Recently, we showed how to strengthen block ciphers by decorrelation techniques. In particular, we proposed two practical block ciphers, one based on the GF(2ⁿ)-arithmetics, the other based on the x mod p mod 2ⁿ primitive with a prime p=2ⁿ(1+d). We show how to achieve similar decorrelation with a prime p=2ⁿ(1-d). For this we have to change the choice of the norm in the decorrelation theory and replace the L₈ norm by the L₂ norm. We propose a new practical block cipher which is provably resistant against differential and linear cryptanalysis