Subject: [saag] Using Ed25519 / Ed448 for encryption

From: Phillip Hallam-Baker <[email-masked]>
Date: Tue, 2 Oct 2018 22:37:13 -0400

OK, so why would someone want to do this when we have the Montgomery
curves? There are two answers.

First, if there is going to be crypto accelerator hardware, VLSI fabs are
likely to want to have one coprocessor for one algorithm rather than two.

Second, the meta-cryptographic techniques I am using in the Mesh don't work
using the Montgomery ladder approach. I need to be able to add arbitrary
points. So to use the CurveX implementations, I would have to convert the
points to Edwards, add and convert back.

For the Mesh, I am just using Ed448 for both. But I am going to have to
start thinking about other applications soon.

Should I write a draft describing how to convert between the curves with
some test vectors or a draft on my approach to using Ed448 for key
agreement?

---

From: Mohit Sethi <[email-masked]>
Date: Wed, 3 Oct 2018 07:23:16 +0300

FYI:

https://tools.ietf.org/html/draft-struik-lwig-curve-representations-02

"specifies how to represent Montgomery curves and (twisted) Edwards 
curves as curves in short-Weierstrass form and illustrates how this can 
be used to implement elliptic curve computations using existing 
implementations that already implement, e.g., ECDSA and ECDH using NIST 
prime curves."

--Mohit
On 10/03/2018 05:37 AM, Phillip Hallam-Baker wrote:
> First, if there is going to be crypto accelerator hardware, VLSI fabs 
> are likely to want to have one coprocessor for one algorithm rather 
> than two.
>
> Second, the meta-cryptographic techniques I am using in the Mesh don't 
> work using the Montgomery ladder approach. I need to be able to add 
> arbitrary points. So to use the CurveX implementations, I would have 
> to convert the points to Edwards, add and convert back.
>
> For the Mesh, I am just using Ed448 for both. But I am going to have 
> to start thinking about other applications soon.
>
> Should I write a draft describing how to convert between the curves 
> with some test vectors or a draft on my approach to using Ed448 for 
> key agreement?
>
>
>
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> saag mailing list
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