PGP, or Pretty Good Privacy, is a security program that allows users to encrypt and decrypt e-mail, as well as incorporating the added protection of digital signatures for user verification. OpenPGP builds upon PGP with enhanced PGP standards, military-grade security and an increased number of encryption algorithms.
Chapter 8 -- "OpenPGP and Email" -- of PGP & GPG: Email for the Practical Paranoid explains how to encode messages and describes the different types of email encryption keys available to users.
Excerpted from PGP & GPG: Email for the Practical Paranoid, First edition by Michael W. Lucas (ISBN: 1-59327-071-2). Copyright © April 2006 No Starch Press, Inc. All rights reserved.