Subject: [Acme] Benjamin Kaduk's Yes on draft-ietf-acme-email-smime-13: (with COMMENT)

From: Benjamin Kaduk via Datatracker <[email-masked]>
Date: Wed, 13 Jan 2021 15:04:04 -0800

Benjamin Kaduk has entered the following ballot position for
draft-ietf-acme-email-smime-13: Yes

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COMMENT:
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Thanks for the updates to get to the -13; they look really good.

The new text did inspire one further comment, though I don't see a
particular text change that might result, plus I spotted a few editorial nits.

Section 1

   1.  A Mail User Agent (MUA) which has built in ACME client aware of
       the extension described in this document.  (We will call such
       ACME clients "ACME-email-aware") Such MUA can present nice User
       Interface to the user and automate certificate issuance.

(nit?) In the parenthetical, are we calling the ACME clients or the MUA
"ACME-email-aware"?  Also, full stop for the end of the sentence.

Section 3

(nit?) In step 8, the MUST-level requirement in the last sentence probably
promotes it into not being a parenthetical.

Section 3.1

          If S/MIME signing is used, the certificate corresponding to
          the signer MUST have rfc822Name subjectAltName extension with
          the value equal to the From header field email address of the
          "challenge" email.

A strict equality requirement might make it operationally challenging to
use a unique "from" challenge for each request.  I don't see any
feasible alternative, though, as getting into + suffixes in the local
part seems like a non-starter for this document.

Also, nit: s/subjectAltName extension/a subjectAltName extension/