Breaking A Playfair Cipher Using Memetic Algorithm


The playfair cipher operates on pairs of letters. The cipher text is broken into group of blocks, each block contains two letters. Encryption and decryption cipher depends on key search, which is a square matrix that contains 5x5 letters. The matrix contains every letter expect letter j.In this paper the cryptanalyst a playfair is presented using search techniques. It is a Memetic Algorithm, another method is used to know a key through a correct Digram letters, which is used as an essential factor in the cryptanalyst cipher text. Results without memtiec algorithm and with it have been compared, to see which one has a best solution. The result clears that the memetic algorithm has a best solution more than a classical method, and faster than without used it, which has optimal solution. The length of text is 1802 letter. The key size is 25 letters as a matrix 5x5. All the algorithms were programmed using Matlab programming as M-file, and tested successfullyic