IPSec: The New Security Standard for the Internet, Intranets, and Virtual Private Networks, Second Edition

Chapter 1. Cryptographic History and Techniques

Since the beginning of time people have kept secrets. Probably from the beginning of your memory you have done the same. It's a natural human desire. People have always had, and always will have, some secrets that they either want to keep to themselves or share with only a privileged few. The easiest secret to keep is one that you will tell to no one. The more people you wish to share a secret with, and the more public the forum in which you will communicate your secret, the harder it is to keep your secret a secret.

Secrets in History

In antiquity it was easier to keep a secret because the ability to read was a privilege known to a select few. The number of people who could read a written secret was ...