iiinova — where your digital self keeps evolving

Harry

@cipher-challenge.bsky.social

172 followers 28 following 95 posts

Join Harry at the National Cipher Challenge, which invites school-aged participants to put their code-breaking skills to the test every Autumn. Created by the School of Mathematical Sciences @UniSouthampton.

Posts Replies Media

Harry @cipher-challenge.bsky.social · 18/09/2026

Ssh don't tell*, but cipherchallenge.org has soft-launched for a week of bug hunting before we go live with the 25th National Cipher Challenge! Registration opens 24/09, competition starts 08/10, but if you want a sneak peak ... *Actually, please tell everyone!

Harry @cipher-challenge.bsky.social · 13/08/2026

Thinking of all our Cipher Challenge alumni getting their results today, and the teachers and family who support them. Congratulations to all of you on getting to this point and wishing you all the very best in the next stage of your adventure wherever it leads!

Harry @cipher-challenge.bsky.social · 09/07/2026

Quick request for all the teachers out there who love the National Cipher Challenge. We will hold our 25th prizegiving at Bletchley Park in early 2027. Which of the following dates is best? 10th February (before half term) or 4th March (after half term).

Harry @cipher-challenge.bsky.social · 13/02/2026

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.

Harry @cipher-challenge.bsky.social · 06/11/2025

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!

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 23/10/2025

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

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 16/10/2025

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!

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 15/10/2025

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.

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

Harry @cipher-challenge.bsky.social · 08/10/2025

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!

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 22/09/2025

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.

Harry @cipher-challenge.bsky.social · 18/09/2025

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!

Harry @cipher-challenge.bsky.social · 17/09/2025

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-...

Harry @cipher-challenge.bsky.social · 15/09/2025

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.

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 12/09/2025

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!

2024.cipherchallenge.org

Meet some of the Cipher Challenge community ... - National Cipher Challenge 2024

Your stories about taking part in the competition.

000

Harry @cipher-challenge.bsky.social · 08/09/2025

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?

cipherchallenge.org

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

000

Harry @cipher-challenge.bsky.social · 02/09/2025

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!

Harry @cipher-challenge.bsky.social · 12/08/2025

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!

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…

Harry @cipher-challenge.bsky.social · 11/01/2025

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!

Harry @cipher-challenge.bsky.social · 14/11/2024

We are well underway with the competition at www.cipherchallenge.org, though it is not too late to get involved if you fancy it. You'll be joining over 8500 other participants & there are still 6 challenges to break over the next few weeks. The next one goes live at 3pm today. Hope to see you there.

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 07/11/2024

Over 8,000 signed up ready to take part in the competition at cipherchallenge.org this year! The first competition challenge runs until next Wednesday, so it is not too late to join in. Hope to see you there!

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 24/10/2024

We have over 8,000 subscribers for the first time ever.They are all beavering away at cipherchallenge.org and putting a LOT of pressure on the marking system. If you get errors submitting, then it may be worth waiting. It won't affect your marks and will give the chips a chance to cool down!

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 23/10/2024

Tantalisingly close to 8,000 users registered at www.cipherchallenge.org with just over 24 hours to go til we publish the final practice challenge. Competition challenges start on November 7th, so if you want to join the fun head over to cipherchallenge.org and sign up! Teams or individuals welcome.

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 21/10/2024

Half way through Challenge 2 in this year's National Cipher Challenge and we already have over 7,800 participants. Will we break 8000? It's possible, the first 3 challenges are for practice and we usually get a bunch more signing up at the 4th round. Head over to www.cipherchallenge.org to see why!

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 17/10/2024

Challenge 2 is live and we look forward to seeing what you make of it. These are still practice rounds, so we're trying to make them accessible to complete newbies. If you have more experience then avoid using the support we put in place at cipherchallenge.org and see how fast you can break it.

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 17/10/2024

Challenge 1 is now complete and the leaderboard will be published at 11am this morning. If you can't wait to see how you did then log in at www.cipherchallenge.org and download your certificates for part A and part B to find out. And don't forget, Challenge 2 goes live at 3pm this afternoon

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 16/10/2024

Last day to submit entries to Challenge 1 at www.cipherchallenge.org. If you don't make the deadline 11pm tonight the next practice round goes live tomorrow at 3pm. If you miss that there's still time to register & compete in the other rounds, with prizes based on your scores in rounds 4-10.

cipherchallenge.org

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

000

Harry @cipher-challenge.bsky.social · 14/10/2024

A couple of days left to tackle the first practice challenge at www.cipherchallenge.org, but even if you can't join us yet there is plenty of time to get ready for the main competition challenges starting on Nov 7th. All are welcome!

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 11/10/2024

At the end of round 1 last year we had 5800 competitors signed up. Here we are on day two with over 6500 already taking part in the competition at cipherchallenge.org. If you want to see why, head over and take a look. There's still time to join in!

cipherchallenge.org

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

000

Harry @cipher-challenge.bsky.social · 11/10/2024

The team at www.cipherchallenge.org love exponentials!

000

Harry @cipher-challenge.bsky.social · 10/10/2024

It's a living breathing thing: www.cipherchallenge.org

Harry @cipher-challenge.bsky.social · 10/10/2024

While the majority of the cipherchallenge.org competitors come from the UK we have a number from UK schools overseas and even some who take part "just for fun" from around the globe. We thought you might like to see where they are, so courtesy of Google Analytics, here is a map:

Harry @cipher-challenge.bsky.social · 09/10/2024

After reaching 444 teacher registrations earlier this week we're now at a total of 5555 registrations (competitors and teachers). Head over to cipherchallenge.org to break the symmetry or get us up to 6666! (as in the 4-digit number, not its factorial, that would be, to say the least, implausible.)

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 09/10/2024

444 #teachers have signed up for the National Cipher Challenge at www.cipherchallenge.org, which has a pleasing symmetry, but we would love more of you to discover what the competition has to offer your #maths and #computing pupils. So do head over to see if it might appeal.

cipherchallenge.org

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

000

Harry @cipher-challenge.bsky.social · 08/10/2024

5,000 sign ups and climbing ... How many will we get before the competition start on Thursday? www.cipherchallenge.org

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 08/10/2024

If you want to see how your students are getting on at www.cipherchallenge.org then you can register an account and give them your monitoring PIN to add them to your list. Read more about it at www.cipherchallenge.org/how-to-bulk-...

cipherchallenge.org

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

000

Harry @cipher-challenge.bsky.social · 07/10/2024

Just 2 days 3 hours and 15 minutes until we launch the first challenge at www.cipherchallenge.org so we hope you are all registered or about to do so. If you need something to keep you occupied until then, then take a look at our News page or the puzzles section of our Forum for some ideas!

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 28/09/2024

Just to say that we are trying to be a bit more disciplined with News items at www.cipherchallenge.org this year. Aiming for about one a day, but always willing to consider extras, so if you come across something you think we should highlight, get in touch. You can mail us at cipher@soton.ac.uk.

cipherchallenge.org

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

Harry @cipher-challenge.bsky.social · 24/09/2024

Over 2000 competitors in over 1000 teams signed up so far for this year's National Cipher Challenge. If you haven't registered yet, head over to www.cipherchallenge.org to join in the fun. The first challenge will be published on October 10th, so you still have time to get ready, but don't be late.

cipherchallenge.org

National Cipher Challenge

A free online codebreaking competition for schools and colleges

Harry @cipher-challenge.bsky.social · 13/09/2024

The cipher challenge crew's favourite team name so far is "AbelianAussie". That is one heck of a commute! (math joke)

Harry @cipher-challenge.bsky.social · 13/09/2024

Looks like the site has woken up! www.cipherchallenge.org is the new place to hang out (if you like breaking ciphers that is!)

Harry @cipher-challenge.bsky.social · 12/09/2024

Closing in on the first 100 teams to register at cipherchallenge.org this year. How many more on day one?

100

Harry @cipher-challenge.bsky.social · 12/09/2024

We are up and running! The new cipher challenge website is open for business, so head over to www.cipherchallenge.org/account-login/ and register for an account. The competition launches on October 10 so you have plenty of time to familiarise yourself with the rules. We look forward to meeting you!

000

Harry @cipher-challenge.bsky.social · 09/09/2024

Posters for this year's National Cipher Challenge are arriving in schools now so please check your pigeonholes! Would love to hear from you, so like if you have received one. www.cipherchallenge.org will open for registration on 12/09/24 and the competition starts on 10/10/24

cipherchallenge.org

100

Harry @cipher-challenge.bsky.social · 28/08/2024

Anxiously waiting for your cipherchallenge.org poster? They are all bundled up ready to go! If you use it on a display, do post a picture, we love to see them. (Thanks to our friends at Document Despatch for all their hard work on the mailing.)

Harry @cipher-challenge.bsky.social · 21/08/2024

Wondering what and what not to do if you get an A4 envelope in the post that looks like the attached? Some advice 1) Don't sigh/complain about the growth in junk mail 2) Admire the typography 3) Open the envelope & take out the poster inside 4) Find a spot to put it up where your pupils will see it

A white A4 envelope in landscape, with the logos for: the 23rd National Cipher Challenge; the organisers at the University of Southampton; the sponsors - GCHQ, Ten Degrees, Netcraft, Trinity College Cambridge, EPSRC, Northrop Grumman and the Bluespark Foundation. The competition opens for registration on 12th September 2024 and starts on 5th October 2024. It is a free online codebreaking competition for UK School and 6th form college aged pupils. It awards online certificates, medals and cash prizes, with a £5000 prize fund. The National Cipher Challenge is run by the School of Mathematical Sciences at the University of Southampton

Harry @cipher-challenge.bsky.social · 20/08/2024

For those new to the National Cipher Challenge a primer What: an online codebreaking competition for UK schools, 6th form colleges & home schooled students. When? 12/09/24 - 06/01/25 Where? www.cipherchallenge.org Why? An enrichment activity aimed at stretching pupils, whatever their ability. (1/7)

Harry @cipher-challenge.bsky.social · 19/08/2024

As a thank you to our early followers, and an inducement to the rest, here is an early glimpse at the poster for this years #cipherchallenge, The Mystery of the Silver Bullet.

Kate knew guns but nothing about ciphers, so the inscription on the bullet was a mystery. Needing help to decipher it, she wrote to the one woman on earth who might know how.
Join Ada Lovelace, Kate Warne, and Charles Babbage to help them solve
The Mystery of the Silver Bullet.

A codebreaking competition for UK schools and colleges, from the School of Mathematical Sciences at the University of Southampton. Hosted at https://www.cipherchallenge.org

Registration opens 12th September
Competition starts 10th October

£5,000 in prizes to be won

Harry @cipher-challenge.bsky.social · 19/08/2024

Welcome to our new feed, if you were already following us at "the other place" or are new to the National Cipher Challenge we look forward to getting to know you. You can find out more about the National Cipher Challenge at www.cipherchallenge.org. Do get in touch! Harry

cipherchallenge.org

The 2023 website is available to view to see last year's challenges: 2023.cipherchallenge.org