Re: [Acme] Signature misuse vulnerability in draft-barnes-acme-04

Jacob Hoffman-Andrews <jsha@eff.org> Thu, 13 August 2015 17:25 UTC

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Date: Thu, 13 Aug 2015 10:24:58 -0700
From: Jacob Hoffman-Andrews <jsha@eff.org>
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Subject: Re: [Acme] Signature misuse vulnerability in draft-barnes-acme-04
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> Yep, I get that. I might be misreading it, but it looked like the
> suggestion of a /.well-known URI for account keys would impact all
> ACME users, not just those using Simple HTTP validation.
I didn't fully expand the idea, but my assumption was that similar
continuous publication techniques could apply to other challenge types.
For instance, DVSNI could involve answering for a
<identifier>.acme.invalid at any time with a test certificate embedding
a list of account keys or account key hashes in some format. Similarly,
one could publish a list of account key hashes in DNS.