A Chaotic System and Count Tracking Mechanism-based Dynamic S-Box and Secret Key Generation

In cryptography, Block ciphers use S-Boxes to perform substitution and permutation operations on a data block. S-Boxes provide non-linearity and confusion of bits to the cryptographic algorithms. In addition, secret keys are critical security aspects for encrypting and decrypting messages. The uncertainty and randomness of the secret key and S-boxes used in the algorithm determine the extent of security against any cryptanalysis attack. This paper proposes a new mechanism to dynamically generate a secret key and S-Box each time while sending and receiving the message. These dynamically generated S-Boxes and keys depend on mutually decided security parameters and message transfer history. Furthermore, a new counter-based mechanism is introduced in this paper. These enhancement techniques are applied to the serpent cipher algorithm, and a data transfer simulation is performed to validate the efficacy of the proposed method. We observe that the dynamically generated S-box follows the strict avalanche criteria. We further validate that the encrypted message shows higher sensitivity to the S-box and the secret key in enhanced serpent cipher than the original version. However, to validate our proposed method, we test and analyze the improvements in the Serpent Cipher Algorithm.