[Smcwg-public] Ballot SMC01: Final Guideline for “S/MIME Baseline Requirements”

Tim Hollebeek tim.hollebeek at digicert.com
Tue Sep 13 14:00:28 UTC 2022

I don’t like the “take precedence” approach, because security properties don’t compose very well.  The requirements should be clear and unambiguous without having to consider once document as having “precedence”.
What we instead want to do, I think, is to clarify the scope of each document in a way so they are non-overlapping.  The most obvious way would be do decided which 3647 sections belong to which document.
There are some spots where that is poorly done today, and it’s causing problems in NetSec.  The logging and retention requirements are the most obvious example.  They’re annoyingly split between the various BRs and NetSec, making them very challenging to update.
The other reason I have a problem with NetSec having precedence is I think of it as more fundamental, with the various BRs being layered on top of it.  Usually, the layered document has precedence to override the parent.  But there’s some value to being able to say “you can’t override this”.  I’ll fail to resist the urge to mention polymorphism, inheritance, and nooverride keywords 😊  Programmers have been struggling with this since they oriented themselves in the direction of objects.
We’ve had similar discussions and problems with the Charters / Bylaws interaction, where the charters should be able to modify some things and not others.  It’s tricky and hard to get right.

From: Smcwg-public <smcwg-public-bounces at cabforum.org> On Behalf Of Corey Bonnell via Smcwg-public
Sent: Tuesday, September 13, 2022 9:41 AM
To: Bruce Morton <bruce.morton at entrust.com>; SMIME Certificate Working Group <smcwg-public at cabforum.org>; Hongquan Yin <Hongquan.Yin at microsoft.com>; Stephen Davidson <Stephen.Davidson at digicert.com>
Subject: Re: [Smcwg-public] Ballot SMC01: Final Guideline for “S/MIME Baseline Requirements”

I agree with Bruce.
The WebTrust SSL Baseline Criteria [1] explicitly reference the NCSSRs as applicable to the operations of CAs regardless of certificate type. In particular, the “Engagement Scoping” section says:
“The Network Security Requirements apply to all CAs within a publicly trusted PKI
hierarchy, even if those certificates are designed for other uses (i.e., code signing, client
authentication, secure email, document signing etc.)”

Given this guidance, I would be rather surprised if there are conflicts. Perhaps one of the WebTrust TF folks here on the list can provide their perspective.

[1] https://www.cpacanada.ca/-/media/site/operational/ep-education-pld/docs/mds21216wtbr-26-rev-august-2022final.pdf?la=en&hash=D96D591D9422E73871B83488D275B9FB78DD1FD7

From: Smcwg-public <smcwg-public-bounces at cabforum.org<mailto:smcwg-public-bounces at cabforum.org>> On Behalf Of Bruce Morton via Smcwg-public
Sent: Tuesday, September 13, 2022 9:28 AM
To: Hongquan Yin <Hongquan.Yin at microsoft.com<mailto:Hongquan.Yin at microsoft.com>>; SMIME Certificate Working Group <smcwg-public at cabforum.org<mailto:smcwg-public at cabforum.org>>; Stephen Davidson <Stephen.Davidson at digicert.com<mailto:Stephen.Davidson at digicert.com>>
Subject: Re: [Smcwg-public] Ballot SMC01: Final Guideline for “S/MIME Baseline Requirements”

Since the NCSSRs apply to TLS, Code Signing and soon to be S/MIME certificates, I would suggest the NCSSRs should take precedence over the certificate documents. I don’t think it would make sense for a CA to be expected to deploy network security differently based on the certificate being issued.
I really think this is a non-issue and the certificate working group should correct any conflicts through ballot.

From: Smcwg-public <smcwg-public-bounces at cabforum.org<mailto:smcwg-public-bounces at cabforum.org>> On Behalf Of Hongquan Yin via Smcwg-public
Sent: Tuesday, September 13, 2022 7:41 AM
To: Stephen Davidson <Stephen.Davidson at digicert.com<mailto:Stephen.Davidson at digicert.com>>; SMIME Certificate Working Group <smcwg-public at cabforum.org<mailto:smcwg-public at cabforum.org>>
Subject: [EXTERNAL] Re: [Smcwg-public] Ballot SMC01: Final Guideline for “S/MIME Baseline Requirements”

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After sharing the guideline to more people in Microsoft, we have some feedback regarding below line:
“6.7 Network security controls
The CA/Browser Forum’s Network and Certificate System Security Requirements are incorporated by reference as if fully set forth herein.”

While the goal of the NCSSR’s is to be certificate agnostic, the history is mostly related to TLS. There’s a risk that a requirement has already been implemented or could be implemented that would conflict with S/MIME requirements. We would recommend adding a statement that if there are any conflicts, that the S/MIME Baseline Requirements take precedence.
Possibly add a sentence such as: “In the event of a conflict between the S/MIME BRs and the NCSSRs, the S/MIME BRs will take precedence.”

Thank you for considering the change.
Hongquan Yin

From: Smcwg-public <smcwg-public-bounces at cabforum.org<mailto:smcwg-public-bounces at cabforum.org>> On Behalf Of Stephen Davidson via Smcwg-public
Sent: Thursday, September 8, 2022 3:03 PM
To: smcwg-public at cabforum.org<mailto:smcwg-public at cabforum.org>
Subject: [EXTERNAL] [Smcwg-public] Ballot SMC01: Final Guideline for “S/MIME Baseline Requirements”

Ballot SMC01: Final Guideline for “S/MIME Baseline Requirements”

Purpose of Ballot:

The S/MIME Certificate Working Group was chartered to discuss, adopt, and maintain policies, frameworks, and standards for the issuance and management of Publicly-Trusted S/MIME Certificates.  This ballot adopts a new “S/MIME Baseline Requirements” that includes requirements for verification of control over email addresses, identity validation for natural persons and legal entities, key management and certificate lifecycle, certificate profiles for S/MIME Certificates and Issuing CA Certificates, as well as CA operational and audit practices.

An S/MIME Certificate for the purposes of this document can be identified by the existence of an Extended Key Usage (EKU) for id-kp-emailProtection (OID: and the inclusion of a rfc822Name or an otherName of type id-on-SmtpUTF8Mailbox in the subjectAltName extension in the Certificate.

The following motion has been proposed by Stephen Davidson of DigiCert and endorsed by Martijn Katerbarg of Sectigo and ­­­Ben Wilson of Mozilla.

Charter Voting References

Section 5.1 (“Voting Structure”)<https://urldefense.com/v3/__https:/nam06.safelinks.protection.outlook.com/?url=https*3A*2F*2Fgithub.com*2Fcabforum*2Fservercert*2Fblob*2Fe6ad111f4477010cbff409cd939c5ac1c7c85ccc*2Fdocs*2FSMCWG-charter.md*2351-voting-structure&data=05*7C01*7Chongquan.yin*40microsoft.com*7C70f13519b92c4417b4f508da91682f2b*7C72f988bf86f141af91ab2d7cd011db47*7C1*7C0*7C637982174108537999*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C3000*7C*7C*7C&sdata=HhWwlEUw7uF2tm*2Fzit*2BBZmgz7*2Bp0jct*2BHpHkEe5BDuQ*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJSUlJSUlJSUl!!FJ-Y8qCqXTj2!bWnvHPfCC3lJ-KbHci51bKRgKlhjdnc9268DFF06vf4uwVnm02oCOBMe-etaI9xO36KbTeDwFmakK0z976n3T_UkEPs0$> of the SMCWG Charter says:

In order for a ballot to be adopted by the SMCWG, two-thirds or more of the votes cast by the Certificate Issuers must be in favor of the ballot and more than 50% of the votes cast by the Certificate Consumers must be in favor of the ballot. At least one member of each class must vote in favor of a ballot for it to be adopted. Quorum is the average number of Member organizations (cumulative, regardless of Class) that have participated in the previous three (3) SMCWG Meetings or Teleconferences (not counting subcommittee meetings thereof).


This ballot adopts the “Baseline Requirements for the Issuance and Management of Publicly-Trusted S/MIME Certificates” (“S/MIME Baseline Requirements”) as Version 1.0.0.

The proposed S/MIME Baseline Requirements may be found at https://github.com/cabforum/smime/compare/7b3ab3c55dd92052a8dc0d4f85a2ac26269c222e...28c0b904fe54f1c5f6c71d18c4786a3e02c76f52<https://urldefense.com/v3/__https:/nam06.safelinks.protection.outlook.com/?url=https*3A*2F*2Fgithub.com*2Fcabforum*2Fsmime*2Fcompare*2F7b3ab3c55dd92052a8dc0d4f85a2ac26269c222e...28c0b904fe54f1c5f6c71d18c4786a3e02c76f52&data=05*7C01*7Chongquan.yin*40microsoft.com*7C70f13519b92c4417b4f508da91682f2b*7C72f988bf86f141af91ab2d7cd011db47*7C1*7C0*7C637982174108694198*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C3000*7C*7C*7C&sdata=LeGxSesCeeTKziMM1pTk985zVUXqAwvzuEWlVJJ6OyQ*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJSU!!FJ-Y8qCqXTj2!bWnvHPfCC3lJ-KbHci51bKRgKlhjdnc9268DFF06vf4uwVnm02oCOBMe-etaI9xO36KbTeDwFmakK0z976n3T_BUsJam$> or the attached document.

The SMCWG Chair or Vice-Chair is permitted to update the Relevant Dates and Version Number of the S/MIME Baseline Requirements to reflect final dates.


This ballot proposes a Final Guideline. The procedure for approval of this ballot is as follows:

Discussion (7+ days)
Start Time: 8 September 2022 17:00 UTC
End Time: 15 September 2022 17:00 UTC

Vote for approval (7 days)
Start Time: 15 September 2022 17:00 UTC
End Time: 22 September 2022 17:00 UTC

IPR Review (60 days)
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