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.

About CrypTool-Online (CTO)

Encrypt directly within your browser

CrypTool-Online provides an exciting insight into the world of cryptology. A variety of ciphers, coding methods, and analysis tools are introduced together with illustrated examples. Our emphasis is on making explanations easy to understand in order to further the general interest in cryptography and cryptanalysis. Therefore, you can experiment with the introduced methods in an interactive way directly on the website.

So you can learn the fundamentals of historically relevant ciphers in a little while , and also use the tools under Ciphers to encrypt messages yourself. You can also decrypt and analyze already encrypted messages and discover weaknesses of different ciphers. Under Highlights, you can for instance check the modern cipher AES or let the site generate good passwords for you.

CrypTool-Online is the online version of the e-learning program CrypTool. The so-called download (or offline) versions of CrypTool are also free and suitable for working with longer texts and conducting high performance analyses on encrypted messages.

Developers who like to join and enhance CTO with self-written plugins, find a good guidance in the Wiki. Especially the page How-to-Start leads you step-by-step.

This site works together with the website www.cryptoprograms.com, and partly is a successor of it. The author of cryptoprograms.com also develops the famous Windows analyzer of classic ciphers CryptoCrack.