Re: [Cbor] OID representation (was: Re: Robert Wilton's Discuss on draft-ietf-cbor-tags-oid-06: (with DISCUSS and COMMENT))

Carsten Bormann <cabo@tzi.org> Wed, 21 April 2021 19:00 UTC

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From: Carsten Bormann <cabo@tzi.org>
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Subject: Re: [Cbor] OID representation (was: Re: Robert Wilton's Discuss on draft-ietf-cbor-tags-oid-06: (with DISCUSS and COMMENT))
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On 2021-04-08, at 21:44, Carsten Bormann <cabo@tzi.org> wrote:
> 
> (1) Not establishing any stronger connection between TBD111 and TBD112, i.e. status quo.
> (2) Declaring TBD112 as the preferred encoding of an absolute OID that starts with 1.3.6.1.4.1 (0x2b06010401), but still allowing the use of TBD111 as non-preferred.   This would mean a requirement on decoders implementing TBD111 to also implement TBD112.
> (3) Outlawing any TBD111 starting with (0x2b06010401) and requiring the use of TBD112 in all such cases.  This would mean a requirement on both encoders and decoders.  It would also mean a slight complication in tag factoring: replace all naked byte strings that start with h’2b06010401’ by TBD112(rest) (saving three bytes), unless *all* such byte strings start with h’2b06010401’, in which case these prefixes would all be removed and an outer tag of TBD112 used.
> 
> (2a) would be (2) with a deterministic encoding requirement to use the shortest form (i.e., (3) in deterministic encoding only).

At today’s interim meeting, we opted for (2a).

I have now added the text necessary for this in PR #10 [1].

Please send comments and reviews; I plan to bottle this up in a -04 and a response to Rob by the weekend.

Grüße, Carsten


[1]: https://github.com/cbor-wg/cbor-oid/pull/10