DEAL is a DES-based block cipher proposed by Knudsen. The block size of DEAL is 128 bits, twice as much as the DES block size. The main result of the current paper is a certificational attack on DEAL192, the DEAL variant with a 192-bit key. The attack allows a trade-off between the number of plaintext/ciphertext pairs and the time for the attacker’s computations. Nevertheless, the DEAL design p...