Cryptanalysis of Strumok Cipher Initialization

The initialization of the Strumok cipher is analyzed in this paper. A modified cipher initialization procedure is constructed for the Strumok-512 cipher, which allows to show that the cipher initialization is not injective. Security against slide attacks is proved. Furthermore, the Guess-and-Determine attack on the Strumok-512 cipher is constructed with complexity 2⁴⁴⁸.