Schmeh's cryptogram finally solved after 6 years!

Heureka, the cryptogram that was published in 2007 by Klaus Schmeh [1] was finally solved on 26.11.2013 by George Lasry. MysterieTwister (user: george4096) made today the official announcement about his achievement.



Over 6 years Schmeh's cryptogram resisted all attacks despite it is based on a cipher that can be executed with pencil and paper. Because of its difficulty it was brought to public attention in various forms, e.g. [2,3]. Schmeh did not chose the puzzle in an arbitrary way. No, it was particularly well chosen according to the rules from the former BSI president Otto Leiberich. Based on the cryptanalysis knowledge at that time, the parameters were picked in a way to make the cryptogram as hard as possible. This means for example to take $2$ keys of length $> 20$ that create incomplete rectangles during encryption.

In the post Double Columnar Transposition i talked about various methods to attack this type of cipher and also made some statements about the cryptopuzzle from Schmeh. Then George Lasry made comments to my blog post and we exchanged several e-mails talking about his approach and ideas to increase efficiency. He told me, that he worked since a few month on that puzzle after having extensively studied the single transposition and the ADFGX cipher before. I guess that brought him in the right position to be ready for Schmeh's cryptogram.

Congratulations to him! 

Details of his approach will follow as soon as his official paper is accepted.

[1] Klaus Schmeh, Codeknacker gegen Codemacher: Die faszinierende Geschichte der Verschlüsselung, 414 Seiten, 2007
[2] http://www.heise.de/tp/artikel/26/26876/1.html
[3] Klaus Schmeh, Nicht zu knacken, 296 Seiten, 2012, Carl Hanser Verlag GmbH & Co. KG