On the first day of the Computer Science trip, we visited the National Museum of Computing, where we took part in a variety of activities. Our first session focused on the power of prime numbers and their role in encryption. We learned how prime numbers make ciphers nearly impossible to brute force (i.e., trying all possible combinations). This is achieved by ensuring the number of teeth on the encryption cogs are prime, making the process significantly more complex and time-consuming to crack.

Next, we moved to a different room where we answered quiz questions and had the rare opportunity to use a fully operational Enigma machine. After that, we took a tour of the museum, where we saw Colossus—a massive computer used to break the Lorenz cipher, which was even more complex than Enigma. The Lorenz cipher had 12 wheels, all prime numbers except for two, resulting in approximately 1.6 quadrillion possible starting positions. However, it was ultimately cracked when two messages were mistakenly sent using the same key (i.e., the machine was set up in exactly the same way for both messages).

On the second day, we visited Bletchley Park, which, for me, was the highlight of the trip as it was more history-focused and highly informative. We started with a session on encryption and decryption, learning how two people could securely exchange secret messages. We then explored the exhibits, where we gained insight into what it was like to work at Bletchley Park and how secretive the operation was. Before even being told what their job entailed, new workers had to sign the Official Secrets Act. This meant they could only communicate with the people in their assigned hut and were prohibited from discussing their work with friends, family, housemates, or even other Bletchley Park employees outside their group.

Bletchley Park employed around 10,000 people, including some of the brightest minds from Oxford and Cambridge. Interestingly, the majority of workers were women, as many men were away fighting in the war. While many assume Bletchley Park was solely home to codebreakers, other essential roles such as filing, cooking, and general maintenance were just as crucial in keeping the operation running.

To conclude our visit, we took a guided tour of the grounds, where we learned why Bletchley Park was chosen as the site for these operations. The mansion was surrounded by a large area of land, providing space to construct additional huts for workers. Its location between Oxford and Cambridge also made it an ideal hub, as it allowed for easy transportation of professors and top students recruited for codebreaking efforts.

Aiden Clarke