Thank you so much to all of you for your patience, enthusiasm, doggedness and skill. I hope you enjoyed this year’s National Cipher Challenge as much as I enjoyed setting it. Of course while the challenges are over there is still much to do. Winners for example will need to be selected and notified, the leader boards published and Prizegiving event will need to be advertised and run. I suspect that some of you will still be scratching your heads over one or two of the challenges themselves, even with the plaintext to guide you, so please do come back next week for news and info about the competition. We will publish information about the winners (and the final standings) next Thursday.

We will be contacting possible winners early next week to verify details. If you think you might be in with a chance then be ready to answer questions about your submission!

Thank you again for making this year’s challenge such a success. We had hoped for around five to five and a half thousand participants and you smashed that number. If you have friends who might enjoy it next year then do make sure they know about it.

Happy New Year,

Harry

Challenge 8 is just two hours away and we have 47 teams in joint first place, but there are a ton of points available for Challenge 8B and just maybe one of the lower ranked teams will sneak through to beat them all. It might be you!

We are amazed and delighted at the response to the competition this year. At the last count we had 7622 registrations organised in 4396 teams. They made 17295 submissions across the competition so far, including 1322 for Challenge 7, of which 599 were for Challenge 7B. They have cracked Caesar shifts and affine ciphers, keyword substitutions and Vigenere ciphers, column transpositions and even the notorious bifid cipher. And this afternoon they will be trying to crack a (whoops, almost told you! No clues yet!) Everyone who has tackled any of them has joined an elite group of Cipher Challenge alumni that includes some of the UK’s leading cyber security experts. Don’t forget to put it on your UCAS statement!

There will be time for thanks later (after the end of the Challenge in January) but I do want to wish you all, competitors and members of the Cipher Challenge family, a very happy Christmas (or festival of your choosing). Enjoy Challenge 8, but don’t forget to take some time out to enjoy the holiday with your family and friends. (And for your new friends here at the Challenge there is a new forum topic as a place to send them Cipher Challenge season’s greetings.)

Best wishes,

Harry

Another fantastic week with loads of you managing to crack a Vigenère cipher, perhaps for the first time. Challenge 7 is now live and we have 172 of you downloading it right now. Good luck. We are not giving much help with this at first. It will be interesting to see what you make of it, but it is really tough. We will start giving out hints this weekend, so keep an eye out for Joan’s posts there. We will also tweet when clues go live, so follow us @cipher_master to get early warning.

Congratulations to everyone who cracked Challenge 5. Part B was particularly difficult as Trinity had used a column transposition cipher in which she read off the cipher text down the columns rather than across the rows. This makes it harder to use cribs (like the names Jamelia or Dynamix) in that the letters of those words can get spread far apart. On the other hand you can use that fact to try to find the length of the keyword by looking, for example for places where the letters are still close. Joan Clarke gave some really good hints about this in the forum this week, and you can find a description of how to tackle these ciphers in my Beginners’ Guide.

Many of you will probably need help with this week’s challenge too. Again Joan will be on hand to give tips, just keep an eye on the forum. No hints from her before the first deadline at midnight on Friday though!

Good luck