Teacher Chris Leach shows us some excellent activities that show there’s so much more to secret codes than spies wearing trench coats.
When I was in primary school one of my favourite books was a handbook on how to be a secret agent. Up until then I’d always believed that codes were just used by spies, wearing long trench coats, meeting on park benches and using sleight of hand to pass on top-secret messages. The book also included information on Semaphore and Morse Code though and that’s when I began to understand that codes and ciphers were not just used to hide secret messages.
Codes and ciphers
Let’s start by looking at the difference between a code and a cipher. A code is a way of representing a larger piece of information by using a smaller word, phrase or, in the case of barcodes and QR Codes, an image.
The spies meeting on the park bench might whisper ‘The eagle has landed’ in which the ‘eagle’ might actually mean the Prime Minister of Uzbekistan and ‘landed’ might be code for ‘arrived at Buckingham Palace for tea with the Queen’.