Downe House pupils scoop top award at Bletchley Park
Two promising young women at Downe House School, Cold Ash, have achieved an outstanding feat.
Year 13 pupils Melinda and Dasha entered the 21st National Cipher Challenge competition, organised by the University of Southampton, at the beginning of September.
And they have now come in joint second after qualifying in the top 20 — out of more than 7,000 registrations.
The girls received their accolades at a special awards ceremony on Tuesday, February 7, at Bletchley Park, Buckinghamshire – famed as the centre of the Allies' codebreaking operations in the Second World War.
Other teams from the school entered, but only their's persisted through to the final round.
Under their team name – the 'Downe House Pig Farming Society' – the girls competed in a series of 10 progressively complex online challenges, testing their speed and accuracy.
"They have a website where they release two paragraphs of text every week," explained Melinda. "They are encoded by different methods and we decode them and submit the answers.
"It's anonymous until you get to the prize giving and people find out what schools each other are from."
The girls also competed last year and explained how part of the competition's appeal is unravelling the story revealed through each new cipher.
Attendees of the ceremony enjoyed a tour of the park, followed by an afternoon of lectures by guest speakers.
Dasha said: "I find the history behind Bletchley Park and cryptography very interesting."
"There was another cipher called the Lorenz cipher," added Melinda. "But people only know about Enigma. So, we got to find out about something lesser known."
What techniques did they use to approach each cipher?
"There are standard methods of analysing a cipher text when you don't know what it is at all," explained Melinda.
"There's either substitution, where each letter is replaced by another encoded letter.
"Or it's transposition, where the letters are just jumbled up in a way, so you can do a frequency analysis of each letter's occurrence and if it matches with the English alphabet, then it just got jumbled up, it didn't get substituted.
"And if it did get substituted, then you find out. Because E in English is the most frequent one. But if it turns out that Z is the most frequent, then it might be that E has been substituted by Z.
"But the organiser always makes it really hard with the last one. If there's a standard method of encrypting, they will change it.
"So, all the existing websites won't work and you have to do it by hand. Or code your own programme."
Are there similarities between their decryption methods and those used during the war?
"There's basic techniques like cribbing. We did use that for our last challenge," said Melinda.
She also explained how the Bletchley machines used a surprisingly large amount of technology for their time.
What are their views on Prime Minister Rishi Sunak's recent announcement to continue maths education in some form for all pupils until the age of 18?
"I think it depends how much maths, because I know a lot of people couldn't really cope with maths after GCSEs," said Melinda. "Not every subject is for everyone, and that's okay.
"If it takes up one of your three A-levels, then I think it's quite limiting if you only want to study one subject or are applying for a joint honours degree.
"But if it's half an A-level, like an AS, then that's a bit different."
This competition marks the last for the girls, as participants must be in full-time or further education.
They are both immensely proud of their result and are currently considering leading an assembly after half term to inspire younger pupils to take part.