An Analysis of the XSL Algorithm
- 1.9k Downloads
The XSL “algorithm” is a method for solving systems of multivariate polynomial equations based on the linearization method. It was proposed in 2002 as a dedicated method for exploiting the structure of some types of block ciphers, for example the AES and Serpent. Since its proposal, the potential for algebraic attacks against the AES has been the source of much speculation. Although it has attracted a lot of attention from the cryptographic community, currently very little is known about the effectiveness of the XSL algorithm. In this paper we present an analysis of the XSL algorithm, by giving a more concise description of the method and studying it from a more systematic point of view. We present strong evidence that, in its current form, the XSL algorithm does not provide an efficient method for solving the AES system of equations.
KeywordsXSL algorithm T′ method Linearization AES
- 6.Coppersmith, D.: Comments on Crypto-Gram Newsletter (October 2002), http://www.schneier.com/crypto-gram-0210.html
- 10.Courtois, N., Pieprzyk, J.: Cryptanalysis of Block Ciphers with Overdefined Systems of Equations. Cryptology ePrint Archive, Report 2002/044 (2002)Google Scholar
- 15.Sugita, M., Kawazoe, M., Imai, H.: Relation between XL algorithm and Gröbner Bases Algorithms. Cryptology ePrint Archive, Report 2004/112 (2004)Google Scholar