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The Lighthouse Conspiracy

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Until we meet again …

Well, that was fabulous. We had 6,250 of you taking part this year and it was a privilege and pleasure to join you in the adventure. We hope you enjoyed the competition as much as we […]

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Challenge 10B – the grid!

Here is the final grid for the message left by the Lighthouse Keepers. The word “conspirators” is probably still apt, but it doesn’t feel fair now I know what they have been doing. It still leaves […]

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Challenge 10B – got it!

i was right, and this is a non-standard Playfair cipher. Pairs of letters in the same row OR the same column both get shifted vertically, rather than using the left right rule on a row. It […]

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Challenge 10B – second (third?) thoughts

Maybe it was too big an assumption – there are lots of pairs XY with both elements coming from the bottom row. Unless this is a very unusual text there are far too many to get […]

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Challenge 10B – the second breakthrough

I am making a big assumption here, but I think it it is worth it. Always best to try something rather than just stare at the cipher text, so here goes: With the digits 4-9 on […]

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Welcome to the 20th National Cipher Challenge

The website is now open for registration and you are welcome to dive right in. There is loads to explore, with lots of information about the competition, how to register and take part, and information about how to start breaking codes and ciphers or to improve your skills.

If you have questions then head over to the forum to post them. All registered participants (and teachers) can do that and there is an active community of cipher challenge alumni and forum moderators (the Elves) who are waiting to help. Harry or Jodie might even reply themselves.

It is great to welcome you to the National Cipher Challenge family for this special edition of the competition. We hope you enjoy it,

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