Re: [dane] Improving DANE S/MIME Privacy

Paul Wouters <paul@nohats.ca> Tue, 11 April 2017 19:15 UTC

Return-Path: <paul@nohats.ca>
X-Original-To: dane@ietfa.amsl.com
Delivered-To: dane@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 2977912EC8C for <dane@ietfa.amsl.com>; Tue, 11 Apr 2017 12:15:12 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.001
X-Spam-Level:
X-Spam-Status: No, score=-2.001 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RP_MATCHES_RCVD=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=nohats.ca
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id l_P74AbApJJM for <dane@ietfa.amsl.com>; Tue, 11 Apr 2017 12:15:11 -0700 (PDT)
Received: from mx.nohats.ca (mx.nohats.ca [193.110.157.68]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 45F5F12EC95 for <dane@ietf.org>; Tue, 11 Apr 2017 12:15:04 -0700 (PDT)
Received: from localhost (localhost [IPv6:::1]) by mx.nohats.ca (Postfix) with ESMTP id 3w2cFL64X9z314; Tue, 11 Apr 2017 21:15:02 +0200 (CEST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nohats.ca; s=default; t=1491938102; bh=LmC13GJ5T05Lc8UVNCsSFJfX/JhffC0IufAfbVBrQ9E=; h=Date:From:To:cc:Subject:In-Reply-To:References; b=fvIXa8/We84fGbFNWSE58/dK9t+E+eT5qlbtRvzyhWtwgao9+nRzMAKfFkARV2Y4x /1H6kFI3EfwCNQ1E9bQ3umyIA83Drw1eLsDL4O4+6s40E1BNwPh+TiVpLD3Xueus96 64Vni74+iTVA5z/r8brvuuyvO7R2LfPlURJbg2iY=
X-Virus-Scanned: amavisd-new at mx.nohats.ca
Received: from mx.nohats.ca ([IPv6:::1]) by localhost (mx.nohats.ca [IPv6:::1]) (amavisd-new, port 10024) with ESMTP id TUCyE_8eISJ8; Tue, 11 Apr 2017 21:15:02 +0200 (CEST)
Received: from bofh.nohats.ca (bofh.nohats.ca [76.10.157.69]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx.nohats.ca (Postfix) with ESMTPS; Tue, 11 Apr 2017 21:15:02 +0200 (CEST)
Received: by bofh.nohats.ca (Postfix, from userid 1000) id 30F8F418516; Tue, 11 Apr 2017 15:15:01 -0400 (EDT)
DKIM-Filter: OpenDKIM Filter v2.11.0 bofh.nohats.ca 30F8F418516
Received: from localhost (localhost [127.0.0.1]) by bofh.nohats.ca (Postfix) with ESMTP id 199BF40D3585; Tue, 11 Apr 2017 15:15:01 -0400 (EDT)
Date: Tue, 11 Apr 2017 15:15:00 -0400 (EDT)
From: Paul Wouters <paul@nohats.ca>
To: Alice Wonder <alice@domblogger.net>
cc: dane@ietf.org
In-Reply-To: <f7332bd5-f003-c828-8f4a-0d543099c872@domblogger.net>
Message-ID: <alpine.LRH.2.20.999.1704111513480.15830@bofh.nohats.ca>
References: <f7332bd5-f003-c828-8f4a-0d543099c872@domblogger.net>
User-Agent: Alpine 2.20.999 (LRH 202 2017-01-01)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII; format=flowed
Archived-At: <https://mailarchive.ietf.org/arch/msg/dane/b2xJ-WlBzuTb6BsaasdIYOipD1g>
Subject: Re: [dane] Improving DANE S/MIME Privacy
X-BeenThere: dane@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: DNS-based Authentication of Named Entities <dane.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dane>, <mailto:dane-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dane/>
List-Post: <mailto:dane@ietf.org>
List-Help: <mailto:dane-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dane>, <mailto:dane-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 11 Apr 2017 19:15:12 -0000

On Tue, 11 Apr 2017, Alice Wonder wrote:

> If the serial number for the x.509 certificate is a salt for the hash, then 
> spammers can not determine the validity of an e-mail address from DNS but 
> those who already have the certificate can use DNS to DANE validate the 
> certificate.

Except the whole point of this record is to publish that certificate, so
clearly the spammers have a copy of the serial number too :)

Paul