It's high-time people started using e-mail encryption. Even though you may be using a web-based e-mail account with that little lock that says you're using a safe connection (like GMail), there's no guarantee that after that e-mail leaves your computer, it won't be transmitted in plain text across the Internets before reaching your recipient's eyes.

Enter Public-Key encryption. While the math is rather complicated, the concept's rather simple: you have two keys and one lock box. One key opens the lock and the other one closes the lock. (There is no key that can both open and close that lock.)

When someone wants to send you something securely, they take your lock box, use the key that closes the box, and then sends the securely-closed box to you knowing you're the only one who has the key to open it. Likewise, if you want to send something securely back, you take their lock box and use their key to lock something inside the box, knowing only they have the key to open it.

The key that closes these lock boxes is called "public key" because it doesn't matter who has it. Only the "private key" can open it; whoever owns the private key, owns the message...presumptively.

So you may send me secure e-mails, I've included my Public Key for your use.

If you need help setting up e-mail encryption, try here: Wolfram's GPG How-To. I use WinPT.

For those daring enough, you can get this to work through GMail as well.