Bletchley Juniors Codebreaking Club opened its doors today for its first intake of codebreakers. I started with some steganography, explaining that it is an Ancient Greek word meaning “covered writing”. I asked for a volunteer. Every child put their hand up. I said it was lovely that they were all so keen, but they did not know what they were volunteering for! I then chose one child and asked them to come to the front. I explained that they had to act the part of a slave in Ancient Greece. They looked a bit doubtful, but gamefully carried on. I played the part of Histiaeus, and Anna played the part of Aristogoras, his son in law, who lived in different parts of Greece. We role-played me shaving the slave’s head and tattooing a message on their head. We then waited several weeks for the hair to grow back. I then gave the slave their instructions (they had to memorise a line) and sent them on their way to Aristogoras. When they arrived they said “shave my head and look thereon”. Aristogoras did this and read the message. The slave then had to wait for their hair to grow back again before they could travel home. I wanted to start with something quite light-hearted but which would also get the children thinking about the different stages to sending a message.
I then showed the children a scytale, a tool used by the Ancient Greeks to communicate during military campaigns.
I showed them one I made earlier. I unwound the paper to show that when you try to read down, the message makes no sense. I demonstrated that the person receiving the message must have a scytale of the same diameter, or the message cannot be read.
The children then had a go at making their own scytale using cardboard tubes and long strips of paper. They first had to plan and write their message on separate paper, to make sure it was the correct length. The wound their strip of paper around the tube, attached it with tape and wrote their message on it, putting one letter on each strip. They unwound their message and swapped it with another child, then tried to read and write down the new message. The children seemed to really enjoy the opportunity to use their hands and make something. We gave them spare strips of paper to take home if they wanted to, along with the tubes.
We ended by giving out log books I had made (and hand-stitched!). I asked the children to write in steganography and scytale as our two topics from the session.