Re: [xcbf] Question about X9.84

[Bancroft Scott <baos@oss.com>]

On Thu, 11 Apr 2002, Alessandro Triglia wrote:

> Phil,
>
> I have a question about X9.84.
>
> In X9.84, relative OID fields are used to carry dates/times.
>
> However, it is not clear to me how the "z" component (the seventh
> component) of the relative OID is to be used.
>
> This component corresponds to the "zone designator" of GeneralizedTime,
> which indicates:
>
>    a) that the time value is a UTC time (when the zone designator is set to
> "Z");
>
>    b) that the time value is a local time, with no indication of how local
> time relates to UTC (when the zone designator is absent);
>
>    c) that the time value is a local time, with an indication of the
> difference between local time and UTC (when the zone designator is set to
> hours, or hours + minutes).
>
> Can you please clarify how this component is to be used?  What is the
> implication of its absence, what information does it carry when present,
> and how is this information represented?

Consider the following:

   example DateTime ::= {
      year(2001) month(1) day(1) hours(0) minutes(0) seconds(0) z(0)
   }

I see no canonical/non-canonical issue here as far as the encoding rules
go.  There are strict rules on how values should be encoded for
RELATIVE-OID.  If someone omitted the z or seconds or whatever, there is
no way for a tool to catch it.  Seems to me that this issue has to be
resolved strictly at the application level - if it is an issue.

Phil, are there any sender's option as far as DateTime goes?  If no,
I don't see any problems here, in that once someone does an encoding
of the value the recipient can get a different encoding (if they were
to re-encode the value) only if they changed the DateTime value.

Hmmm ... is there a relationship to DER?  Is there some sort of conversion
of this time format to/from GeneralizedTime?

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