Re: [Trans] Threat model outline, attack model

Tao Effect <> Sat, 27 September 2014 16:59 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id 2DE491A1BCE for <>; Sat, 27 Sep 2014 09:59:00 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.334
X-Spam-Status: No, score=-1.334 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_SOFTFAIL=0.665] autolearn=no
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id Ggc-W-F7nq1b for <>; Sat, 27 Sep 2014 09:58:59 -0700 (PDT)
Received: from ( []) by (Postfix) with ESMTP id 2ED881A1BB8 for <>; Sat, 27 Sep 2014 09:58:59 -0700 (PDT)
Received: from (localhost []) by (Postfix) with ESMTP id 1CB8763406F; Sat, 27 Sep 2014 09:58:58 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed;; h= content-type:mime-version:subject:from:in-reply-to:date:cc :message-id:references:to;; bh=kfb+qnR+hjIHTYgWP etvj971n5c=; b=D7YKAQznys85oinv3sWCLuf9I1CzHTP8jo4EsdrtpOwP3yba6 JsurWTQbUHCGcPr2jjVq5GkXbJ51mAUSMD/0++BCtLo19yKi9/SmKVdCyzWF7Q7H yXb14ZigMcd5e9h2n9yn//9VRgdPWiczEBkISJTKKZZmkNQtbpD/B3QvqQ=
Received: from [] ( []) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: by (Postfix) with ESMTPSA id A533263406C; Sat, 27 Sep 2014 09:58:57 -0700 (PDT)
Content-Type: multipart/signed; boundary="Apple-Mail=_D55F2E67-BE92-491D-92A2-880754B25C36"; protocol="application/pgp-signature"; micalg=pgp-sha512
Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\))
X-Pgp-Agent: GPGMail 2.1 (f76fd85)
From: Tao Effect <>
In-Reply-To: <>
Date: Sat, 27 Sep 2014 09:58:56 -0700
X-Mao-Original-Outgoing-Id: 433529936.628428-9c66d1b14f981fa2812d28ac4ef8d529
Message-Id: <>
References: <> <> <> <> <> <> <> <> <> <> <>
To: Ben Laurie <>
X-Mailer: Apple Mail (2.1878.6)
Cc: Paul Wouters <>, "" <>
Subject: Re: [Trans] Threat model outline, attack model
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Public Notary Transparency working group discussion list <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Sat, 27 Sep 2014 16:59:00 -0000

Dear Ben,

On Sep 27, 2014, at 4:53 AM, Ben Laurie <> 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.