Re: [PATCH 0/7] crypto: add eddsa support for x509(Internet mail)

[hongbo li <herbert.tencent@gmail.com>]

Eric Biggers <ebiggers@kernel.org> 于2021年5月18日周二 上午5:21写道：
>
> On Thu, May 13, 2021 at 02:44:07PM +0000, herberthbli(李弘博) wrote:
> > 在 2021/5/13 3:12, Eric Biggers 写道:
> >
> > On Wed, May 12, 2021 at 10:04:07PM +0800, Hongbo Li wrote:
> >
> >
> > From: Hongbo Li <herberthbli@tencent.com><mailto:herberthbli@tencent.com>
> >
> > This series of patches add support for x509 cert signed by eddsa,
> > which is described in RFC8032 [1], currently ed25519 only.
> >
> >
> >
> > It would be helpful to explain how this is related to the kernel's existing
> > Curve25519 support.
> >
> > - Eric
> >
> >
> > Curve25519 is an elliptic curve used for key agreement(ECDH). It is a Montgomery curve.
> >
> > Edwards25519 is a twisted Edwards curve and birationally equivalent to Curve25519, the
> > birational maps are described in rfc7748 section 4.1.
> > https://datatracker.ietf.org/doc/html/rfc7748#section-4.1
> >
> >
> > Ed25519 is a Digital Signature Algorithm over Edwards25519.
> >
>
> Sure, but what does that mean in terms of code.  Can you reuse any of the code,
> and if not why not?  I *think* the answer is no, but this is a common point of
> confusion, so it would be helpful to properly explain this...
>
> - Eric

Thank you for your review. No, the eddsa can't reuse the code of curve25519.
I'll also explain this in the next version of patches.
Regards,
Hongbo