MysteryTwister (MTC3) is an international cryptography competition. Its origin is a design study called A Crypto Challenge by CrypTool (C3) and the replacement of the renowned Mystery Twister site of Professor Dobbertin (RUB).
MTC3 offers a variety of challenges (tasks and riddles) in four levels: These challenges can be as easy as deciphering a Caesar cipher (level I) and as hard as breaking a modern encryption algorithm such as AES (level III). Level X challenges are kind of "mysterious".
The various topics covered by the MTC3 challenges should appeal to almost anyone with an interest in cryptology: For students just starting to learn about it as well as for experts with many years of experience and plenty of resources at their disposal.
For challenges of level I to III the website automatically verifies if your solution is correct. The solution may be the entire plaintext, the key, or a secret codeword hidden in the plaintext.
To submit your solutions, you first have to register. Be aware that the solutions are case-sensitive! If your answer is correct, you will automatically be awarded with the according points and added to the list of successful code breakers: Every successful candidate will appear in the Global Hall of Fame. The first three successful code breakers of each challenge will be immortalized in the Challenges Hall of Fame separately for each challenge.
However, you have only a limited number of attempts for each challenge. Therefore, you should be sure that your answer is correct before submitting a solution. Once you have used all of your attempts, you will not be able to submit additional answers for that particular challenge.
Challenges categorized as level X are not validated automatically. If you solve one of the level X challenges, you should contact the MysteryTwister team via email. Your solution will be checked by the author or another expert. We will publish your results only with your explicit permission.
For every challenge there is a forum. There you can ask questions and submit hints– but please do not provide the solution.
Additionally, authors sometimes add hints if too many users get set on the wrong track.
As we open a forum thread for each new challenge, please ask challenge-related questions only in this existing thread.
In order to continuously enhance MTC3 with new challenges, we need your help. If you have an idea for an interesting challenge, don't hesistate to submit your suggestion.
To do so, you have to register (if you are already registered in order to solve challenges, this is sufficient). We then will check the suggestion and will publish it as an MTC3 challenge.
Detailed information on how you can submit your own challenge can be found here.