What is Cryptography?

Cryptography is the study or art of writing and sending secret messages using codes.

“Enigma Crypto Machine” by Latente 囧 is licensed under CC BY-SA 2.0

Types of Cryptography

Semaphore – Used by the military to send messages between ships and across battlefields. Each letter of the alphabet has it’s own flag movement (British Pathe)

Morse code – Using light of sound to send messages. Morse can be used in an emergency to indicate that you are in trouble. SOS or dot dot dot/dash dash dash/dot dot dot can be signalled with a mirror of torch.

Morse code translator is a great way to discover changing text into light and sound versions of Morse code. Why not have a go at making some Morse code messages. Open the link below and add a text sentence to the input field. Press play. Not only will the translator change the text into dots and dashes but it will also play the sounds. Now select the Light button on the console and the message will play both in sound and in light.

Caesar cypher – The emperor Julius Caesar sent secret messages using a shift cypher. He moved the letters along in the alphabet to represent a code. (Khan Academy) – dcode has a fantastic range of free conversation tools to illustrate Caesar ciphers, binary code and other interesting code formats, such as using the German enigma code used in World War 2. (There are some adverts on the pages and you can donate to keep the pages free if you want to. Children should always ask parents before doing this).