Public key encryption solves that problem. This means that someone who uses public key encryption can give her public key to anyone and everyone, confident that her encoded messages are safe. Many people don't know that e-mail messages are sent over the Internet without any scrambling whatsoever. It doesn't take much effort for a curious hacker to read the data sent along the net, including the entire text of your e-mail. Imagine if all postal mail had to be sent using postcards.
Encryption provides an envelope for e-mail.
Even if most of the e-mail messages we send are perfectly innocent, we wouldn't necessarily be happy if everyone read them. This essay really only touches the surface of what can be done with encryption. Download PGP and give it a try. Any encrypted e-mail sent to me using my public key will get an immediate reply. Jamais Cascio is a consultant and writer specializing in scenarios of how we may live over the next century.