12 years+: Ciphers

Make up your own ciphers (coding systems) to write and translate secret messages.

Here are some cipher ideas to get you started.

Number coding is an easy way to create coded messages is by substituting numbers for letters,

e.g. A = 1, B = 2, C = 3 and so on...

Book ciphers require both the coder (person writing the coded message) and the decoder (the person deciphering it) to have a copy of the same book. Provide the book title, page number, line number and word number to identify each individual word in your secret message.

This ancient coding system requires a long strip of paper and a cylinder (cardboard tube or rolling pin). Start by wrapping the paper around the cylinder. Hold it in place whilst you write your message along the cylinder. When unwrapped, the message will be nonsense and the decoder will have to use a cylinder of the same size to re-wrap the paper and understand the message.