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.

The draft is clear and well-written. The Security Considerations section specifically is comprehensive and clear.

My one suggestion would be to move the first paragraph in the Security Considerations section to the Introduction. It is about the attack and about the protocol in the document being effective against the attack. It's not really a consideration in the way that the rest of the section is.