Hi all, I'll reiterate my previous position: Policies are set by the PKI in which the CA operates; practices are described by the CA. Having each CA write its own CP has always been a category error. CP documents are *prescriptive*, and rely extensively on RFC 2119 keywords. CPS documents are *descriptive*, and should contain zero uses of the RFC 2119 keywords.
In my opinion, a combined CP/CPS should be nearly identical to a standalone CPS, and contain no uses of RFC 2119 keywords. The CP portion of a combined document is just the paragraph at the top stating conformance to the Baseline Requirements (as required by BRs Section 2.2 <https://github.com/cabforum/servercert/blob/main/docs/BR.md#22-publication-of-information>) and other root program policies (as required by the Chrome Root Program Policy Section 1.1.3 <https://googlechrome.github.io/chromerootprogram/#113-chrome-root-program-participant-policies>, among others). With that context, my responses to Ben's specific questions are inline: On Sun, Aug 9, 2026 at 11:11 AM 'Ben Wilson' via [email protected] <[email protected]> wrote: > Does a CPS statement commit a CA to a practice even if it does not use > words such as MUST, each, or every? > It is my opinion that a CPS or combined CP/CPS statement* definitely does* commit a CA to a practice even when the statement does not use MUST / SHALL / etc. Other words like "each" or "every" are more ambiguous. That gets into your other questions about ordinary meaning, drafter's intent, and genuinely unclear statements. > What should be Mozilla's process or criteria when a CPS provision is > identified as ambiguous or unclear? (E.g. ordinary meaning, the > surrounding text, certificate profiles, applicable requirements, actual > issuance practices, or a CA's or drafter's intent.) > I think that Mozilla should make a public judgement call as to whether the ambiguity is sufficient to require an incident report. I don't think there's a great objective scale against which to make this judgement. One can imagine things like "a reasonable reader" (similar to the US legal system's "reasonable person") being invoked, but I don't know exactly how to structure that. At the end of the day, Mozilla is the entity that has the ability to close Bugzilla tickets, so Mozilla is the entity that has to decide -- in public -- whether the ticket gets to be closed or not. > Should Mozilla’s CP/CPS guidance clarify the situations in which > descriptive statements would be considered commitments, and should we > explain how to handle genuinely unclear statements? > I think that Mozilla should require that CPS documents contain no RFC 2119 keywords, and that combined CP/CPS documents be formatted as I described above: as a CPS, plus an additional paragraph stating adherence to external CPs. This will make it abundantly clear that even descriptive statements are binding, because descriptive statements are the only kind that will be present. Aaron -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/a/mozilla.org/d/msgid/dev-security-policy/CAEmnErczC2kVPRCAxcCUVhwdyzDm%2B%3D545K026xX4n1khvkBVrA%40mail.gmail.com.
