Re: [TLS] Safe ECC usage

mrex@sap.com (Martin Rex) Mon, 30 September 2013 22:50 UTC

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To: Kyle Hamilton <aerowolf@gmail.com>
Date: Tue, 01 Oct 2013 00:50:26 +0200
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From: mrex@sap.com
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Subject: Re: [TLS] Safe ECC usage
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Kyle Hamilton wrote:
> 
> That's all well and good, but perhaps should you try to figure out how your
> functions can in fact be used in such standards as TLS without having to
> resort to pulling hens' teeth?
> 
> Or perhaps apply your (admittedly much better than mine) intellect to
> figure out how to create a single public key from a single private key
> which can be used for both signing and key derivation, thus permitting
> consolidation of both into a single X.509 Certificate structure?  The lack
> of this is in fact a major impediment to using self-signed certificates as
> containers for curve25519 public keys.

I currently do not see any benefit from using EC for digital signatures,
but instead a huge amount of code, complexity and IPR issues (did you
look at the CertiCom idea how to charge?).

What I believe would be more attractive is an alternative to rfc4492
for ECDHE_RSA based on curve25519 (and _just_ curve25519), i.e.
a small number of new cipher suites and an additional ClientKeyExchange
and ServerKeyExchange variant specifically tailord for curve25519, so
that there are real benefits to a full-blown and generic rfc4492 TLS EC
crypto.

-Martin