Re: [TLS] Safe ECC usage

Yaron Sheffer <> Sat, 12 October 2013 09:15 UTC

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Date: Sat, 12 Oct 2013 12:15:08 +0300
From: Yaron Sheffer <>
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Subject: Re: [TLS] Safe ECC usage
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Hi Martin,

I like conspiracy theories as much as the next one, but the truth is, we 
simply don't know if NIST P-256 and friends are bugged. OTOH we do know 
that DHE-1024 is too weak.

Luckily, TLS negotiates ECDHE curves. So on the server side you can 
prefer Brainpool and fall back to P-256. Or you can allow *only* 
Brainpool (or DJB's latest, or whatever) and switch to DHE or to plain 
RSA if the client doesn't have your favorite curve. The point is, ECDHE 
was engineered correctly with built-in crypto agility, so if we move to 
it we have a way forward.


On 10/12/2013 07:50 AM, Martin Rex wrote:
> Really, the best that could happen to the NSA is that everyone starts
> using ECDHE with Nist curves, aka Suite B.  It just would not make sense
> (and amount to a huge waste of tax dollars) if these were _not_ bugged!
> The defects in (EC)DSA look rather accidental to me, and EC_Dual_DRNG was
> deliberatly set up to deceive folks on what was _really_ subverted.
> Considering how it is being used, ECDHE as part of Suite B is the
> single point of failure that is by far the most convenient, because
> it will work for large-scale passive eavesdropping.
> -Martin