When the first edition of this book was published in 1996, many people believed that a working public key infrastructure was a prerequisite for commerce on the World Wide Web. We disagreed. At that time, there was already substantial commerce occurring on the Internet based on old-style, easily forged credit cards, rather than high-tech digital signatures. We argued that the additional security offered by digital signatures might not be necessary if there was money to be made.
Today, the need for a widespread PKI is even more compelling, yet it seems more remote than ever. There are growing incidents of fraud on the Internet, and there is an increasing need to use digital signatures to do business. Yet despite the passage of digital signature legislation in the United States that makes a digital signature as legally binding as a written signature, widespread PKI seems further away today than it was in 1996.
It is not clear that the current vision of a public key infrastructure can even be built. Today’s vision calls for a system with multiple CAs and with thousands or millions of different users, each obtaining, invalidating, and discarding certificates and public keys as needed. For the past 30 years, this type of technology has really not been tested outside the lab except in very controlled environments.
In the following sections, we’ll look at a few of the problems that must be faced in building a true PKI.
Digital signatures facilitate ...