Title
Decomposing the ASASA Block Cipher Construction.
Abstract
We consider the problem of recovering the internal specification of a general SP-network consisting of three linear layers (A) interleaved with two Sbox layers (S) (denoted by ASASA for short), given only black-box access to the scheme. The decomposition of such general ASASA schemes was first considered at ASIACRYPT 2014 by Biryukov et al. which used the alleged difficulty of this problem to propose several concrete block cipher designs as candidates for white-box cryptography. In this paper, we present several attacks on general ASASA schemes that significantly outperform the analysis of Biryukov et al. As a result, we are able to break all the proposed concrete ASASA constructions with practical complexity. For example, we can decompose an ASASA structure that was supposed to provide 64-bit security in roughly 2 steps, and break the scheme that supposedly provides 128-bit security in about 2 time. Whenever possible, our findings are backed up with experimental verifications.
Year
Venue
Field
2015
IACR Cryptology ePrint Archive
Block cipher,Cryptography,Computer science,Arithmetic,Ciphertext stealing
DocType
Volume
Citations 
Journal
2015
7
PageRank 
References 
Authors
0.45
8
4
Name
Order
Citations
PageRank
Itai Dinur154137.00
Orr Dunkelman21614110.26
Thorsten Kranz3131.25
Gregor Leander4128777.03