Beaufort cipher

The Beaufort cipher, invented by some Giovanni Sestri in early 18th century but widely attributed to Sir Francis Beaufort,^[1] is a substitution cipher similar to the Vigenère cipher, with a slightly modified enciphering mechanism and tableau.^[2] Its most famous application was in a rotor-based cipher machine, the Hagelin M-209.^[3] The Beaufort cipher is based on the Beaufort square which is essentially the same as a Vigenère square but in reverse order starting with the letter "Z" in the first row,^[4] where the first row and the last column serve the same purpose.^[5]

^ "Did Beaufort Really Use the Beaufort Cipher?". cryptiana.web.fc2.com. Retrieved 2024-01-10.
^ Franksen, Ole Immanuel, Babbage and cryptography. Or, the mystery of Admiral Beaufort's cipher. Mathematics and Computers in Simulation 35 (1993) 327-367
^ Mollin, Richard A., An Introduction to Cryptography, page 100. Chapman & Hall/CRC, 2001
^ Jörg Rothe (2006). Complexity Theory and Cryptology: An Introduction to Cryptocomplexity. Springer Science & Business Media. p. 164. ISBN 9783540285205.
^ Arto Salomaa (2013). Public-Key Cryptography: Volume 23 of Monographs in Theoretical Computer Science. An EATCS Series. Springer Science & Business Media. p. 31. ISBN 9783662026274.

[1] "Did Beaufort Really Use the Beaufort Cipher?". cryptiana.web.fc2.com. Retrieved 2024-01-10.

[2] Franksen, Ole Immanuel, Babbage and cryptography. Or, the mystery of Admiral Beaufort's cipher. Mathematics and Computers in Simulation 35 (1993) 327-367

[3] Mollin, Richard A., An Introduction to Cryptography, page 100. Chapman & Hall/CRC, 2001

[4] Jörg Rothe (2006). Complexity Theory and Cryptology: An Introduction to Cryptocomplexity. Springer Science & Business Media. p. 164. ISBN 9783540285205.

[5] Arto Salomaa (2013). Public-Key Cryptography: Volume 23 of Monographs in Theoretical Computer Science. An EATCS Series. Springer Science & Business Media. p. 31. ISBN 9783662026274.

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