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We had an amazing turn out this year, with 177 of you making it through the final. Well done to all of you for an extraordinary performance. Whether you just took part in the practice rounds, or made it to the end, you have all joined that elite team of code breakers who have followed in Turing’s footsteps to tackle the great unknown. It is a fantastic achievement and I hope you will celebrate it in style.

I also hope you will come back next year and try to beat your own performance. If you made it to the end, you can try to be a little faster or a little more accurate next time. If you dropped out at an earlier stage maybe you can get a little further in 2019. As you can see below, some of our top competitors took part for years before winning a prize, and maybe that will be you next time!

But for now, it is my great pleasure to announce the winners of the National Cipher Challenge 2018:The Kompromat Files.

The Alan Turing prize, sponsored by GCHQ, is awarded to Zadok Storkey from Hills Road, known to you as RailFence. His painstaking crafting of the scripts that he wrote to tackle Vigenere type ciphers showed patience and cunning and he was the fastest qualifying individual competitor this year. He has participated in the National Cipher Challenge for the last two years and has enjoyed developing his own programs to break the ciphers. Following his A-level studies this year he expects to be starting a university degree in computer science, and we very much hope he will be following in Turing’s footsteps and taking a mathematical approach!

The Ada Lovelace Prize, sponsored by the British Computer Society, is awarded to Elizaveta Sheremetyeva from Oxford High School. She is known to us all as Chocologic.
Elizaveta is currently in Year 12, studying maths, further maths, biology, chemistry and physics, and somehow still found time to take part in the competition this year!
She is an experience competitor in the National Cipher Challenge and in recent years wrote a guide to cracking the hardest challenges/ This time she wrote a program to work out the keys to the keyed VIgenere cipher in Challenge 10B by guessing some of the words in the encrypted cipher. We had liberally sprinkled hints about Vigenere throughout the competition and as with other entries, Elizaveta used index of coincidence methods to work towards the solution. She avoided the trap we set with our very mean red herring pointing towards Playfair ciphers, which is a little disappointing. To those of you who fell into the trap – Muahaha!

The runner up prizes for the Alan Turing and Ada Lovelace prizes, are sponsored by Trinity College Cambridge and the University of Southampton. They are awarded to Jessica Richards (Onwards) from South Wilts Grammar and Jared Carter (Decrypting Ninja) from Peter Symonds College. Jessica is currently studying maths, further maths, chemistry and physics, and hopes to study some combination of maths and computer science at university. She has been taking part in the cipher challenge since year 7 and likes learning about cryptology and cyber-security. Jared is 17 and attends Peter Symonds College in Winchester where he is studying for A levels in further maths, physics and chemistry.
He is a keen climber and is ranked number one in England U19 for Squash. He has always been interested in ciphers, being inspired as a child by a trip to Bletchley Park and a series of books called Secret Breakers.

Jessica and Jared both used a similar method to Elizaveta to crack the cipher, using the word structure and the periodicity of the cipher to break it. Jessica is currently studying maths, further maths, chemistry and physics, and hopes to study some combination of maths and computer science at University. Given her prowess at both, we have no doubt she will do so with great success!She has been taking part in the cipher challenge since year 7 and likes learning about cryptology and cyber-security. Jared went one step beyond in his solution managing to find the two keywords (SHADOW and ARCHIVE) that defined the cipher, partly by “staring at the key table long enough”. As he said, this is a classic cryptographic decryption method, used extensively by Turing and the others at Bletchley Park! We are sure that some people will be kicking themselves for not guessing those particular key words!

The fastest team are awarded the University of Southampton prize, sponsored by the School of Mathematical Sciences. This year it is awarded to a team known to the world as E.Z.P.Z.L.M.N.S.Q.I.Z, who clearly felt confident from the start! Hailing from Angmering School the team comprises William Towler, and Oliver O’Toole. They used a simulated annealing algorithm to crack 10B. William had been paying close attention to our clues and was certain this would be a Playfair cipher, he writes that the team were “quite shocked to see the Digraphic Index Of Coincidence (used to identify substitutions of two letters – which is what the Playfair does) indicated it was nowhere near a Playfair”. Makes it all worthwhile! An amazingly fast submission from the team sealed top place on the leader board. Ollie and William are both in Year 12, with William studying A-Levels in maths, further maths, computer science, and french, and planning to study Maths at university. Ollie is taking A-Levels in maths, further maths, physics, and chemistry, and is planning to study engineering.

Just a little behind them we find the team “leaned” from Westminster. Anshu Banerjee, Daniel Kaddaj, Andrew Smith and Luke Remus Elliot used a statistical method to try to guess at keys to the cipher, scoring the result and improving it one step at a time by randomly changing the key. The effectiveness of the method is demonstrated by the fact that it tried only 50,029 keys before cracking the cipher, where the key space had over 10^186 possibilities. This team are awarded the IBM Prize.

Congratulations to all of our winners, to others who narrowly missed out, and to all of you who competed throughout this years competition.

For now the Elves will be taking a rest, while I help to organise the prize giving, which we expect to be sometime in the spring. We will get in touch with you when we have more news. After that it will be time to prepare the competition for 2019. We will be back in September, hope to see you here!

Apologies about the slight delay in announcing the winners and publishing the final leaderboard, they are both on their way. We are just waiting on final confirmation of some details from one of our winners. Do keep watching this space!


As they say in Hollywood – that’s a wrap!

Thank you to everyone who joined in this year’s National Cipher Challenge. It has been amazing to see so many of you do so well, and we hope you enjoyed the challenges and the opportunity to follow Jodie on her London adventures.

It has been an incredible year, with 7341 of you registered to take part and a record breaking number making it to the end. We will be contacting potential winners in the next couple of days to verify eligibility, and will make an announcement here next week. As a bonus we will also be posting a new challenge using the new and subtle Hutton cipher, which was designed by Eric Bond Hutton. It is closely related to the cipher we used for Challenge 10B (a keyed version of the Vigenere cipher) with a nasty twist. I don’t know of anyone who has cracked a Hutton cipher, so if you can do it you could make quite a name for yourself. No prizes for that bonus challenge, and no deadlines either, but if you work out a way to tackle it you might want to try to find Eric’s own challenge online. I haven’t looked recently, but he used to be offering $1000 to anyone who could break it. We will be asking our winners to give you some insight into how they cracked Challenge 10B so maybe that will help.

We will be organising a prize giving at Bletchley Park for later in the spring, and will post the details here and on Twitter so do keep an eye out.

It will take a while for the dust to settle on The Kompromat Files, but when it does the elves will be clearing out the website, and yes, we will be back for Cipher Challenge 2019 next Autumn! You may get a reminder about that before we delete all the user accounts, and we hope you won’t mind receiving a request for feedback on the competition too. Please feel free to delete it if you are not interested.

As usual it has been a pleasure to spend a few months exploring the world of codes and ciphers with you, I hope you will want to come back. Have a good year,


Congratulations to everyone who has made it this far …

Three challenges to go (8,9 and 10) and we still have loads of you on board. So far you have cracked Caesar shifts, substitution ciphers, some with little twists, and some devious transposition ciphers. Who knows what Douglas and Jodie have in store next!

Challenge 8 is the last challenge with a Friday night deadline for the first time band. For Challenge 9 you will find the time bands are now live. The maximum points for that Challenge will only be available until Midnight Thursday, so try to put some time aside to give it a go.

As a ‘heads up” the first time band for Challenge 10 in two weeks’ time will end at 8pm on the Thursday, and we will use “fastest first” in Challenge 10 as the tie breaker for the overall championship.

Good luck!