Algebraic Cryptanalysis of Reduced AES

Algebraic attack on AES was proposed, recently. It was called XSL attack. The suggested computational complexity of this attack on AES is in theory polynomial in the number of rounds. So the computational complexity of the attack does not reduce significantly by decreasing the number of rounds. Therefore the implementation of attack is not practical even for the low number of AES round. In addition, the estimate given for the number of linearly independent equations generated by XSL technique is not proved exactly and it can not be checked even for reduced AES, because the mentioned reason. But there is a question: weather it may be possible to have another equation system expressing the AES that enable the algebraic attack on reduced AES with computational complexity lower than exhaustive search attack. In this paper a new equation system for AES is proposed that results in new algebraic attack on reduced AES up to 5 rounds. Solving this equation system even by worst method like guessing the unknowns is faster than the brute force attack.

Algebraic Cryptanalysis of Reduced AES Keywords:

AES , Algebraic Attack , Ground Idea