Can you work out what size grid you need to read our secret message?
How can Agent X transmit data on a faulty line and be sure that her message will get through?
Substitution and Transposition all in one! How fiendish can these codes get?
Time for a little mathemagic! Choose any five cards from a pack and show four of them to your partner. How can they work out the fifth?
The Enigma Project's James Grime has created a video code challenge. Watch it here!
Simon Singh describes PKC, its origins, and why the science of code making and breaking is such a secret occupation.
Our toolkit removes the drudgery of codebreaking while leaving you to do the hard thinking!
Here is the start of a six-part challenge. Can you get to the end and crack the final message?
Find the frequency distribution for ordinary English, and use it to help you crack the code.