Conference article

Most mono-alphabetic substitution ciphers (MASCs) can be solved with well-known techniques, like frequency analysis, or hill climbing. However, there are exceptions. It therefore makes sense to look around for additional MASC solving techniques—like the ones described in the book Cryptanalysis by Helen Fouché Gaines. These techniques—vowel detection, digram analysis, and consonant lining—have been almost forgotten since the advent of computer technology. In this paper, two of these methods (the third one is not suitable) will be applied on a famous unsolved cryptogram, the Dorabella Cryptogram, and on an unencrypted comparison text. Although this paper will not present a solution of the Dorabella Cryptogram, a number of interesting insights will be introduced. Especially, it will be shown that one of the methods applied works surpsingly well on the comparison text and that there are still ways to improve this technique. In addition, some interesting properties of the Dorabella Cryptogram will be presented, which might be helpful for further cryptanalysis.

No keywords available

Bauer, Craig. 2017. Unsolved!. Princeton University Press, Princeton, NJ. Belfield, Richard. 2006. Can You Crack The Enigma Code. Orion Publishing, London, UK.

Fouché Gaines, Helen. 1939. Cryptanalysis. Dover Publications, New York, USA.

Guy, Jacques B. M. 1991. Vowel Identification: An Old (but Good) Algorithm. Cryptologia (4), 258- 262 (1991)

Schmeh, Klaus. 2012. Nicht zu Knacken. Hanser, Munich, Germany.

Schmeh, Klaus 2017. The Top 50 unsolved encrypted messages: 31. The MLH cryptogram Klausis Krypto Kolumne, 2017-05-23

Schmeh, Klaus 2017. Who can decipher this encrypted inscription on a cigaret case? Klausis Krypto Kolumne, 2017-11-26

Schmeh, Klaus 2017. Mathematical formula needed Klausis Krypto Kolumne, 2017-12-22

Schneier, Bruce 2006. Handwritten Real-World Cryptogram Schneier on Security, 2006-01-30

Wikipedia. Dorabella Cipher. Retreived 2018-01-08. Wikipedia. Voynich manuscript. Retreived 2018-01-08.