A Word-Based Genetic Algorithm for Cryptanalysis of Short Cryptograms

May 2003

Proceedings of the Sixteenth International Florida Artificial Intelligence Research Society Conference (FLAIRS 2003)

Volume

Proceedings of the Sixteenth International Florida Artificial Intelligence Research Society Conference (FLAIRS 2003)

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This paper demonstrates the feasibility of a word-based genetic algorithm (GA) for solving short substitution cryptograms such as the kind found in newspapers and puzzle books. Although GA’s based on analysis of letter, digram, or trigram frequencies have been used on substitution cryptograms, they are not able to solve short (10-30 word) cryptograms of the sort we address. By using a relatively small dictionary of frequent words to initialize a set of substitution keys, and by employing a word-based crossing mechanism, the GA achieves performance that is comparable to deterministic word-based algorithms.