Re: [Cfrg] A downside of deterministic DL signatures?

Tony Arcieri <bascule@gmail.com> Thu, 31 July 2014 21:09 UTC

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From: Tony Arcieri <bascule@gmail.com>
Date: Thu, 31 Jul 2014 14:09:02 -0700
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To: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
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Cc: Dan Brown <dbrown@certicom.com>, IRTF Crypto Forum Research Group <cfrg@irtf.org>
Subject: Re: [Cfrg] A downside of deterministic DL signatures?
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On Thu, Jul 31, 2014 at 10:23 AM, Daniel Kahn Gillmor <dkg@fifthhorseman.net
> wrote:

> neither of these required nationstate-level effort, and they date back
> to 2008.


Okay, let me put it this way instead:

Collisions:

- Can be used to alter the content of individual messages
- This requires that the design of the hash function itself be broken

Bad nonces:

- Leak the private key which can then be used to forge as many messages as
you wish
- Can be the result of bad RNGs/implementation errata even if the algorithm
and the rest of its implementation is sound

Which is worse?

-- 
Tony Arcieri