Matthias,

For what it's worth, I think I may somewhat agree with Jeremy here. The
requirement for any of the fields of the certificate, today, to have any
bearing at all to who possess the key material isn't true, and hasn't been
functionally true for the history of the Web PKI, because we don't really
use Distinguished Names, and that's a Good Thing [1].

In general, we can replace the Subject and Issuer of certificates - for CAs
and end-entity certificates alike - with random values, and still have the
same functional system envisaged by protocols like TLS, and RFCs like the
PKIX series (2459/3280/5280). This is because the system we have is
predicated on machine entity of the end-entity certificate, not
user-visible strings [2], and again, that's a Good Thing.

I understand your desire to identify who is in possession of the Key
Material, but as it stands today, there are no "Know Your CA" rules in the
BRs. The closest you get is Root Program policies, and you can see that
Mozilla's Root Program places that requirement on CCADB. Again, this is a
Good Thing - there's no need for every TLS connection and every certificate
to convey this supplemental information, especially information that
changes. Taken to its logical conclusion, at the point an organization
rebrands, renames, or is acquired, it would need to revoke all of its
extant certificates, to issue new intermediates (notwithstanding new roots
as well), and every site operator replace their certificates. That's not
ideal - and doesn't necessarily further the goal of ubiquitous strong TLS
and security everywhere (... although it might hasten CAs' and site
operators investments in automation, should that become a requirement).

That's not that I disagree with you on the principle of this being silly
rubbish. The notion of branding intermediates is, I think, not necessarily
something that helps us move towards that goal. While I appreciate Jeremy's
point about the useful bookkeeping aspect of that, I'm not sure I agree
that such information needs to be conveyed in every certificate, versus the
use of tools like CCADB, or CAs' own tools (to match issuers to customer
relationships). Indeed, if we were to "redesign" X.509 today, you could
easily imagine replacing or eliminating many fields, and such branding
would, I would hope, be the first to go. To that end, even the CP/CPS (let
alone the userNotice statements) feels a bit excessive, but such is the
world we live in: a world that half embraces the archaic silliness of
X.400/X.500, and half embraces modern, automated, strong validation via
domain names.

To that end, even X.500 is slowly changing; X.501 (10/21) Amendment 1 [3]
finally exploits the CHOICE that is the Name type, allowing the use of DNS
names or opaque values, rather than DNs. While this is not supported by RFC
5280, nor by the common Web PKI implementations, it can be read at least
some as an admission that there are more ways to name things than via a
globally unique directory overseen by the ITU.

That said, I do think you raise some good points, with the way the BRs are
written, today, especially with respect to the definition of CA, and where
such organizations fit. I think that, historically, it's been interpreted
somewhere between the relationship of "management of certificates" (e.g.
can Cloudflare request revocation for those certificates issued to its
customers? AFAICT/AFAIK, "yes") and, in some cases, the entity acting as a
Delegated Third Party of the CA. So although I'm not sure I agree with your
end goal (ensuring things are unambiguously labeled in the cert), I also
think you raise an interesting point worth considering.

[1] https://medium.com/@sleevi_/x-520-whats-in-a-name-da6ea8954b4f
[2] https://datatracker.ietf.org/doc/html/rfc5280#section-2.3
[3] https://www.itu.int/rec/T-REC-X.501-202110-I!Amd1/en

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