What is CrypTool 1?

CrypTool 1 (CT1) is an open-source Windows program for cryptography and cryptanalysis. It’s the most widespread e-learning software of its kind.

What is CrypTool 2?

CrypTool 2 (CT2) is an open-source program offering an innovative visual programming GUI to experiment with cryptographic procedures and to animate their workflow.

What is JCrypTool?

JCrypTool (JCT) is an open-source e-learning platform, allowing to experiment comprehensively with cryptography on Linux, macOS, and Windows.

What is CrypTool-Online?

CrypTool-Online (CTO) runs in a browser and provides a variety of encryption and cryptanalysis methods including illustrated examples and tools like password generator and password meter.

What is MysteryTwister C3?

MysteryTwister C3 (MTC3) is an international Crypto Cipher Contest offering a broad variety of challenges, a moderated forum, and an ongoing hall-of-fame.


Codes are used to transform data into a format, which is more convenient for the target application. One of the most common codes is the bar code, which can be optically scanned. Bar codes are found on nearly every packaging. Subsequently, supermarkets, for example, are able to rapidly capture the data on the bar codes at the check out counter. The more modern QR code can be recognized and decoded by every smartphone.

Bar codes and QR codes are used a lot, but the usage of the ASCII code exceeds the use of bar codes by far, even if we are not aware of this fact. Every keystroke on a keyboard is transformed into a bit string the computer is able to interpret.

On this website and the other recommended website, you have the opportunity to experiment with commonly used coding methods.