Title
Algebraic Attacks and Decomposition of Boolean Functions
Abstract
Algebraic attacks on LFSR-based stream ciphers recover the secret key by solving an overdefined system of multivariate algebraic equations. They exploit multivariate relations involving key bits and output bits and become very efficient if such relations of low degrees may be found. Low degree relations have been shown to Exist for several well known constructions of stream ciphers immune to all previously known attacks. Such relations may be derived by multiplying the output function of a stream cipher by a well chosen low degree function such that the product function is again of low degree. In view of algebraic attacks, low degree multiples of Boolean functions are a basic concern in the design of stream ciphers as well as of block ciphers. This paper investigates the existence of low degree multiples of Boolean functions in several directions: The known scenarios under which low degree multiples exist are reduced and simplified to two scenarios, that are treated differently in algebraic attacks. A new algorithm is proposed that allows to successfully decide whether a Boolean function has low degree multiples. This represents a significant step towards provable security against algebraic attacks. Furthermore, it is shown that a recently introduced class of degree optimized Maiorana-McFarland functions immanently has low degree multiples. Finally, the probability that a random Boolean function has a low degree multiple is estimated.
Year
DOI
Venue
2004
10.1007/978-3-540-24676-3_28
ADVANCES IN CRYPTOLOGY - EUROCRYPT 2004, PROCEEDINGS
Keywords
Field
DocType
algebraic attacks,stream ciphers,boolean functions,algebraic degree,annihilator,low degree multiple,resiliency
Boolean function,Discrete mathematics,Algebraic number,Block cipher,Cryptography,Computer science,Symmetric Boolean function,Algebraic equation,Stream cipher,Correlation attack
Conference
Volume
ISSN
Citations 
3027
0302-9743
166
PageRank 
References 
Authors
7.16
13
3
Search Limit
100166
Name
Order
Citations
PageRank
Willi Meier167534.67
Enes Pasalic236242.34
Claude Carlet32925226.81