CertiGuide to Security+  9  Chapter 4:  Basics of Cryptography (Domain 4.0; 15%)       9  4.4  Standards and Protocols

IEEE 1 IETF

The ANSI X.509 digital certificate standard grew out of discussions in the late 1980’s. Augmented by further work on the Privacy Enhanced Mail (PEM) standard in the early 1990’s, X.509v3 is the current industry standard for digital certificate formats. The second version of X.509 added serial numbers to uniquely certificate authority and the subscriber. The latest version of this standard, X.509 version 3, adds extended attribute fields so that certificates can convey additional information such as security clearance level.

X.509 also includes standards for certificate revocation, with the current version of the CRL standard being X.509v2. Version 2 of the CRL standard allows for extensions (like the V3 certificate), standard extensions such as reason code/suspension/etc., CRL distribution points (improves scalability for large CRL’s by allowing multiple sites to distribute portions of the list), and a “Delta CRL” containing only the incremental changes in the CRL.

IEEE 1 IETF