[cabfpub] Durations

[Peter Bowen]

I’ve been trying to calculate the potential impact of various recent proposals by looking at existing known certificates.  One thing that has become very obvious is that durations in units of whole “years” or “months” are actually really hard to calculate.  Consider a certificate with notBefore of 2016-07-31 00:00:00 +0000 and notAfter of 2017-08-31 23:59:59 +0000.  This is, at least to me, pretty clearly a 13 month duration.  It is also 34300799 seconds, which works out to 396.9999884 days, which is longer than the obvious definition of 13 months.

As people are drafting ballots, can you please consider specifying intervals in days and using the maximum case for the interval (assuming leap years, long months, leap seconds, rounding etc)?  For example, if you want to specify 13 months, please consider using 366 + 31 + 1 = 398 days.

Thanks,
Peter