Chapter 12: Securing E-mail Messages Using Encryption and Digital Signatures

Overview

Over the course of the last decade or so, no single technology has had as much of an impact on the way people communicate as e-mail. Where once corresponding meant writing or typing out letters to be sent via the postal system, today electronic messages can be exchanged almost instantly - quite literally at the click of a button.

There's no denying that e-mail makes it amazingly simple to keep in touch with friends, family, and business contacts worldwide. However, this convenience comes at a price; e-mail is not a secure communication mechanism by default, and offers nothing in the way of true privacy or confidentiality. Every e-mail message that you send can potentially be intercepted, read, and modified by other users on its journey from the sender to the recipient. Compounding the issue, e-mail offers absolutely no guarantees that a message originated from the person listed as the sender. Others can send e-mail messages pretending to be you or anyone with whom you correspond.

Although the idea that someone else is reading or intercepting your e-mail is a little too "1984" for some people, the reality is that every single unsecured message you send or receive is at risk. Think of every normal e-mail message that you've ever sent or received. Then, ask yourself how comfortable you would feel if a third party was reading or collecting those messages, sending messages in your name, or pretending to be the person you're corresponding with. In the world of unsecured e-mail, each of these scenarios is not only possible, but also very easy to accomplish.

If you've ever used an e-mail client program like Microsoft Windows Mail, you've probably noticed a couple of buttons designed to encrypt and digitally sign messages. In this chapter you learn how secure e-mail systems work, how to configure your Windows Vista system to support secure e-mail, and ultimately how to make use of methods like encryption and digital signatures to secure the contents of e-mail messages and validate the identities of the people with whom you correspond.