I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. This document defines an extension to CMS that gives content constraints. It does this in an admittedly-limited way, not trying to deal with all types of constraints or all types of content. This extension is certainly security-related, affecting the CMS processing rules, but only for CMS implementations that know about the extension. The Security Considerations section lists some significant implementation choices made by the authors that could trip up an implementer, but these are also called out reasonably well in the body of the document as well. --Paul Hoffman, Director --VPN Consortium