CrypTool-Online (CTO) runs in a browser and provides a huge variety of encryption methods and analysis tools including many illustrated examples.
The CODEBREAKERS.EU cryptology game -- 4th edition
On June 1st, 2015 begins a "fantastic game" starting with the 1st of six tasks on the Enigma level. The material to be studied is published twice a week, but the time in which you work out the final tasks matters the most. (2015-06-01)
The release version of CrypTool 2.0 was released on 20th Aug 2014. We would be happy if many of you use it for teaching, self-study, education and awareness and give us feedback. (2014-08-25)
Article about solving the Double-Transposition Challenge in Cryptologia
A level X challenge in MysteryTwister C3 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. (2014-06-25)