On the Differential Cryptanalysis of SEPAR Cipher

SEPAR is a lightweight cryptographic algorithm, designed to implement on resource-constrained devices especially those employed in IoT environments. Meanwhile, the mixed structure design of cipher leads to speed improvement while guaranteeing its resistance against common cryptographic attacks, especially differential and linear attacks. In order to confirm the resistance of the cipher against differential attack, an extensive investigation was presented in our previous work. In his study, we conduct new research continuing the previously presented research. We prove that there are enough active S-boxes so as to resist cipher against differential cryptanalysis. Moreover, this can provide a tight bound of resisting cipher against this attack.