Here you can use several codebreaking tools to help you decipher coded messages. You can either use one of the ciphertexts already here or you can enter your own ciphertext. If you have a ciphertext of your own that you would like to decipher, then you can go straight to the relevant tool. If you do not know what kind of cipher was used, then your first task will be to guess. (Alternatively, you can use the frequency analysis tool to make an informed decision.)
You can choose a tool from the menu on the right.
Each tool takes you through the job of deciphering the ciphertext in several stages. You should be able to move back and forth between these stages (and even back and forth between different tools) without losing your work. All the information about your current session is stored, and should not be lost whilst you are still connected to this site.
For the tools to work properly you must have cookies enabled in your browser.
Some of the tools use the convention that ciphertexts are written purely in capitals, and plaintexts are written purely in lowercase letters, so when you enter a ciphertext make sure that it is all in capital letters.
None of these tools can decipher coded messages automatically. However, they enable you to work much more quickly than by hand. In particular, they make it easy to experiment.