Re: [art] [saag] Date formats: RFC3339 vs. RFC 5322

Hi Yakov,

I'm inclined to agree with Carsten.
RFC 3339 section 5 seems to cover the general guide and recommends use of
ISO 8601 for internet protocols. To the point on fractions of a second with
RFC 3339 § 5.3 Rarely Used Options.

Then my current understanding when a rarely used option is needed for
communicating an information interchange that needs such precision the use
of
ISO 8601-1:2019 and ISO 8601-2:2019 contain the guidance for what should be
used.

That being noted, was there something of security interest that is not
fully covered by RFC 3339, ISO 8601-1:2019 and ISO 8601-2:2019 or a
proposed RFC for SAAG that is not covered by these standards that we can
look at specifically that you're concerned about? If so, please provide
your specific concerns.

With Regard,

Kronah Wood
Metapolymath, LLC
PO Box 19236
Lenexa, KS 66219-9236
+1.2139158297

Sent from Mobile

On Sat, Apr 17, 2021, 7:30 PM Carsten Bormann <cabo@tzi.org> wrote:

> On 2021-04-14, at 22:53, Mark Baushke (ietf) <mbaushke@gmail.com> wrote:
> >
> > Twelve digits after the decimal point expresses pico seconds which is
> just silly and unrealistic at present, but micro seconds seem plausible in
> many contexts. If new standards are forward looking, then the expression
> should possibly be considered.
> > (I do not see a need to consider femto, atto, zepto, or yacto seconds at
> the present time.)
>
> I don’t know why this discussion is continuing on the SAAG list, but let
> me add one factoid anyway:
>
> The CBOR tag defined in draft-bormann-cbor-time-tag supports picosecond
> resolution [1] because the Haskell date/time libraries need that (which in
> turn probably just try to be one step ahead of UNIX nanosecond
> resolution).  (The CBOR tag also has femtosecond and attosecond resolution,
> because these are still cheap with 64-bit integers.  Zeptoseconds,
> yoctoseconds, and anything else down to and beyond Planck units can be
> added later based on bignums.)
>
> A light-nanosecond is ~ 300 mm (~ a foot), a light-picosecond still is ~
> 0.3 mm (~   12 thou), which is well beyond the tolerances to which e.g.
> connectors can be manufactured, so while these are not easy to achieve as
> date-time precisions, as durations (time differences) they are in wide use
> (as are femtoseconds and even attoseconds).
>
> RFC 3339 has no problem with decimal fractions at all, so there is no need
> for invention as long as we talk about text strings for date-times.
>
> Grüße, Carsten
>
> [1]:
> https://www.ietf.org/archive/id/draft-bormann-cbor-time-tag-04.html#name-keys-3-6-9-12-15-18
>
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