[PATCH] g10: Fix ECDH secret compressed/uncompressed format

Arnaud Fontaine arnaud.fontaine at ssi.gouv.fr
Tue Oct 25 09:14:45 CEST 2016

Le 25/10/2016 03:49, NIIBE Yutaka a écrit :
> I interpret that "the compressed format" means x-coordinate only
> in Jivsov's proposal:
>     https://tools.ietf.org/html/draft-jivsov-ecc-compact-05
> For ECDH, we don't need to care about the key generation constraint.
> I think that it is good for OpenPGP card specification to address
> the point format representation:
>     04 || X || Y
>     or
>     X only, with no prefix
> I think that the original compressed format of SEC (02 or 03 prefix)
> is covered by the patent by HP.

My comment "Compressed format" is actually imprecise, it is the raw x coordinate
(without any prefix), as it is the expected output shared secret of ECDH.

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