Re: [Lwip] I-D Action: draft-ietf-lwig-curve-representations-13.txt

Dear colleagues:

I updated the draft so as to take into account the comments received 
during IETF Last Call.

Changes:

- added verbiage on use of Wei25519 and Wei448 with PKIX and CMS (now 
Section 11) and request for OIDs to support this (now Section 12.1);

- changed requested COSE algorithm registration values: (Section 12.2) 
ECDSA25519 (was: -1; now: -9); ECDH25519 (was: -2; now: -24 {still 
1-octet, though}); (Section 12.3) ECDSA448 (was: -47; now: -48); ECDH448 
(was: -47; now: -48). Note RS: here, latter change due to usurping the 
value of -47 by ECDSA w/ secp256k1 and SHA256 earlier this summer;

- added examples encodings so as to include all cousins of Curve448 (now 
including also Wei448.1, now Appendix O.4);

- added three more rows in Table 1 (Appendix K.4.2) so as to include 
examples for all cousins of Curve448 (now including also Wei448, 
Wei448.1, Wei448.-3);

- added two notes to Appendix K.6 and slightly reformulated so as to 
make these auxiliary functions easier to simply cross-reference and 
instantiate in future (if desired);

- fixed minor detail of 2-isogenous mapping between Wei448 and Wei448.-3 
(singling out point (tau,0) of order two in dual isogeny map in Appendix 
N.2);

- slightly changed encoding example for Edwards448 curve (Appendix O.6), 
to make this consistent with potential future use of randomized 
representation of curve points (Appendix K.5) if one were to ever use 
this for enhanced privacy in big brother-esque scenarios; {details do 
not matter for current draft, though}

- some tiny editorials, including (1) consistent naming of "short" 
Weierstrass curve as short-Weierstrass curves; (2) defined alternative 
naming of "points in small subgroup" as "low-order points" as well 
(Appendix B.1); (3) changed "smaller than 1/2" to "at most 1/2" (at end 
of Appendix P.3). {here, perfectionism seems to get in the way}

While the above list seems long, almost all of this is editorial or 
simply adding other example encodings. The tiny "fix" above is, however, 
a fix (but probably would only be noticeable by mathematicians).

Best regards, Rene

On 2020-11-02 6:54 p.m., internet-drafts@ietf.org wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> This draft is a work item of the Light-Weight Implementation Guidance WG of the IETF.
>
>          Title           : Alternative Elliptic Curve Representations
>          Author          : Rene Struik
> 	Filename        : draft-ietf-lwig-curve-representations-13.txt
> 	Pages           : 131
> 	Date            : 2020-11-02
>
> Abstract:
>     This document specifies how to represent Montgomery curves and
>     (twisted) Edwards curves as curves in short-Weierstrass form and
>     illustrates how this can be used to carry out elliptic curve
>     computations using existing implementations of, e.g., ECDSA and ECDH
>     using NIST prime curves.  We also provide extensive background
>     material that may be useful for implementers of elliptic curve
>     cryptography.
>
>
>
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-ietf-lwig-curve-representations/
>
> There are also htmlized versions available at:
> https://tools.ietf.org/html/draft-ietf-lwig-curve-representations-13
> https://datatracker.ietf.org/doc/html/draft-ietf-lwig-curve-representations-13
>
> A diff from the previous version is available at:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-lwig-curve-representations-13
>
>
> Please note that it may take a couple of minutes from the time of submission
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>
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>
>
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