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 has some minor issues. 

Security considerations - in addition to Jari's comment of lifetime may be sensitive I have concerns about linked resource.  For example, the link may refer to another site which could compromise privacy or security if the link was followed.  The linked resource seems under-defined, which might lead to security issues if implementations make assumptions about the content of the link.