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. I have previously reviewed version -14 of this document and have now went through version -19. I find that the document has significantly improved in quality and I would like to thank Mark for addressing my comments.