[Smcwg-public] Bridge CA

[Wendy Brown - QT3LB-C]

at least change the definition to
Bridge CA – A CA that facilitates interoperability between different
enterprises or communities that operate their own PKIs, through the use of
Cross Certificates with participating CAs.

Because your wording perpetuates the misunderstanding that Bridges are used
as the Root for their community, which is not the case.  Most Bridges do
not make their self-signed certificate available to be used as a trust
anchor.

Although Judy may not agree with me, I would even prefer leaving out all
mention of Bridge CAs in the document and instead just make it clear that
the document is only applicable to PKIs that adopt them by asserting any of
the CAB Forum certificate policy OIDs in certificates they issue and are
included in one or more of the public trust programs managed by the member
certificate consumers.

I agree with the first sentence of your closing paragraph:

Bridge CAs fall outside of mandatory adoption of the SBR unless the Bridge
CA itself is Publicly-Trusted.

However, the last sentence is again misleading

If a CA that is crossed with the Bridge CA is itself Publicly-Trusted then
it must adopt but it does not drag other nonPublicly-Trusted CAs in the
Bridge ecosystem into scope.

That is exactly the issue that was created that resulted in the
Symantec issue a number of years ago. Because there was a Symantec Root in
the public trust stores that had issued a cross-certificate to the FBCA,
people felt that Symantec was therefore responsible for all of the PKIs in
the FPKI following all the BRs when in fact many of them did not even issue
TLS certificates and would not have created valid paths to that root if the
browsers had correctly done certificate policy processing during path
validation according to RFC 5280.

Bridges are NOT the root of trust for their community, instead they operate
more as a hub, allowing peer PKIs to only have to issue 1 cross-certificate
to the Bridge, while the Bridge issues cross-certificates to all the member
peer PKIs.  This allows each member PKI to use their own Root as a Trust
Anchor while enabling them to trust all the other member PKIs.  Essentially
the Bridge is an intermediate CA between each pair of peer PKIs in the
community.

Thanks, (and sorry to be providing what may seem to be too many details for
the current discussion)

Wendy


Wendy Brown

Supporting GSA

FPKIMA Technical Liaison

Protiviti Government Services
703-965-2990 (cell)


On Wed, Aug 3, 2022 at 6:10 PM Stephen Davidson <
Stephen.Davidson at digicert.com> wrote:

> Hi Wendy – thank you for the suggestion.
>
>
>
> I’d like to stick with the original simpler text because the SBR doesn’t
> address “how a Bridge CA operates” apart from adopting some CABF-wide
> standards covering Cross Certificate profiles.
>
>
>
> Bridge CAs fall outside of mandatory adoption of the SBR unless the Bridge
> CA itself is Publicly-Trusted.  If a CA that is crossed with the Bridge CA
> is itself Publicly-Trusted then it must adopt but it does not drag other
> nonPublicly-Trusted CAs in the Bridge ecosystem into scope.
>
>
>
> Best, Stephen
>
>
>
>
>
> *From:* Wendy Brown - QT3LB-C <wendy.brown at gsa.gov>
> *Sent:* Wednesday, August 3, 2022 3:00 PM
> *To:* Stephen Davidson <Stephen.Davidson at digicert.com>; SMIME Certificate
> Working Group <smcwg-public at cabforum.org>
> *Subject:* Re: [Smcwg-public] Bridge CA
>
>
>
> Stephen - suggested rewording of the Bridge CA definition
>
>
>
> Bridge CA – A CA that facilitates interoperability between different
> enterprises or communities that operate their own PKIs, by issuing and
> receiving Cross Certificates which map the peer PKI certificate policies to
> the certificate policies of the Bridge CP.
>
>
>
>
> Wendy
>
>
>
> Wendy Brown
>
> Supporting GSA
>
> FPKIMA Technical Liaison
>
> Protiviti Government Services
>
> 703-965-2990 (cell)
>
>
>
>
>
> On Wed, Aug 3, 2022 at 12:39 PM Stephen Davidson via Smcwg-public <
> smcwg-public at cabforum.org> wrote:
>
> Hello:
>
>
>
> Following our discussion, I have merged the PR relating to Bridge CAs
> https://github.com/cabforum/smime/commit/50093055e1a2db9822cc68f90f503b48210f576a
>
>
>
> As discussed we will want to add a definition for a Bridge CA.  I propose
> the following:
>
>
>
> Bridge CA – A CA that facilitates interoperability between different
> enterprises or communities that operate their own PKIs, by issuing Cross
> Certificates to participating CAs.
>
>
>
> Feedback welcomed.
>
>
>
> Regards, Stephen
>
>
>
> _______________________________________________
> Smcwg-public mailing list
> Smcwg-public at cabforum.org
> https://lists.cabforum.org/mailman/listinfo/smcwg-public
>
>
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