher which encrypts blocks of 18 decimal digits and we study its security.


Published in:
SAC 2007, 184-211
Presented at:
SAC 2007, Ottawa, Canada
Year:
2007
Publisher:
Springer
Laboratories:




 Record created 2008-01-07, last modified 2018-03-17

n/a:
Download fulltext
PDF

Rate this document:

Rate this document:
1
2
3
 
(Not yet reviewed)