I 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 authors, document editors, and WG chairs should treat these comments just like any other IETF Last Call comments. Document: draft-ietf-acme-star-delegation-06 Reviewer: Russ Housley Review Date: 2021-03-14 IETF LC End Date: 2021-03-22 IESG Telechat date: unknown Summary: Not Ready Major Concerns: Abstract: It says: "... party access to a certificate associated with said identifier." This is odd wording, and it is incorrect. The party needs access to the private key that corresponds to the public key in the certificate, and the certificate needs to contain the subject for "said identifier". Clearly, all of that should not go in the Abstract, but what does appear in the Abstract needs to be technically accurate. Section 1 says: "... name matches the authority ...". I find this description confusing. I think it would be more clear to say that the cache server needs to present a certificate whose subject name matches the domain name of the URL that is requested. The current wording is very easy to confuse name of the Certification Authority. Section 1 says: While the primary use case we address is delegation of STAR certificates, the mechanism proposed here accommodates any certificate managed with the ACME protocol. See Section 2.4 for details. This is not much of a hint that long-term certificates are supported in addition to STAR certificates. Further, a hint about the handling of revocation is appropriate here. Support for long-lived certificates is in conflict with the title of the document. Please adjust the title of the document accordingly. Section 2.3.2 says: "Besides, when delegation is for a STAR certificate, ..." (in four places in this section). I find this part of the document structure a bit confusing. Maybe it is the lask ot adequate warning about support for long-lived certificates. Maybe it the the mixing of STAR certificate and long-lived certificate processing in one section. I suggest that separate sections be used to present STAR certificate and long-lived certificate processing In Section 2.3.4, the text is begging for one more sentence. Please say something about the fact that the STAR certificate will expire shortly after the automatic renewal process is stopped by the IdO. Section 2.4 is not sufficient to explain the revocation processing. Only the NDC has the private key needed to make the ACME revocation request, but this does not get stated in the text. Also, it is not clear to me how the NDC knows where to send the revocation request since the IdO is the ACME account owner. In addition, the phrase "would create a self-inflicted DoS" needs more explanation. Section 5.6 registers a string name for each extendedKeyUsage OID. There should be a way to provide the OID in dotted decimal format as well. New OIDs are being assigned all the time, and some of them may not be registered with IANA. Section 5.6 registers a string name for each type of subjectAltName. This include otherName, which are identified by an OID. New OIDs are being assigned all the time. For example, draft-ietf-anima-autonomic- control-plane-30 creates a new otherName. There should be a way to provide the the otherName OID in dotted decimal format as well. Minor Concerns: Abstract: Please spell out ACME, CDN, and STAR. These are not marked as "well known" in the RFC Editor abbreviation expansion list. Section 1 describes [I-D.mglt-lurk-tls13] as an ongoing effort. This is not accurate. The LURK BoF did not lead to a WG or an effort in an existing WG. I think the best way forward is to drop this reference. Section 1.1: Please change CA to "Certification Authority". See Section 3 of RFC 5280. This changes is also needed elsewhere in the document. Section 1.1: Please add CDNI, uCDN, dCDN, PASSPorT, CSR and FQDN to the list of terms. Nits: Section 2 says: "... in this draft ...". Please use a work that will still be appropriate when this document becomes an RFC. Section 2.4: s/Sec. 7.6/Section 7.6/ (and many other places) IDnits reports: ** There are 3 instances of too long lines in the document, the longest one being 4 characters in excess of 72. == There are 4 instances of lines with non-RFC6890-compliant IPv4 addresses in the document. If these are example addresses, they should be changed. [I suspect these are not IPv4 addresses, but OIDs in dotted decimal.]