Computer and Information Security Handbook

Chapter 26

Public Key Infrastructure

Terence Spies, Voltage Security, Inc.

The ability to create, manipulate, and share digital documents has created a host of new applications (email, word processing, ecommerce Web sites), but it also created a new set of problems—namely how to protect the privacy and integrity of digital documents when they’re stored and transmitted. The invention of public key cryptography in the 1970s¹—most important, the ability to encrypt data without a shared key and the ability to “sign” data, ensuring its origin and integrity—pointed the way to a solution to those problems. Though these operations are quite conceptually simple, they both rely on the ability to bind a public key (which is typically a large mathematical ...