The XL and XSL attacks on Baby Rijndael
Elizabeth Kleiman · 2005
"There are several recently proposed algorithms for solving the over defined MQ problem, two of them are XL represented by N. Courtois, A. Klimov, J. Patarin, A. Shamir in the article "Efficient Algorithms for solving Over defined System of Multivariate Polynomial Equations" and XSL represented by N. Courtois and J. Pieprzyk in "Cryptanalysis of Block Cipher with Over defined System of Equations". There is an opinion that these algorithms may be used as an attack on AES, because AES can be represented as an over defined MQ problem. In our research we constructed a new cipher called Baby Rijndael. It is a scaled-down version of Rijndael with the same algebraic structure. We apply the XL and XSL attacks on Baby Rijndael to see if it might be possible to apply them on AES."