An encryption machine that looked a little like a typewriter, known as the Enigma machine, was invented in the 1920s and was used by Germany during the Second World War. When a message was typed into it, a series of rotors scrambled it into cipher text to keep the communication secret.

The Enigma machine encryption was extremely complex, with so many possible combinations that many people believed it was unbreakable. What’s more, the key code was changed daily at midnight. However, a group of people still worked tirelessly to try to crack the code. Alan Turing (see here) and his colleagues at Bletchley Park, in England, had an Enigma machine and an electromagnetic machine called a Bombe.

By putting in short parts of a message, known as cribs, that they had already been able to decipher, they were able to use the Bombe to disprove incorrect settings and find the correct ones. It is said that this top-secret project to crack the Enigma code helped to shorten the Second World War.

Computer Encryption

Information can now be encrypted and decrypted by computers in the blink of an eye – the internet, banking details, emails – all encoded in more and more complex ways. Sometimes, these codes are cracked by hackers, who have to use evermore ingenious ways of getting the information.