Privacy is a big concern these days on the internet. How do we share our information without having it fall into the wrong hands?
Middle and Older Kids spent a couple classes learning a bit about cryptography, the science of encoding information to keep it secret. We started with simple letter-substitution ciphers, like the Caesar Cipher, and played games and decoded jokes on Cryptoclub.org.
Of course, something like a simple cipher won't stop the bad guys for long. We discussed public-key cryptography, a kind of one-way encryption, so that anybody can encrypt a message, but only the recipient can decode it. That's the most common kind of encryption used on the internet today.