[PATCH] curve25519-sha256 at libssh.org key exchange proposal

[Aris Adamantiadis]

> shared_secret should be an mpint/bignum in the hash, since
> this is what the RFC requires for 'K', c.f. the SSH-ECDH RFC:
>
> http://tools.ietf.org/html/rfc5656#section-4
> 	The elliptic curve public keys (points) that must be transmitted are
> 	encoded into octet strings before they are transmitted.  The
> 	transformation between elliptic curve points and octet strings is
> 	specified in Sections 2.3.3 and 2.3.4 of [SEC1]; point compression
> 	MAY be used.  The output of shared key generation is a field element
> 	xp.  The SSH framework requires that the shared key be an integer.
> 	The conversion between a field element and an integer is specified in
> 	Section 2.3.9 of [SEC1].
> where [SEC1] == http://www.secg.org/download/aid-780/sec1-v2.pdf
>
>
I think [SEC1] is irrelevant here since Curve25519 is defined somewhere
else. I think the key here is "The SSH framework requires that the
shared key be an integer" which I do not believe to be a MUST, but a
reason enough to keep an mpint.
> so I think we should keep the encodings from the patch...
>
> -m
>
So I think the patch is ready :)

Aris