Saturday, June 28, 2014
A level X challenge in MysteryTwister by Klaus Schmeh using the double-column transposition cipher withstood a long time against cryptanalysis efforts. Nevertheless, it was solved in November 2013 by George Lasry.
The according attack against the double-column transposition cipher was just described in the journal Cryptologia and is now implemented in CrypTool 2, based on the method presented in the article "Solving the Double Transposition Challenge with a Divide And Conquer Approach", Cryptologia, Volume 38, Issue 3 by G. Lasry, N. Kopal and A. Wacker.
Three new double-column transposition cipher challenges (level III) have been published, which don't contain the weaknesses of the old challenge:
as well as a series of level II challenges for doing some exercise in that area:
CrypTool 2 (from June 25th, 2014) contains a demonstration of the algorithm how to solve the old double-column transposition from Klaus Schmeh.
You can find the according template in the Startcenter below the structure Cryptanalysis / Classical under the following name: "Dictionary attack on the Double Columnar Transposition Cipher".