CrypTool is demonstration and reference program for cryptography by Bernhard Esslinger. It is a freeware program which enables user to apply and analyze cryptographic mechanisms. It has the typical look-and-feel of a modern Windows application. CrypTool has implemented almost all state-of-the-art crypto functions and allows you to learn about and use, cryptography within the same environment.
The methods available include both classic methods and modern cryptosystems:
- classic methods: e.g. the Caesar cipher and the double-column transposition (permutation) encryption algorithm.
- modern methods: e.g. the RSA and AES algorithms, hybrid encryption and algorithms based on elliptic curves.
The source code of the CrypTool product is distributed under the terms of GPL (GNU General Public License).
I can recommend this tool for purposes of education and trainings for novices, but also for others that are already familiar with cryptography.
Visit CrypTool web site here.