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 subject matter is outside my area of expertise but addressing the obvious attack vector related to authenticated purge messages seems like a good catch. The document is well written and clearly describes what registries and documents are updated.