Cryptanalysis of 1-Round KECCAK.

In this paper, we give the first pre-image attack against 1-round KECCAK-512 hash function, which works for all variants of 1-round KECCAK. The attack gives a preimage of length less than 1024 bits by solving a system of 384 linear equations. We also give a collision attack against 1-round KECCAK using similar analysis.