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National Cipher Challenge 2019

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Cutting Edge Cracking

One of our competitors, Cribbage, from the 2018 competition kindly wrote up how they tackled the final challenge last year. If you are wondering what it takes to decipher a message encrypted with a brand new code then this might give you some idea. The challenges in the early rounds of the of this year’s competition won’t be anything like as difficult, but as for the later ones…

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Rules of Engagement

While we try to keep things simple and friendly, the competition has some rules and you should probably know about them. We think they are clear, and they are certainly tested by time, but if you have any questions about them do contact us and we will try to get back to you within 24 hours. In the meantime you can read them here.

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Programming for Code Breakers

National Cipher Challenge alumnus Julian Bhardwaj wrote a rough guide to computer programming for code breakers which he has kindly allowed us to post here for you. You don’t need to be a world class programmer to do well in the challenge, you can get a long way with a word processor, a spreadsheet and some cunning, but it really helps to automate the routine jobs, and these notes will get you started.

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A free beginner’s guide to code breaking to get you started

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Anthony Horowitz Tweets



Welcome back to the National Cipher Challenge, I can’t believe we are now in the 18th year of the competition. Back in 2005 we travelled with Harry deep under the Arctic to the Lomonosov Ridge, as he worked to recover a Soviet spy satellite that had crashed in the northern waters. The mission took place in 1957 and this year’s competition starts as Harry returned to the US to receive his new assignment. You will be working with him to … Read on


Each challenge B has a set of time bands that are used to award points for speed. These are published on the Challenge page, HOWEVER, we have not yet decided on the points for challenges 2-9 and those schedules will be updated over the next few weeks. The time bands for Challenge 1 are fixed and will not be changing. We just wanted you to know you should take the others with a pinch of salt for now. Harry


Our web team at 10Degrees make every effort to ensure that their work is widely accessible and we and they thought you might like to know how they do that. Beyond the technical side of reviewing the site structure and html, we also take neuro-diversity issues seriously, and, as the team says below, if there is anything we can do to make the competition more accessible for you or for someone you know, then please get in touch. You can … Read on