The National Cipher Challenge 

Do you and your pupils love a challenge? Have you thought about taking part in the National Cipher Challenge


What is the National Cipher Challenge?  

The National Cipher Challenge is a free to enter, national competition which has been run by the University of Southampton for over 20 years. The competition normally begins in early October, with registration opening mid-September, and is aimed at Year 7-13 pupils. Every week a new encrypted text is released, all themed around a story which is often linked to real historical events.  The competition feels like an immersive adventure, with all the materials designed to feel authentic. The first-rate design of the competition is impressive, and will appeal to pupils who are used to playing computer games with high quality graphics.   


How many rounds are there? 

The first three rounds are ‘practice rounds’, and there is a certificate for every pupil who completes any one of these rounds. There are usually around 10 rounds in total, which increase in difficulty. If pupils can crack round four there is a Bronze certificate available and after that, subsequent rounds will attract Silver or Gold certificates.  


What are the prizes? 

For those who win the whole competition there are prizes of up to £1000.  Pupils can enter as individuals or in teams – if they enter as a team then the prize money will be split amongst the team. With several thousand entrants each year, most won’t win the main prizes – but that is not the point. Pupils and teachers alike become passionate about solving the ciphers, and taking part in this competition is extra-curricular maths at its most engaging.  

There are also certificates available for every completed round and a leader board. (Teachers do need to be aware that pupils need to download the certificates themselves from their pupil accounts).  


How could the National Cipher Challenge work as part of a maths club? 

The National Cipher Challenge is perfect for maths clubs, but could also be run as part of normal maths lessons. Team composition is flexible so you could easily have pupils in Year 9 working with pupils in Year 10. It is also possible to enter more than one team, or individual pupils. There is a wealth of training resources including six downloadable lesson plans which cover some of the most popular ciphers.   

If you are running the National Cipher Challenge for the first time in your school, then it is hard to predict how far your pupils will get. You can however be confident that pupils will be able to tackle the first three practice rounds as well as having a go at round 4.  So why not plan four weeks of your maths club around the challenge - if you get beyond that it will be brilliant, but you know for definite what you are doing for the first four weeks.   (You could also aim to improve your record each year).


What if my pupils get stuck? 

In the first three practice rounds you can get hints and there is also a forum which teachers can use throughout the competition. The six downloadable lesson plans cover all the skills needed to tackle the first three challenges. There is also a substantial collection of other training resources which are available on the website.  Your pupils will be well supported in the National Cipher Challenge.  


Do my pupils need computer programming skills to crack the codes? 

All the ciphers can be cracked without the use of a computer, however in some of the much later rounds pupils will be faster if they use some basic programming skills. This could be a good opportunity for collaboration with your computing teachers.  


What if I need to miss a week? 

If you miss a week, you can simply pick up the next challenge with your pupils. You won’t be able to get the points from the week you missed, however it won’t damage your enjoyment of the competition.  


Why is the National Cipher Challenge great for my pupils? 

Your students will be using skills they already have and applying them in a totally different way. This competition is fun, challenging and will undoubtedly be one of the most memorable things you do as a teacher this year. It builds the soft skills of teamwork, perseverance and creativity. Your sixth formers can talk about it when applying to university. For some pupils it may inspire them to study maths at A-level, degree level or to pursue a career in cyber security. The benefits are endless – but deep down, everyone loves a good puzzle and so hopefully you won’t be able to resist entering your pupils for the competition!  

Any queries about the National Cipher Competition should be directed to Prof Graham Niblo at:  



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