Re: [sacm] AD Review of draft-ietf-sacm-coswid-15

[Carsten Bormann <[e-mail]>]

On 2020-11-15, at 20:15, Roman Danyliw <[e-mail]> wrote:
> 
> 
> ** Section 2.9.4.  The date field here is a CDDL time type.  In SWID, the equivalent is a xs:date.  Wouldn't it be more appropriate to use a CDDL tstr here?
> [Update: I see you're tracking this and have a marker for it with [QUESTION: Is "time" a correct representation of XSD:date?]”

By now, we have RFC 8943, which defines two representations of calendar date:

   Tag:  1004
   Data Item:  UTF-8 text string
   Semantics:  [RFC3339] full-date string
   Reference:  RFC 8943

   Tag:  100 (ASCII 'd')
   Data Item:  Unsigned or negative integer
   Semantics:  Number of days since the epoch date 1970-01-01
   Reference:  RFC 8943

So tag 1004 is directly equivalent to xs:date’s XML text form, while tag 100 is a compact form of that that would be more appropriate for COSWID in my view.  
[Note that the conversion between the two is entirely based on the principles of the Gregorian calendar, it will not be messed with by politicians (and their desire to get a memorial monument by messing with time zones) or by the time-nuts and their leap seconds.]

               +==================+==============+=========+
               | Date             | Tag 1004     | Tag 100 |
               +==================+==============+=========+
               | October 9, 1940  | "1940-10-09" | -10676  |
               +------------------+--------------+---------+
               | December 8, 1980 | "1980-12-08" | 3994    |
               +------------------+--------------+---------+

                                  Table 1

As usual, we can import the definitions made in this RFC into other RFCs without necessarily using it *as a tag* (i.e., we can use a tag in unwrapped form, if desired).

Grüße, Carsten