Re: [dmarc-ietf] ARC questions

"Douglas E. Foster" <> Sun, 22 November 2020 20:35 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 197AB3A0CE7 for <>; Sun, 22 Nov 2020 12:35:04 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -0.198
X-Spam-Status: No, score=-0.198 tagged_above=-999 required=5 tests=[DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (1024-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id H5R6naGuwSZ7 for <>; Sun, 22 Nov 2020 12:35:02 -0800 (PST)
Received: from ( []) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 63C433A0CE4 for <>; Sun, 22 Nov 2020 12:35:02 -0800 (PST)
X-ASG-Debug-ID: 1606077298-11fa313c012c240001-K2EkT1
Received: from ( []) by with ESMTP id qTkN8VLz2EXSxxHN (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NO) for <>; Sun, 22 Nov 2020 15:34:58 -0500 (EST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=s1025; h=message-id:reply-to:subject:to:from; bh=H91CJzHpJhbhZzl41gAzYahqWpv0+VLl6Ko21TU/+Fs=; b=GpO4Ez/PF43q1rs54hRH4I+a7ZbCMR44LND1Jdk/WvUIdvqoKCPTKYtYq/UiHMmIa AyED0sJlCEMZ3GK0w+81XoT30bquu+e5dwGuZFit+mNsGgFDVfTKXUdHswf5zfR+8 sU86qiFoPOmcKtHRip5OCL4Mw3kuN3Br+TbDUHwfk=
From: "Douglas E. Foster" <>
To: <>
Date: Sun, 22 Nov 2020 15:34:49 -0500
X-ASG-Orig-Subj: Re: [dmarc-ietf] ARC questions
Message-ID: <>
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary=2d0007a3f68b4a9192a6628af8f6929a
In-Reply-To: <20201122200119.1D77527BB031@ary.qy>
References: <20201122200119.1D77527BB031@ary.qy>
X-Exim-Id: d64e6e7bf2b44936a4129492c934bb33
X-Barracuda-Start-Time: 1606077298
X-Barracuda-Encrypted: ECDHE-RSA-AES256-SHA384
X-Virus-Scanned: by bsmtpd at
X-Barracuda-Scan-Msg-Size: 5443
X-Barracuda-BRTS-Status: 1
X-Barracuda-Spam-Score: 0.50
X-Barracuda-Spam-Status: No, SCORE=0.50 using global scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests=BSF_RULE7568M, HTML_MESSAGE
X-Barracuda-Spam-Report: Code version 3.2, rules version Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- 0.00 HTML_MESSAGE BODY: HTML included in message 0.50 BSF_RULE7568M Custom Rule 7568M
Archived-At: <>
Subject: Re: [dmarc-ietf] ARC questions
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Domain-based Message Authentication, Reporting, and Compliance \(DMARC\)" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Sun, 22 Nov 2020 20:35:04 -0000

Apologies.    Either I read an obsolete version of the document, an unrelated document, or have a hallucinating memory.   Hoping it is not my mind going south...



From: "John Levine" <>
Sent: 11/22/20 3:01 PM
Subject: Re: [dmarc-ietf] ARC questions

In article <> you write:
>On 11/22/20 11:18 AM, Douglas E. Foster wrote:
>> ARC has a very limited set of items included in the signature.? ?Body
>> hash is purposefully excluded.? So it is the same signature algorithm
>> but with different parameters and a different purpose.? Therefore it
>> has a different header label .
>Now wait, Kurt just said that the body hash is included. Somebody has to
>be wrong here.

Doug is mistaken. The ARC-Message-Signature (AMS) header has the same
body hash as a DKIM signature.

dmarc mailing list