Re: [TLS] Curve25519 in TLS and Additional Curves in TLS

[Alyssa Rowan <[e-mail]>]

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On 11 April 2014 08:33:42 BST, Nikos Mavrogiannopoulos <[e-mail]> wrote:
>> Assuming all side-channel attacks require repetition seems like the
>> kind of rather dangerous thinking that has bought TLS very unpleasant
>> surprises in the past. We've had quite enough of those already, I think.
>Could you elaborate on how to achieve repetition on a protocol that runs
>only once with the same key? I find your argumentation hard to follow.

Perhaps you misunderstand. Naïvely assuming that every dangerous side-channel attack absolutely needs amplification via repetition is, I feel, optimistic (or, depending on your point of view, pessimistic).

(And if I ever develop such a one-shot attack, I shall name it something like #yolo, because cute attack names are in vogue.)

That's the kind of thinking that got us 20:20 hindsight gems like '[this timing attack] is not believed to be large enough to be exploitable'. Please let's be more careful.

Using good Curve25519 implementations gives us the opportunity to eliminate potential side-channels. Don't waste that opportunity.

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/akr
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