SHARK
In cryptography, SHARK is a block cipher identified as one of the predecessors of Rijndael.
SHARK has a 64-bit block size and a 128-bit key size. It is a six round SP-network which alternates a key mixing stage with linear and non-linear transformation layers. The linear transformation uses an MDS matrix representing a Reed-Solomon error correcting code in order to guarantee good diffusion. The nonlinear layer is composed of eight 8×8-bit S-boxes based on the function F = x−1 over GF.
Five rounds of a modified version of SHARK can be broken using an interpolation attack.
