Re: [TLS] Curve25519 in TLS

Kyle Hamilton <aerowolf@gmail.com> Thu, 12 September 2013 00:03 UTC

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Date: Wed, 11 Sep 2013 17:03:57 -0700
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From: Kyle Hamilton <aerowolf@gmail.com>
To: Rob Stradling <rob.stradling@comodo.com>
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Cc: Simon Josefsson <simon@josefsson.org>, Patrick Pelletier <code@funwithsoftware.org>, "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] Curve25519 in TLS
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Curve25519 is not suitable for authentication.  Ed25519 would be more
appropriate, I think.

-Kyle H


On Tue, Sep 10, 2013 at 1:34 AM, Rob Stradling <rob.stradling@comodo.com>wrote;wrote:

> On 09/09/13 21:08, Simon Josefsson wrote:
>
>> Douglas Stebila <stebila@qut.edu.au> writes:
>>
>>  There are other reasons to support curve25519, including efficiency
>>> and resistance to side-channel attacks because constant-time
>>> implementations.
>>>
>>
>> I agree.  To be able to move forward with standardization of the idea,
>> an Internet Draft may help.  I have create one:
>>
>> http://www.ietf.org/id/draft-**josefsson-tls-curve25519-00.**txt<http://www.ietf.org/id/draft-josefsson-tls-curve25519-00.txt>
>>
>> Feedback most welcome!
>>
>
> Simon, thanks for creating this draft.
>
> draft-merkle-tls-brainpool-04 (on which you've based this new draft) says:
>    "While the ASN.1 object identifiers
>    defined in [RFC5639] already allow usage of the ECC Brainpool curves
>    for TLS (client or server) authentication through reference in X.509
>    certificates according to [RFC3279] and [RFC5480] , their negotiation
>    for key exchange according to [RFC4492] requires the definition and
>    assignment of additional NamedCurve IDs."
>
> Your draft defines a NamedCurve ID for Curve25519, thereby enabling it to
> be used for key exchange.  But what about "(client or server)
> authentication through reference in X.509 certificates..."?
>
> I'm not aware of an equivalent of RFC5639 for Curve25519.  Should we
> create one?  Or could we simply define some new ASN.1 Object Identifiers in
> your draft?
>
> --
> Rob Stradling
> Senior Research & Development Scientist
> COMODO - Creating Trust Online
>
>
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