Harry

It's basically logarithms and lookup tables. Very elegant, but despite the fact that they were used extensively at NASA not really rocket science.

At the other end of the scale I have one of the models that was used by the Apollo astronauts. Not quite as big!!! Might be fun to get a photo of the two of them together?

We've a few tickets spare for the National Cipher Challenge event at Bletchley on 4th March. With speakers including Rob Eastaway. If you or your school took part in the competition in the Autumn, email us at cipher@soton.ac.uk with your details so we can see if we can fit you in.

Is it because the National Cipher Challenge is over and the long wait to the next one has just begun?

I know, and will contact her too, but the skill of a puzzle master lies in the taste and judgment in selecting them so I am hoping you both should have something to offer!

Slow to pick up on this, but thank you for your lovely solution. Perhaps we could chat about next year's competition some time? It would be nice to have a guest puzzle setter at some point!

Pick up the dollies and take a deep breath! You know you can do this!! Have you looked at the letters that go wrong? And have you inspected the grid in the Casefiles?

At the moment the only order is by score and you can't conclude anything within the same score (=1st etc). For the very final overall leaderboard we will separate out the special few awarded prizes at the top.

That would be great! Not sure we can do it at the moment, but will ask the developers!

National Cipher Challenge An annual codebreaking competition for UK schools and homeschooled students run by the School of Mathematical Sciences at the University of Southampton

We are looking forward to the launch of the official competition challenges at cipherchallenge.org at 3pm this afternoon. If you want to find out why the three Charles (Babbage, Dickens and Wheatstone) need to talk to the US president, there is only one way to find out!

National Cipher Challenge An annual codebreaking competition for UK schools and homeschooled students run by the School of Mathematical Sciences at the University of Southampton

Just like last year we broke the records for Challenge 2 entries with nearly 8100 of you signed up to take part. Practice Challenge 3 starts at 3pm today, so if you haven't signed up yet head over to cipherchallenge.org to get involved

Excellent! Hope you all have fun!

National Cipher Challenge An annual codebreaking competition for UK schools and homeschooled students run by the School of Mathematical Sciences at the University of Southampton

The clock is ticking down to the 3pm start of Practice Challenge 2 at cipherchallenge.org! We had over 7000 registered for the first round and there is still time to register for the competition. Hope to see you there!

The best of times - Challenge 1 form cipherchallenge.org, featuring a playing card depicting Charles Dickens as the Jack of Clubs

We couldn't be happier with the response to the first cipher challenge this year. Over 7400 signed up already and we're still on the 1st practice challenge! Head over to www.cipherchallenge.org/ to to get your students signed up in time for the 2nd practice challenge tomorrow.

National Cipher Challenge An annual codebreaking competition for UK schools and homeschooled students run by the School of Mathematical Sciences at the University of Southampton

Over 5000 already registered at www.cipherchallenge.org ready for the practice challenges to start tomorrow at 3pm. If you are aged 11-18 and want to learn codebreaking and show the world what you can do then head over and sign up!

Love it! Would also love it if any musical cipher challenge aficionados out there feel like adding to our collection of themes!

The 24th National Cipher Challenge is now open for registrations and we have already had 1200 sign ups. The competition starts on October 9th, so there is time to register your teams and get them investigating codes and ciphers. Catch up on our news at www.cipherchallenge.org.

Day 1 and we have reached our first 500 registrations at www.cipherchallenge.org already! Will we beat last year's record 9,000? That is up to you!

Ready to register for the National Cipher Challenge? The site opens tomorrow. Did you know that as a teacher you can monitor the teams at your school? You will be able to read more about that at www.cipherchallenge.org/how-to-bulk-...

Registration opens 18th September 2025. Competition starts 9th October 2025.

Just a few days now until the 2025 National Cipher Challenge opens for registration! If you know someone aged 11-18 who might like codes and ciphers (or who might not yet know that they do!) then get them to take a look at www.cipherchallenge.org on Thursday.

Tom, this looks great! Congratulations!

Meet some of the Cipher Challenge community ... - National Cipher Challenge 2024 Your stories about taking part in the competition.

We are looking for additional content to add to our Community page. You can read last year's at 2024.cipherchallenge.org/boss-your-ci...
If you took part and would like to feature on this year's site, then do get in touch either here or by email at cipher@soton.ac.uk. We would love to hear from you!

Registration opens 18th September 2025. Competition starts 9th October 2025.

Posters for this years www.cipherchallenge.org should be arriving in schools this week. If you want to help promote the competition, why not post a picture of the poster on your boards?

Yes! Should arrive in schools for around 8th Sept!

Holding a Clubs/Societies/Enrichment Fair for your school or college? The National Cipher Challenge might be just what you need. Here is a poster you can use to promote it! The site will open for registration on Sept 18th and the competition starts Oct 9th. Challenges weekly throughout term!

Thank you! We will soft launch around 18th Sept for registration, with all the usual resources available then. Competition starts with the usual practice rounds from 9th Oct.

Yes it is! Posters are stacked ready to go out, and the website is being updated. We really hope you like it!

The National Cipher Challenge – More Than Just Codebreaking I’ve been meaning to write about how I got into codebreaking — so here’s the start of a small series on maths, ciphers, and curiosity. A lot of experiences have shaped the curious, questioning pers…

Want something to read on these idle summer days? You could take a look at this short article by one of our cipher challenge competitors: mathsrant.com/2025/07/28/t...
(Not that the Elves at CC HQ are idle. Far from it - too much to be done in prep for the new adventure. More soon!

It's true that you sometimes need to generalise a conjecture in order to prove it, but as a general principle I think "generalise then prove" (rather than "prove then generalise") is what Sir Humphrey might call "brave".

Just a heads up that now the challenge is finished we are working on the leaderboards, prizes and invitations to the National Cipher Challenge event @bletchleypark. Please do keep an eye out for messages from us on the site, and log in regularly to see if we have left one for you in your account!