Cryptanalysis of the LAKE Hash Family

We analyse the security of the cryptographic hash function LAKE-256 proposed at FSE 2008 by Aumasson, Meier and Phan. By exploiting non-injectivity of some of the building primitives of LAKE, we show three different collision and near-collision attacks on the compression function. The first attack uses differences in the chaining values and the block counter and finds collisions with complexity 2^{33}. The second attack utilizes differences in the chaining values and salt and yields collisions with complexity 2^{42}. The final attack uses differences only in the chaining values to yield near-collisions with complexity 2^{99}. All our attacks are independent of the number of rounds in the compression function. We illustrate the first two attacks by showing examples of collisions and near-collisions.