Cryptanalysis of Homophonic Substitution Ciphers Using Simulated Annealing with Fixed Temperature

Nils Kopal
University of Siegen, Germany

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Ingår i: Proceedings of the 2nd International Conference on Historical Cryptology, HistoCrypt 2019, June 23-26, 2019, Mons, Belgium

Linköping Electronic Conference Proceedings 158:12, s. 107-116

NEALT Proceedings Series 37:12, s. 107-116

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Publicerad: 2019-06-12

ISBN: 978-91-7685-087-9

ISSN: 1650-3686 (tryckt), 1650-3740 (online)


This paper describes the current progress of our research in the area of breaking homophonic substitution ciphers. Furthermore, it presents the state-of-the-art of cryptanalyzing this kind of cipher. There is a huge gap between the success rate of methods published in according research papers and the success rate of already available tools on the Internet. This paper also presents a small general taxonomy of monoalphabetic substitution ciphers. Finally, it shows how we broke different homophonic substitution ciphers in an automatic as well as in a semi-automatic way.


automatic cryptanalysis semi-automatic cryptanalysis homophonic substitution ciphers hillclimbing simulated annealing fixed temperature DECRYPT project CrypTool 2


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