RFC 4262 · PROPOSED STANDARD · 2005

X.509 Certificate Extension for Secure/Multipurpose Internet Mail Extensions Capabilities

Overview

RFC 4262, “X.509 Certificate Extension for Secure/Multipurpose Internet Mail Extensions Capabilities”, is a Proposed Standard document published in December 2005 by S. Santesson. The canonical text is published by the RFC Editor.

Abstract

This document defines a certificate extension for inclusion of Secure/Multipurpose Internet Mail Extensions (S/MIME) Capabilities in X.509 public key certificates, as defined by RFC 3280. This certificate extension provides an optional method to indicate the cryptographic capabilities of an entity as a complement to the S/MIME Capabilities signed attribute in S/MIME messages according to RFC 3851. [STANDARDS-TRACK]

Abstract as published in the RFC, via rfc-editor.org.

What “Proposed Standard” means

An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.

Read this RFC

The canonical text of RFC 4262 is hosted at rfc-editor.org. Available in TXT,HTML.

Other RFCs from 2005

Who Is Online

In total there are 81 users online: 0 registered, 74 guests and 7 bots.

Most users ever online was 5,555 on 17 Jul 2026, 3:23 am.

Bots: Applebot Baiduspider Bingbot Other Bot Other Spider PetalBot SemrushBot

Users active in the past 15 minutes. Total registered members: 372