Welcome to the National Cipher Challenge, a competition designed for pupils aged 11-18 across the UK and intended to stretch and entertain them. Those who already enjoy puzzles will certainly find something rewarding here, but we hope that its blend of imagination and creativity might attract some others too. It is written by people who love mathematics and would like to communicate the joy of it to the next generation, but you don’t have to be a natural (or to know that you are!) to take part. A surprising number of people who thought they did not like maths discover a love of it through the competition. You also do not need to remember everything you have been taught in lessons to crack these challenges. We have written a guide to get you started, and it is more about persistence and creative problem solving than technique. Of course, like everything, the longer you take part in the Challenge the more you will hone your skills. Even if you don’t complete all the stages this year, you will find it easier next year and we hope you will enjoy the experience of rising up the leader board each year you take part.
For those of you who are new to the competition we have put together a page of stories from participants and teachers who taken part in previous competitions. We hope they will give you a flavour of the competition, and an idea of what schools and participants can get out of it. If you have your own story about the competition, do get in touch we would love to hear from you. And if you have questions about it then email us at [email protected] and we will do what we can to help.
The How to… menu contains links to a number of guides including how to register an account or for a teacher account; bulk register or monitor teams. It also has information about how to submit an entry, get feedback and download certificates.while the Find out More menu has links to loads more information, including the ever helpful FAQ.
The BOSS Training Division Page contains a wealth of material about codebreaking and some additional guides to programming and codebreaking. There is a library with suggestions for books you might enjoy, including some recommendations from Anthony Horowitz and the Book Brothers. Many of the books are available for download on Apple Books and on Amazon. Youtube is also full of useful videos on codes and ciphers and we have listed some in the cinema section.
Please feel free to add suggestions for the resources on the forum. (You can register for your own account to post on the forum even if you are not the one taking part.)
If you have any questions please do post them in the forum, or get in touch by email at
You can register a teacher account below. This will allow you to follow the progress of your teams; just ask the team captains to give you their special PIN codes, which they will find in their account pages and add them to your own account page to see their achievements listed.