Re: [dane] email canonicalization for SMIMEA owner names

[Alexey Melnikov <[e-mail]>]

On 12/12/2014 11:37, Ben Laurie wrote:
> On 11 December 2014 at 19:51, Rose, Scott W. <[e-mail]> 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 "[e-mail]" 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.
This is a bit misleading: MSA or intermediate MTAs can't know that these 
are the same (unless MSA is also the final MTA).
> 2. What about GMail's [e-mail] == [e-mail] ==
> [e-mail] == [e-mail]?
As above.