"CrypTool includes an unparalleled array of cryptologic tools, which are ideal for anyone who wants to study cryptography or cryptanalysis. CrypTool is a free application, readily available on the Internet."

"Cryptography is the core technology of IT security solutions and in therefore of great practical importance and there is a need to raise awareness for crypto techniques. But cryptography is very mathematical and therefore hard to understand and to use for most people. CrypTool closes this gap. The system makes cryptography accessible for a great audience."

"In Warsaw University of Technology we have been using CrypTool for five years. It is especially useful for students who need soft, but comprehensive introduction into IT security. As far, as I know there are no other applications in this field with so many didactic features."

"Thanks a lot for the release of CrypTool, which is an excellent tool for teaching cryptography. As for the feedback from the students, I would like to mention that I haven't had any complaints about CT. Generally, students are very positive about the tool and we are certainly continue to use it in our lab."

"I'm an information security teacher here in Sao Paulo, Brazil and wanna say thanks to your team! Your tool is amazing and let the students know more and see the complex, but wonderful world of cryptography :)"

"We would like to thank the CrypTool team for having put together the CrypTool-Online website, especially for the password checker and password generator. With permission from your team we integrated these functions into our internal corporate security web site. This helps our users to better understand in detail what kind of passwords are good and qualify for usage. We'd like to mention that it was easy to customize the scripts to reflect our internal password policy, which helped us to adopt the tool to real life. We hope this encourages your students to continue their path of providing useful tools and solutions."

"I am a big fan of CrypTool and use it within PwC Belgium and beyond for educating our consultants in cryptographic basics."

"Thanks for giving us CrypTool."

"The non-numerate students found the pictorial descriptions of how the various processes work invaluable. They speak of CrypTool helping to remove their fear of the subject. A few have even reluctantly admitted that CrypTool brought the subject to life and made it fun."

"CrypTool has been produced in an extremely professional and innovative way. It is helpful as an educational tool for the novice and provides excellent practical experience for the knowledgeable."

"CrypTool meets very important requirements. It gives educators - and those who want to educate themselves - an opportunity to experiment with cryptography based on sound implementations of state-of-the-art algorithms."

"CrypTool already provides a strong basis for educational activities and there is great merit in continuing this development. There is scope for adding new algorithms, [...], and new cryptanalytic methods as they emerge. In summary I feel that CrypTool can play a very fruitful role in education about cryptography, and thus have a positive impact on this field in general."

"On the one hand, CrypTool has very efficient implementations including cryptanalysis and all relevant standards. So the tool is technically very useful. On the other hand, the visualization and presentation of the cryptographic techniques in CrypTool is excellent and there is no system that I know of that combines those two qualities in such an outstanding way."

"We at the Institute of Information Management at the University of St. Gallen use CrypTool in our lecture."

"I have been using CrypTool as a software tool to demonstrate the working principles of cryptographic algorithms and protocols, and to complement m lectures on computer and network security accordingly. My experience is that students like to work with CrypTool and to discover the wide range of cryptographic algorithms and protocols it implements. The tool provides an excellent playground to do lab studies and exercises."

"In the field of educating students or IT-professionals, this tool gives you much support and wonderful help to increase their knowledge. Beside of theoretical background, it gives the possibility to consolidate the knowledge by practical experiences. Only this mixture of theory and practice leads to real understanding."

"This tool teaches in a very easy and touchy way, how to implement confidentiality, integrity and evidence (electronic signatures). Especially the understanding of electronic signatures will be of a very high importance for the time to come. Customers must understand this technology, otherwise there will be no trust or confidence in e-Government or e-Commerce, and the huge investments in these areas will generate no return."

"Especially the didactical brilliant tutorials and the use of new media help lecturers, teachers, security managers and employees within companies and of cause also citizens to make cryptography understandable."

"CrypTool educates PC users about the basics of cryptography in a fascinating way. It allows the exploration of various crypto mechanisms in a very illustrative way. The implementation of ancient algorithms provides an interesting walk through the history of cryptology - ending up with a comprehensive demonstration of all modern implementations."

"Installing CrypTool only requires a few clicks of the mouse, and learning how to use the application is equally straightforward. There is also an extensive amount of help available in each tutorial. In addition, new crypto algorithms and attacks are constantly being added to the (already impressive) CrypTool suite, making it ever more comprehensive in its scope."

"In the last few years, CrypTool has become to an indispensable part of my lectures in IT security. Due to its broad concept, the clear structure, and the explicatory and illustrative character, the software is suitable both for the lecturer's presentations and the student's self learning. CrypTool is very stable and consistent."

"I've been using CrypTool for years in internships for IT-Security at the University of Klagenfurt and Distance Learning Computer Science at the University of Applied Science Trier. CrypTool is used here among the students with enthusiasm because in many cases it awakes the play instincts in the up-and-coming computer scientists (e.g. through manual decryption of ciphertexts or number games.) If only learning were always such fun, then it would be much easier for us students!"

"In addition to the appealing appearance and the extensive scope of operation, the team of CrypTool developers must also be praised. Wishes regarding missing functionality or suggestions for improvement are always promptly acted on and, where possible, integrated into new versions. In addition, the path chosen for recent developments is in my opinion a great success: Especially the building-block design with the independent modules (e.g: encryption, hashes or signature) that can be combined in activities, will be an inspiration for students."

"CrypTool can be highly recommended for experimenting with the individual algorithms."

"I really like CrypTool. Despite the extensive possibilities, it is not too complex for the user, with further simplification due to the synergies between the menus and the extensive documentation. Thanks to the defaults, it is possible to quickly get started with trying out individual modules, even if one might not fully understand the exercises in the beginning. But this piques the interest to dig deeper into the possibilities."

"For practical applications, we find ourselves reaching more and more for CrypTool because the students are presented with a comprehensive offering of practical implementations of algorithms."

"The high level of functionality, as well as the interactive and user-friendly interface make this educational software an ideal supplement to our own curriculum."

"The freely-available demonstration program CrypTool is highly recommended for practical exercises."

"CrypTool is unique. It provides an entertaining and exciting way of learning."

"I have been using CrypTool to support laboratory teaching of our cryptography class at Royal Holloway, University of London for several years now and it just keeps getting better and better. (September 2012) , Director of the Information Security Group (ISG) at Royal Holloway, University of London."

"CrypTool 2 is a great app. All of my students use it every semester. Students have really enjoyed doing the projects that use CrypTool. They really like seeing how encryption works. CrypTool makes learning cryptography fun. I highly recommend it to undergraduate and graduate students. I wish there were more room in my books to write more about CrypTool."

"The crypto tools you made available are really great for learning how algorithms work. CrypTool has been used for understanding better the various options offered by existing security algorithms. Security of data is a point of upmost importance in mobile telecommunication and particularly in the sim card environment."

"The CT2 program is an excellent tool for conducting cryptology exercises that does not require any prior knowledge of programming languages, which until now was necessary to implement its algorithms. This is especially important at the international university Vistula in Warsaw, which brings together students from about 100 countries with different levels of programming knowledge. I save time by transferring them to structural thinking, which goes directly to the essence of cryptology and its methods. If we recall that about 80% of human perception is provided by his sight, CT2 makes full use of it."

"I am a teacher of Cryptology courses and CrypTool software becomes one of the strongest elements of my tutorials."

"About CrypTool: Thanks a lot for your excellent work that benefits so many students, instructors, and crypto-hobbyists all over the world!"