CrypTool 1 is a free software illustrating the cryptographic concepts. A great number of analysis tools and algorithms are efficiently implemented. The graphical interface and the abundant online documentation allow the user, even a newbie, to be introduced to cryptography mysteries. Many classic mechanisms (like Caesar, Vigenère), as well as asymmetric cryptography (like RSA, ECC, digital signatures or Diffie-Hellman key exchange) are explained by visual animations.
It is the most wide-spread e-learning tool about encryption, cryptography and cryptanalysis worldwide.
This open-source project started in 1998. Version 1.4.30 was released in August 2010.
It is available in 5 languages (English, German, Spanish, Polish, Serbian).
Further localizations are under development (fr, ru, el).