[cabf_validation] CRL Validity Interval Ballot

Wayne Thayer wthayer at gmail.com
Thu Oct 14 16:34:38 UTC 2021

My conclusion from this discussion is that the ballot should be updated to
specify the validity interval of root CRLs and OCSP responses in days
instead of months, with 397 days a SHOULD and 398 days a MUST. Ryan and
Dimitris, is that correct?

Shall I also create a definition for 'validity interval' and make it
applicable to CRLs and OCSP responses?



On Wed, Oct 13, 2021 at 8:08 AM Ryan Sleevi <sleevi at google.com> wrote:

> On Wed, Oct 13, 2021 at 10:57 AM Dimitris Zacharopoulos (HARICA) <
> dzacharo at harica.gr> wrote:
>> On 13/10/2021 5:17 μ.μ., Ryan Sleevi wrote:
>> On Wed, Oct 13, 2021 at 10:05 AM Dimitris Zacharopoulos (HARICA) <
>> dzacharo at harica.gr> wrote:
>>> 4.9.7 and 4.9.10 have a nextUpdate requirement for Root CRLs and OCSP
>>> responses, and this is set for 12 months. Do we want the same level of
>>> "accuracy" as the CRL/OCSP responses of Subordinate CAs? If we do not, then
>>> we can focus on language about just the CRLs/OCSP responses issued by
>>> "online" CAs, as Wayne has already done at the proposed ballot and there is
>>> no need to make further changes to the BRs.
>>> If I understand your position, you believe we should be specific (to the
>>> second) only for specific requirements, such as those linked to RFC 5280
>>> (validity of a certificate, validity period of a CRL/OCSP response) and not
>>> the other cases (related to request tokens, audit reports, etc). Is that
>>> accurate?
>> Got it. Definite misunderstanding :)
>> To try to rephrase:
>>    - Defining a day to be 86,400 seconds (with caveats) is appropriate
>>    for Section 1.6.4 if the desire is to make this ballot a broader "date
>>    interval" cleanup rather than just the CRL cleanup
>>    - This convention cannot address the "inclusive" aspect; that will
>>    need to remain appropriate for ASN.1 types (certificates, CRLs, OCSP)
>>    - The term "validity period" refers to certificates, and comes from
>>    X.509/RFC 5280. The term "validity interval" is a term we introduced for
>>    OCSP, because CRLs and OCSP responses don't necessarily have 'validity
>>    periods' (intervals, freshness, etc are all concepts used to refer to them)
>>    - Taken together with the previous bullet: This means there still
>>       needs to be definitions specific to those, and within the specific sections
>>       (long-term, this would be the relevant profiles for certificates, CRLs, and
>>       OCSP, rather than the current distributed locations)
>>    - Procedural controls - request tokens, audit reports, etc - still
>>    make sense to define in days
>>       - However, the choice of period - 90 days vs 93 days, 397 days vs
>>       398 days, 31 days vs 32 days - were intentionally selected to
>>       *allow* CAs to have a fixed calendrical schedule, without risk of
>>       violation.
>>       - For example, if you have a 30 day period, then over a year, you
>>       will have shifted 5 to 6 days. You won't be able to, for example, "do
>>       something on the first of every month"
>>       - The "extra day" is to make sure that if you do it at 9am on the
>>       1st of the month prior, you (hopefully unambiguously) have until midnight
>>       of the 1st of the current month, without running afoul
>> Got it. Do you have any guidance or preference for the offline CA
>> CRLs/OCSP responses? Should that continue to be described in months or move
>> into something more specific?
> Days was/is the suggestion. Months being 30 days or 31 days has the
> calendrical drift issue. So 367 days = 1 year/12 months.
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