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1	Optimisation Heuristics for Cryptology Clark, Andrew J. January 1998 (has links) The aim of the research presented in this thesis is to investigate the use of various optimisation heuristics in the fields of automated cryptanalysis and automated cryptographic function generation. These techniques were found to provide a successful method of automated cryptanalysis of a variety of the classical ciphers. Also, they were found to enhance existing fast correlation attacks on certain stream ciphers. A previously proposed attack of the knapsack cipher is shown to be flawed due to the absence of a suitable solution evaluation mechanism. Finally, a new approach for finding highly nonlinear Boolean functions is introduced. Automated cryptanalysis cryptography cryptology simulated annealing genetic algorithm tabu search polyalphabetic substitution cipher transposition cipher stream cipher nonlinear combiner Merkle-Hellman knapsack Boolean function nonlinearity.