Security review of CAA Record Extensions for Account URI and ACME Method Binding draft-ietf-acme-caa-06 Do not be alarmed. 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 of this document is DNS records describing certificate issuance policies and how the policies can be made more granular through the use of two new parameters: accounturi and validationmethods. The first parameters designates particular accounts that can act as CAs for a domain, the second parameter names the methods that can be used for validation. It took me almost an hour to realize that "accounturi" was "account uri". It looked like some fancy foreign word. "He was not merely an accountant, he was an acounturi from a noble hereditary line." Moving on, the document claims that the only effect of the new parameters is to narrow the ways in which a certificate should be issued. There are no additional security measures. Bad actors can still be bad, men can remain in the middle. The new parameters are there for the use of good actors. I am not convinced that all of the items in section 5 really are "security considerations". The increased granularity is not in itself a security meaure. Some of the items relating to validation methods and DNSSEC are security consideration. As nearly as I can tell, there are no security problems. Hilarie