Instructables has just posted the latest installment in their series of HOWTOs inspired by my young adult novel Little Brother (remember, you can get on BBtv with your own videos demonstrating these).
Today, the subject is using encrypting your Gmail messages:
The principle behind GPG encryption is easy. Anyone who wants to play creates a public key and a private key. Your public key is the part of the encryption that you make public. Your private key is the part of the encryption that you never share with anyone under any circumstance.The two keys work together so that you need both to decrypt anything. To send an encrypted message to someone you lock the message with their public key and when they get it, they can unlock it with their private key. If they want to respond, then they encode the message with your public key and you can read it with your private key.
Of course, this only works so long as you can trust that you have been given the right public key and that you know who you are talking to. One of doing this is by having a key signing party with your close friends. You all show up at a given location at a given time and exchange public keys. Then you have a list of trusted public keys with which you can communicate. This is often referred to as a web of trust.
