[cabfpub] Ballot 188 - Clarify use of term "CA" in Baseline Requirements

Ryan Sleevi sleevi at google.com
Mon Feb 27 19:21:19 UTC 2017

On Mon, Feb 27, 2017 at 10:52 AM, Dimitris Zacharopoulos <jimmy at it.auth.gr>

> I think this is a potentially problematic definition, in that it relates
> to the scope of the operations of the audit, as well as matters below that
> I highlight. I'm hoping the proposers and drafters can clarify (or link to
> previous discussions) as to the reason in which "or its Affiliate" was
> introduced into these definitions, or to highlight where it was already a
> natural and existing part of these definitions.
> Peter already provided some clarity for this. The "Affiliate" language was
> not introduced by this ballot. It was already mentioned in several sections
> of the BRs ( "CA Key Pair Generation", 6.1.2 "Private Key Delivery
> to Subscriber", 6.2.6 "Private Key Transfer into or from a Cryptographic
> Module", "Subordinate CA Certificate" and "Subordinate CA
> Certificates").

Unfortunately, I think the concern still remains that this is a subtle
introduction that goes from being scoped to specific sections (as you've
noted) to now being a foundational concept, which unfortunately 'weakens'
the BRs, I believe.

I totally understand and appreciate the intent to align here, especially
for the cases Peter noted, but I want to especially make sure to highlight
the issue that "or the Affiliate" can be problematic from a set of scope of

Basically, what's being asked for on this ballot is a trade-off from being
logically bugged (and I agree, this is an issue we should fix) to something
that is procedurally weaker, and I'm trying to figure out what the plan is
to align. From both you and Peter's response, it sounds like you don't
believe further changes are needed, and this is concerning.

> Peter's answer should cover this. Your follow-up questions challenge the
> fact that the current BRs treat Root Operator's "Affiliates" in a different
> way than the non-Affiliates but this is a policy matter and should be
> discussed separately. In any case, I don't think it changes the fact that
> all Subordinate CAs (whether internally or externally operated) need to be
> audited. In the case of Internally Operated Subordinate CAs, the audit
> might be covered in the Root Operator audit, and this information should be
> included in the audit scope.

That's the intent - but my question is, where is it specified? I may have
missed that, and that was the point of raising these concerns: if I'm
misreading, and it's already addressed, fantastic. But I don't believe it
is, hence the concern :)

> After several discussions within the WG, it was agreed that the most
> accurate technical language is that "Private Keys sign Certificates".
> Certificates, don't sign Certificates.

I understand the "why". I'm more specifically asking three questions:
1) Is my interpretation correct?
2) Is this desired?
3) Is there a plan to fix it?

>From the rest of this section, I can interpret your response as "1) Yes 2)
No, not necessarily 3) Not really, but we could come up with one". I'm not
sure if that really provides the level of assurance when considering
whether to vote on this ballot, even though I agree and understand the why,
and am relieved it isn't intended.

> So, according to your example, if the ResponderID was the hash of the
> Subordinate CA Certificate's public key, it would not be prohibited even
> though that key would be included in two or more Subordinate CA
> Certificates. Perhaps the multiple CA Certificates with the same key-pair
> scenario is not entirely addressed. We could update the BRs to specifically
> include language for the ResponderID information, if you think people would
> be puzzled about what information should be included in that field.

Whether we address this by specifying language fro the ResponderID (which
seems overly specific) or by addressing the general concern, I'd like to
see a concrete proposal to address this, ideally before voting concludes.

> In Section 4.9.10 (On-line revocation checking requirements)
> Was this intentional?
> This specific change was addressed during the discussion phase (
> https://www.mail-archive.com/public@cabforum.org/msg02652.html).

Did you link to the right thread? I cannot find a clear answer, but perhaps
I'm just missing it. As it stands, I think this alone is potentially
grounds that we may need to vote against it, because it's a clear reduction
in assurance.

> A typo indeed. It is clear in the red-lined version.

For future reference, we should try to figure out what version is being
voted on, when the e-mailed ballot and Red Line disagree :) This is a minor
issue, but I can easily see more significant issues creeping in, least of
all, because I have not looked at all at the Red Lined version, because
that's not the balloted text :)

> In Section 8.7 (Self-Audits)
>> Replace the last paragraph with:
>> During the period in which a Technically Constrained Externally Operated
>> Subordinate CA issues Certificates, the Issuing CA SHALL monitor adherence
>> to the Issuing CA's Certificate Policy and/or Certification Practice
>> Statement and the Externally Operated Subordinate CA's Certificate Policy
>> and/or Certification Practice Statement. On at least a quarterly basis,
>> against a randomly selected sample of the greater of one certificate or at
>> least three percent of the Certificates issued by the Externally Operated
>> Subordinate CA, during the period commencing immediately after the previous
>> audit sample was taken, the CA SHALL ensure adherence to all applicable
>> Certificate Policies and/or Certification Practice Statements.
> Much like several other changes mentioned above, this limits the scope of
> the existing text from "internal or external" to simply "external". Thus it
> reduces the scope of examination for internally operated subordinate CA
> certificates, which may be operated by an Afilliate under a distinct
> CP/CPS. Is that fair to say?
> The rest of the section remains the same. It doesn't remove the obligation
> for the CA (this covers ALL CA organizations, including affiliates) to
> perform quarterly self-audits.
> The reasoning for changing the last paragraph to only "Externally Operated
> Subordinate CAs", was that the language dictates that the "Issuing CA SHALL
> monitor adherence...". We thought that it doesn't make sense to have one
> organization monitor adherence to it's own organization. It is already
> required for the Root CA Operator to adhere to its own CP and/or CPS (that
> must cover all Internally Operated Subordinate CAs), check against a
> randomly selected sample, etc, as specified in the first paragraph of
> section 8.7.

So I think the point you're making is important, and I'm not cleared where
it's technically spelled out or required, and do hope you can highlight

You're asserting that all Internally Operated Subordinate CAs are operated
by the Root Operator AND, if I'm understanding correctly, audited to the
same CP/CPS as the Root CA Certificate - is this correct?

I haven't found text to normatively require either statement, and that's
the concern: even if it's the same organization as the Root Operator, the
possibility for distinct CP/CPSes to exist between the Root CA
Certificate's policies and the Internally Operated Subordinate CA's
policies (and/or independent audits) exists, and as much as possible, I
want to ensure the same consistent duty of care with respect to policies
and practices. I fear this introduces a loophole for Affiliates to 'skip'
audits and key protection, even if unintended, so I'm curious if we can
find a resolution for this within the voting period.

> Here are the two definitions introduced:
> *Root CA Operator:*  The top-level Certification Authority (i.e. an
> organization) whose CA Certificate (or associated Public Key) is
> distributed by Application Software Suppliers as a trust anchor
> *Internally Operated Subordinate CA:*  A Subordinate CA Operator,
> operated by a Root CA Operator or its Affiliate that is in possession or
> control of the Private Key associated with the Subordinate CA Certificate
> The Root CA Operator is already -by definition- responsible for all
> actions related to its Internally Operated Subordinate CAs and Affiliates.

I disagree, and that's the point of concern. If the Root CA Operator
included the definition of Affiliates - ergo bringing consistency to the
scope of audits and operation - then perhaps this issue would be resolved
(of course, it may introduce new bugs). But as it stands, an Internally
Operated Sub CA having the "or its Affiliate" creates a loophole in which
all the policies which apply to a Root CA Operator _don't_ apply to the
Affiliate, because IOSCAs clearly distinguish Affiliate as "something other
than the Root CA Operator"

Does this make sense?

> Voting ends on Thursday March 2 at 22:00 UTC but the remaining issues will
> be tracked and addressed in a future ballot.

My hope is something a bit more concrete than future ballot before then,
because I think some of these concerns are enough to prevent our support
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