Re: [dane] email canonicalization for SMIMEA owner names

Alexey Melnikov <alexey.melnikov@isode.com> Fri, 12 December 2014 17:01 UTC

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Date: Fri, 12 Dec 2014 17:01:22 +0000
From: Alexey Melnikov <alexey.melnikov@isode.com>
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To: Ben Laurie <benl@google.com>
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Cc: Paul Wouters <paul@nohats.ca>, dane WG list <dane@ietf.org>
Subject: Re: [dane] email canonicalization for SMIMEA owner names
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On 12/12/2014 16:28, Ben Laurie wrote:
> On 12 December 2014 at 15:56, Alexey Melnikov <alexey.melnikov@isode.com> wrote:
>> On 12/12/2014 15:38, Paul Wouters wrote:
>>> Whoever starts using variant email addresses should publish records for
>>> it? As John said, clients shouldn't start guessing addressing schemes used
>>> by others
>> +1. Nobody other than the final MTA/MDA knows that certain forms are
>> equivalent.
> True, but does not make your scheme workable.
Only publish canonical form or variants that were used for sending 
emails out?
>>> Sent from my iPhone
>>>
>>>> On Dec 12, 2014, at 06:37, Ben Laurie <benl@google.com> wrote:
>>>>
>>>>> On 11 December 2014 at 19:51, Rose, Scott W. <scott.rose@nist.gov>
>>>>> wrote:
>>>>> Realized the other action item I was assigned to from the interim
>>>>> meeting was email canonicalization for SMIMEA.  I believe it stems from
>>>>> Viktor Dukhovni's email to the endymail list:
>>>>> http://www.ietf.org/mail-archive/web/endymail/current/msg00134.html
>>>>>
>>>>> I was wondering if we can borrow a page from RFC 4034 Section 6.2 and
>>>>> include text in the draft Section 3, item 1 in the numbered list:
>>>>>
>>>>>       1.   The user name (the "left-hand side" of the email address,
>>>>> called
>>>>>         the "local-part" in the mail message format definition [RFC2822]
>>>>>         and the "local part" in the specification for internationalized
>>>>>         email [RFC6530]), is hashed using the SHA2-224 [RFC5754]
>>>>>         algorithm (with the hash being represented in its hexadecimal
>>>>>         representation, to become the left-most label in the prepared
>>>>>         domain name.  This does not include the "@" character that
>>>>>         separates the left and right sides of the email address.  The
>>>>>         string that is used for the local part is a Unicode string
>>>>>         encoded in UTF-8 **with all upper case letters converted to their
>>>>>         corresponding lower case letters where appropriate.**
>>>>>
>>>>>
>>>>> The text between the '**' is new.  The goal is to prevent a situation
>>>>> when the email address is "JRandom@example.com" and the SMIMEA is created
>>>>> using "jrandom" as the user name.   Would this be enough, or are there
>>>>> scripts where this would result in different or potentially conflicting
>>>>> owner names?
>>>> Speaking of canonicalisation:
>>>>
>>>> 1. What about X+Y@Z - for almost all MTAs, this is the same as X@Z.
>>>>
>>>> 2. What about GMail's a.b.c@gmail.com == abc@gmail.com ==
>>>> ab.c@gmail.com == a.bc@gmail.com?
>>