Codes

Before we learn about Computer Code we will learn how secret messages can be encoded and decoded. This has been done for hundreds of years. The Freemasons used the Pigpen Cipher.

A cipher is a way of writing a secret message by changing or rearranging the letters in a message. So, the pigpen is a cipher because it changes the letters into symbols. These letters correspond to the position on a grid. Both the sender and the receiver must understand the system to decrypt the cipher.

We don’t use a codebook with a cipher. Instead, we follow a series of instructions (also known as algorithm). It often involves the use of a shared key.