tree 74aca7d7d93fb710afb3e282ce28c164fa3ec710
parent 9b076918e3c7e908b2bdea932f272a9979f2488a
author Filippo Valsorda <filippo@golang.org> 1647098519 -0500
committer Filippo Valsorda <filippo@golang.org> 1647301593 +0000

ssh: add diffie-hellman-group14-sha256 kex

RFC 9142 made diffie-hellman-group14-sha256 from RFC 8268 a MUST, and
it's strictly better than diffie-hellman-group14-sha1, which we already
have, and trivial to add.

> The method of key exchange used for the name "diffie-hellman-
> group14-sha256" is the same as that for "diffie-hellman-group14-sha1"
> except that the SHA256 hash algorithm is used.

Ignore the bigger groups which have a meaningful performance cost, and
don't share the same interoperability benefit.

Adapted from CL 387994.

Fixes golang/go#31731

Co-authored-by: Nicola Murino <nicola.murino@gmail.com>
Change-Id: Id4ce345a2065840f193986739ea890f105a1e929
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/392014
Trust: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Roland Shoemaker <roland@golang.org>