Re: [Trans] Threat model outline, attack model

Tao Effect <contact@taoeffect.com> Sat, 27 September 2014 16:59 UTC

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From: Tao Effect <contact@taoeffect.com>
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Date: Sat, 27 Sep 2014 09:58:56 -0700
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To: Ben Laurie <benl@google.com>
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Cc: Paul Wouters <paul@nohats.ca>, "trans@ietf.org" <trans@ietf.org>
Subject: Re: [Trans] Threat model outline, attack model
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Dear Ben,

On Sep 27, 2014, at 4:53 AM, Ben Laurie <benl@google.com> wrote:

> I agree that CT doesn't mitigate mis-issuance for subjects that do not participate.

If by "participate" you mean owners who submit their certs to logs, CT doesn't detect mis-issuance even for those who do, as that email explained.

> On monitors and guarantees - anyone can run a monitor,
> including, of course, the subjects themselves, so clearly there's no
> barrier to participation for subjects who want to participate.

"No barrier"? Subjects (domain owners) would need to monitor *all* the logs out there.

There will be like 1000+ logs out there.

Each log will be how large (gigabytes?), and CT is not P2P, so Monitors must *poll* 1000+ logs constantly for updates, just for the purpose of detecting mis-issuance.

On top of this, Section 4.6 of your RFC (bis-04) states that logs are not required to send monitors everything they ask for, making it unclear whether a log is misbehaving or not.

This is not practical.

###

But that is all besides the point.

The point is that gossip doesn't detect mis-issuance, whether or not "subjects participate" in CT or not.

Kind regards,
Greg Slepak

--
Please do not email me anything that you are not comfortable also sharing with the NSA.