We redesigned MysteryTwister, enjoy! Feedback

Explore Challenges

93 challenges found.

by M. Mertens, published on 10/31/2023

This challenge is a puzzle about a mysterious ciphertext, which is also protected by a clever disguise. Can you crack it?

by Nils Kopal, published on 10/28/2022

The Syllabary cipher seems to be just another substitution cipher, but is it? Find out and solve its mystery!

by Peter Uelkes, published on 10/14/2022

The legendary Merkle-Hellman Knapsack cryptosystem is not suitable for hiking, but it is considered a pioneer of asymmetric cryptography. Can you crack the ciphertext?

by Peter Uelkes, published on 3/26/2022

This challenge is about one of the oldest polyalphabetic ciphers. Can you crack this centuries-old puzzle?

by madness, published on 4/21/2021

The Wheatstone Cryptograph is a simple device that resembles a clock with two hands. For each hand there is a ring of symbols. Are you able to decrypt the given ciphertext?

by Viktor Veselovsky, published on 12/26/2020

This series deals with a grid — a basic tool cryptographers use to separate sequences of data into columns and rows. In this challenge you are given three grids where the first grid gives you hints to reveal the plaintext of the second grid. Are you able to find the right route?

by Viktor Veselovsky, published on 12/19/2020

This series deals with a grid — a basic tool cryptographers use to separate sequences of data into columns and rows. In this challenge you are given four grids where the first grid gives you hints to reveal the plaintext of the second grid. Are you able to find the right route?

by Viktor Veselovsky, published on 10/27/2020

This series deals with a grid — a basic tool cryptographers use to separate sequences of data into columns and rows. In this challenge you are given two grids where the first grid gives you hints to reveal the plaintext of the second grid. Are you able to find the right route?

by Miroslav Dimitrov, Bernhard Esslinger, published on 6/23/2020

Lattice-based cryptography schemes are relevant for current post-quantum cryptography research. This challenge series accompanies the basic theory from a chapter of the CrypTool Book called "LIGHTWEIGHT INTRODUCTION TO LATTICES". This part of the challenge series uses vectors to hide a famous quote in modern art. Can you reveal it?

by Miroslav Dimitrov, Bernhard Esslinger, published on 5/16/2020

Lattice-based cryptography schemes are relevant for current post-quantum cryptography research. This challenge series accompanies the basic theory from a chapter of the CrypTool Book called "LIGHTWEIGHT INTRODUCTION TO LATTICES". In this part of the challenge series we introduce systems of linear equations to find a hidden message in a picture.

by madness, published on 3/22/2020

This part of the challenge series is a warm-up with homophonic substitution. In a homophonic substitution cipher, there are more than one ciphertext symbol for each plaintext symbol. The key is a mapping.

by Joao Vaz Martins, published on 1/9/2019

Solving this challenge is not as hard as finding the needle in a haystack, isn't it?

by Joao Vaz Martins, published on 10/26/2018

Three messages were delivered — two encrypted, one in clear. Can you solve the puzzle?

by Chaoyun Li, published on 9/25/2018

The autokey cipher uses only a short keyword and the plaintext to encrypt messages. Are you able to break the given ciphertext?

by Chaoyun Li, published on 9/25/2018

What do you know about modular sequences? Work it out.

by Benjamin Strauss, published on 4/18/2018

How many experience points does Thomas need to reach the 200th level of his new computer game?

by Anna Lena Rotthaler, published on 12/8/2017

Little Anna has forgotten how to decrypt her ciphertext. Can you come up to her pre-Christmas wish?

by Andreas Kölblin, published on 11/16/2017

Are you able to crack the password of Radomil and find the missing 5 digits?

by Marc Gutgesell, published on 3/21/2016

This series consists of five parts which are based on each other and that will be getting more and more complicated with each part. This part is the actual challenge and tells you the New Year's greeting of the author.

by Marc Gutgesell, published on 3/21/2016

This series consists of five parts which are based on each other and that will be getting more and more complicated with each part. Part 4 contains a little New Year's greeting of the author and part 5 teaches us something about the weaknesses of this method. Part 3 adds another modification.

by Marc Gutgesell, published on 3/21/2016

This series consists of five parts which are based on each other and that will be getting more and more complicated with each part. Part 4 contains a little New Year's greeting of the author and part 5 teaches us something about the weaknesses of this method. Part 2 modifies the encryption of part 1 a little bit.

by Marc Gutgesell, published on 3/21/2016

This series consists of five parts which are based on each other and that will be getting more and more complicated with each part. Part 4 contains a little New Year's greeting of the author and part 5 teaches us something about the weaknesses of this method. Part 1 is the easiest part of this series.

by Joerg Gerschuetz, published on 11/20/2015

Both images in this challenge seem to contain no information at all. Or do they trick us? Find the secret message.

by Joerg Gerschuetz, published on 11/13/2015

The story of the simple bookseller Paul from Eisleben and his beloved from the near Castle Mansfeld will be continued: A second postcard has been found. Can you decipher the encrypted message?

by Jörg Drobick, published on 9/24/2015

The challenges for the simplified GRANIT cipher, a method that can be done manually, serve as an exercise and use an intentionally simplified version of GRANIT. Part 1 is a ciphertext-only challenge for which both permutation keys are known.

by George Theofanidis, published on 9/14/2015

How are the numbers interconnected? Can you find the three missing numbers?

by George Theofanidis, published on 4/16/2015

A friend of yours has given you the following text which contains only X and Y characters. He claims that this text contains a codeword. Can you find it?

by Bruce Kallick, published on 3/23/2015

How are the numbers linked? Can you find the two missing numbers?

by Bruce Kallick, published on 3/23/2015

How are the numbers linked? Can you find the two missing numbers?

by K. Schmeh, published on 12/23/2014

This is the beginner's challenge in a series about M-138, a manual cipher of the US army which has been relatively save at the beginning of world war 2nd. Part 1 of the series is a ciphertext-only challenge whose key is largely known.

by Bernhard Esslinger, published on 9/22/2014

You can find a short encrypted note at the end of the novel "Die achte Offenbarung" by Karl Olsberg. Decrypt the secret message!

by A. Wacker, published on 8/28/2014

This challenge is based on the Heartbleed bug in OpenSSL discovered in April 2014. Attack a server which is specifically prepared to be vulnerable to the Heartbleed bug. Please note that it is necessary to solve Part 1 first. !!! We had to take off this challenge, as our firewall doesn't allow flawed servers any more -- even if this flaw was offered by will for training and within a sandbox. !!!

by A. Wacker, published on 8/28/2014

This challenge is based on the Heartbleed Bug in OpenSSL discovered in April 2014. Attack a server provided by the group for Privacy and Compliance with the Research Institute Cyber Defence (CODE) at Bundeswehr University Munich, which is specifically prepared to be vulnerable to the Heartbleed bug. !!! We had to take off this challenge, as our firewall doesn't allow flawed servers any more -- even if this flaw was offered by will for training and within a sandbox. !!!

by George Lasry, published on 3/5/2014

In this part of this series of Enigma challenges, a plaintext message consisting of three letters which are repeated several times has been encrypted by the Enigma I. What are the first three letters of the plaintext?

by George Lasry, published on 3/5/2014

In this part of this series of Enigma challenges, a plaintext message consisting of three letters which are repeated several times has been encrypted by the Enigma I. What was the setting of the Enigma rotors?

by George Lasry, published on 3/5/2014

In this part of this series of Enigma challenges, a plaintext message consisting of two letters which are repeated several times has been encrypted by the Enigma I. What was the setting of the Enigma rotors?

by George Lasry, published on 10/28/2013

In this part of this series of Enigma challenges, a plaintext message consisting of one letter which is repeated several times has been encrypted by the Enigma I. What was the setting of the Enigma rotors?

by Sansibar, published on 10/28/2013

Two scatterbrained professors exchange messages that have been encrypted with the Trifid cipher. Unfortunately, one of them lost the second of three layers. Will he nevertheless be able to decrypt the message he received from his colleague?

by George Lasry, published on 9/26/2013

In this part of this series of Enigma challenges, a plaintext message consisting of one letter which is repeated several times has been encrypted by the Enigma I. What is the letter we are looking for?

by Emmanouil Doulgerakis, published on 9/4/2013

You find a note with strange characters and an unsolved Sudoku on your brother's desk. You are curious and would like to find out what your brother is working on. Can you decrypt the note using the Sudoku?