Swarm Intelligence and Evolutionary Computation based Cryptography and Cryptanalysis of 4-round DES algorithm

Over the past decade, there has been an increasing research in the application of Fuzzy Logic and Evolutionary Computation methods to problems in the field of cryptography and cryptanalysis. This is primarily due to the effectiveness of application of these methods to handle hard problems, and to the resulting automated designs pertaining to cryptanalysis of cryptosystems. This paper begins with a brief introduction to cryptography and fuzzy-evolutionary computation methods. A short survey of the applications of these computational intelligence techniques to cryptographic problems follows, and then our contribution is presented. Specifically, we have viewed some cryptographic problems as discrete/continuous optimization problems and are addressed using Evolutionary Computation methods, particularly swarm intelligence and particle swarm optimization. Furthermore, the effectiveness of Swarm Intelligence to optimize the search space of some of the cryptographic functions is studied. Finally, theoretical issues of image cryptography are presented. The experimental results suggest that the discrete optimization problem formulation and representation are critical factors that determine the performance of Evolutionary Computation methods to cryptography. Moreover, strong cryptosystems must not reveal the inherent patterns of the encrypted messages, their decryption keys and the encryption algorithm structure, it is reported that swarm intelligence and evolutionary computation methods constitute a strong measure of the cryptosystems’ security. Keywords— Cryptography, cryptanalysis, cryptosystem, evolutionary computation, computational intelligence, encryption, decryption, swarm intelligence.