Introductory level overview of digital certificates.

Introduction to the practical aspects of conventional and public-key cryptography. (PDF and Postscript sample chapters)

Encyclopedia article about the ITU-T standard for a public key infrastructure. Includes history, certificate details, and references.

Document by Peter Gutmann intended as a set of implementation notes and guidelines for developers.

Provides guidance and recommendations to developers building X.509 public-key certification paths within their applications.

Official web pages containing the standards published by the International Telecommunication Union.