Breaking A Playfair Cipher Using Single and Multipoints Crossover Based on Heuristic Algorithms

Abstract

The process of data protection in our time is one of the most important challenges to maintain data integrity. The massive problem of breaking ciphertext is to find the key. In this work, cryptanalyze Playfair cipher is presented using a heuristic, and optimization methods search such as Memetic algorithm (MA) and Genetic algorithms (GA) to optimize fitness function. Di-gram letters are used as an essential factor in cryptanalyzing cipher. Mathematical methods are used to identify plain text. Furthermore, Single and multi-points crossover are used as parameters in the heuristic algorithm, and two points mutation as well. The results revealed that the multi-points are better than single point, which take a chance for exchanging the key to close the key encryption. In addition to, MA is better than GA, which the number of maximum correct letters in MA was 24 out of 25 letters after 100 generations, while in GA was 20 out of 24 letters after 200 generations. MATLAB application is used for programming and tested successfully. © 2021 IEEE.