Re: [Dcrup] Is there anything this WG wants to do not yet in draft-ietf-dcrup-dkim-crypto-01 ?
Eric Rescorla <ekr@rtfm.com> Tue, 20 June 2017 17:38 UTC
Return-Path: <ekr@rtfm.com>
X-Original-To: dcrup@ietfa.amsl.com
Delivered-To: dcrup@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 766601315C7 for <dcrup@ietfa.amsl.com>; Tue, 20 Jun 2017 10:38:11 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.599
X-Spam-Level:
X-Spam-Status: No, score=-2.599 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=rtfm-com.20150623.gappssmtp.com
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 1nhyWcvY5Sne for <dcrup@ietfa.amsl.com>; Tue, 20 Jun 2017 10:38:09 -0700 (PDT)
Received: from mail-yw0-x22d.google.com (mail-yw0-x22d.google.com [IPv6:2607:f8b0:4002:c05::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 30EE51315B8 for <dcrup@ietf.org>; Tue, 20 Jun 2017 10:38:09 -0700 (PDT)
Received: by mail-yw0-x22d.google.com with SMTP id 63so55186201ywr.0 for <dcrup@ietf.org>; Tue, 20 Jun 2017 10:38:09 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rtfm-com.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=8wSxAJ+gHi0g98hDB1dbU7MZgAdNdntUI/snG/7ca/4=; b=lFmO/1V2o4iKJCw2F3DfXx7sLy+mxDF/l3zqZhGV/wHQFXAJLaA10y3CWuy7A8HkuQ QkcC5CyxuF1QuElPEsvgq/pkMPWERPyMG1ncL04lWb8eA7e2PrzBoxRu4LQwVWtxKT0+ rrZZ5MmEYZ2ewOqbt8hXT4kSPPO+SLqth+znOOqSGjhcymKqHu2Q4nAQQwMQNPJeluil LIopxxtk5w7nxDu54ieCObA18Pb/y030l8mBqjy43Mmyg4vUQOQ3H6agYsh3YaHskThv UYcWtHE+0+9HdNHDgdboF5OBzYjOLTFverzGHRPN6fE/ZierjOMpqGab/enJIwZ3Tu1Y mnzw==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=8wSxAJ+gHi0g98hDB1dbU7MZgAdNdntUI/snG/7ca/4=; b=WsINHZrxZ4dBxU8H11lH1jzw249vlDHHsSAcg/isrUlk4DOgdf1NzJN9e315PYfJDe W06NYExQErVLyZ8ZwmjZajquSAX3kNeMEBc/alfwctI1qlgo2EfuOODpMoHFK/HIzVbI EwoRelmk62tbM7gwwEbft1qUaZwcC7XyDDEbJ9+hTT8417abJTJhmK5ieHgCMHwrtMWR 9WNUzCfTdaDTSPT6/Q46DPfVKJ50bREj+TI8jnm3olCfpDT0/aR/RpkSs8+Mj+3CQCgD EbrIl39KA0OgFAvRlgweOXvTnI0OaW5VhJM5b4ux3UHj8PK6K/g34b+gpBQu/jLvqMo3 lUyw==
X-Gm-Message-State: AKS2vOzWYACFLldkZAICLgq+o4fmmgFcCuTBNV5QEjiWcJJTXQIACilQ G6ce7odDOghbiS4eHz+LO8AqxeyMbgApjDA=
X-Received: by 10.129.109.4 with SMTP id i4mr24872562ywc.3.1497980288328; Tue, 20 Jun 2017 10:38:08 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.13.215.9 with HTTP; Tue, 20 Jun 2017 10:37:27 -0700 (PDT)
In-Reply-To: <alpine.OSX.2.21.1706201134480.33510@ary.qy>
References: <alpine.OSX.2.21.1706121103510.19565@ary.local> <20170619205309.10839.qmail@ary.lan> <c05aa9933039406d8401c1b1ca95437c@usma1ex-dag1mb1.msg.corp.akamai.com> <CABcZeBMvofEg+=qCEwDNa6=O8pK+o4XXRRYW8p=uH=oXV-PM-w@mail.gmail.com> <alpine.OSX.2.21.1706201134480.33510@ary.qy>
From: Eric Rescorla <ekr@rtfm.com>
Date: Tue, 20 Jun 2017 10:37:27 -0700
Message-ID: <CABcZeBNoOwbRqcs4Z7A6SDXZ5Hd0MDVcOgDkdbpoo-P0w4eZfw@mail.gmail.com>
To: John R Levine <johnl@taugh.com>
Cc: "dcrup@ietf.org" <dcrup@ietf.org>
Content-Type: multipart/alternative; boundary="001a114dd184f7aedc055267b617"
Archived-At: <https://mailarchive.ietf.org/arch/msg/dcrup/4duYtVaCzjNlrPJO3b0_gkshfWk>
Subject: Re: [Dcrup] Is there anything this WG wants to do not yet in draft-ietf-dcrup-dkim-crypto-01 ?
X-BeenThere: dcrup@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: DKIM Crypto Update <dcrup.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dcrup>, <mailto:dcrup-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dcrup/>
List-Post: <mailto:dcrup@ietf.org>
List-Help: <mailto:dcrup-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dcrup>, <mailto:dcrup-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 20 Jun 2017 17:38:11 -0000
On Tue, Jun 20, 2017 at 9:50 AM, John R Levine <johnl@taugh.com> wrote: > Giving this document a quick read I see several things I would change. >> > > In case it's not clear, I do not purport to be any sort of crypto expert, > so I'm hoping that you, r$, et al. help us to be sure that what I say makes > sense. > > 1. You say you are using EdDSA with SHA-256? Does this mean you intend >> to use the HashEdDSA variant see ( >> https://tools.ietf.org/rfcmarkup?doc=8032#section-4)? If so you >> should say so. >> > > I think the answer is no. DKIM signatures use two chained hashes. First > it hashes a canonicalized version of the message body, and inserts the > base64 hash into the DKIM-Signature header. Then it hashes a canonicalized > version of the headers, signs that hash, and inserts the base64 signature > of the second hash into the DKIM-Signatuer header. To avoid infinite > regress, the verification step pretends the signature wasn't in the header > when verifying. > > As far as I can tell, feeding the canonicalized header text into HashEdDSA > gives the same result as feeding the hash into PureEdDSA. Since the > hashing in DKIM has been defined for a decade and we're not planning to > change it (other than to deprecate SHA-1) I'd rather say this is a > PureEdDSA signature of the existing hash. OK, I think this probably needs to be clearer in the document. 2. I wouldn't specific generic EdDSA but rather EdDSA with a specific >> curve. This is both for practical reasons (I don't want to have to >> distinguish keys by len()) and for algorithmic reasons (you want to >> use a stronger digest algorithm than SHA-256 with X448) >> > > OK. Looking at 8032, it appears I want to use Ed25519, right? Yes, I think so. -Ekr 3. You shouldn't name the keys ecdh(fp) but rather eddsa(fp) These keys >> are not intended for use with key exchange but rather signature. The >> document actually seems kinda confused on this point with the text >> saying one thing and the table saying another. >> > > OK. > > Regards, > John Levine, johnl@taugh.com, Taughannock Networks, Trumansburg NY > Please consider the environment before reading this e-mail. https://jl.ly >
- [Dcrup] combo update draft-ietf-dcrup-dkim-crypto… John R Levine
- Re: [Dcrup] combo update draft-ietf-dcrup-dkim-cr… Martin Thomson
- Re: [Dcrup] combo update draft-ietf-dcrup-dkim-cr… John R Levine
- Re: [Dcrup] combo update draft-ietf-dcrup-dkim-cr… Martin Thomson
- Re: [Dcrup] Is there anything this WG wants to do… John Levine
- Re: [Dcrup] Is there anything this WG wants to do… Salz, Rich
- Re: [Dcrup] Is there anything this WG wants to do… Eric Rescorla
- Re: [Dcrup] Is there anything this WG wants to do… John R Levine
- Re: [Dcrup] Is there anything this WG wants to do… Eric Rescorla
- Re: [Dcrup] Is there anything this WG wants to do… Jon Callas
- Re: [Dcrup] key rotation, was Is there anything t… John R Levine
- Re: [Dcrup] Is there anything this WG wants to do… Scott Kitterman
- Re: [Dcrup] Is there anything this WG wants to do… Scott Kitterman
- Re: [Dcrup] Is there anything this WG wants to do… John R. Levine
- Re: [Dcrup] Is there anything this WG wants to do… John R. Levine
- Re: [Dcrup] Is there anything this WG wants to do… Scott Kitterman
- Re: [Dcrup] Is there anything this WG wants to do… Peter Goldstein