Heuristic cryptanalysis of classical and modern ciphers

Block cipher algorithms are commonly used to secure confidential information in everyday user applications. However, it is quite common for ignorant users to use familiar dictionary words as their personal passwords. This research examines the effects of weakly chosen password-keys on the security of block ciphers. A new hybrid optimization heuristic cryptanalytic attack (tabu search and genetic algorithm) is used to conduct an intelligent key-search attack on classical ciphers and modern ciphers. The algorithm chosen to represent modern block ciphers is the advanced encryption standard (AES) algorithm. AES is an algebraic product cipher which combines elements of substitution and transposition. Therefore, the primarily aims of this paper is to study the effects of an optimization heuristic cryptanalytic attack on block cipher.