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RE: ァ2.1.3 IRI/URI Canonicalization does not address IRIs with IDNs

From: Martin Duerst <duerst@it.aoyama.ac.jp>
Date: Thu, 10 Apr 2008 19:40:49 +0900
Message-Id: <>
To: "Smith, Kevin, VF-Group" <Kevin.Smith@vodafone.com>, "Felix Sasaki" <fsasaki@w3.org>, "Phil Archer" <parcher@icra.org>
Cc: "Eric Prud'hommeaux" <eric@w3.org>, <public-powderwg@w3.org>, <public-i18n-core@w3.org>

[sorry, but my mailer garbles the non-Japanese, non-ASCII stuff]

At 16:44 08/04/10, Smith, Kevin, VF-Group wrote:
>HI Felix and Eric,
>A quick question, and please forgive my ignorance: it seems possible that
>...could be completely separate domains, i.e., one person in the US buys 
>http://www.xn--exmple-jua.org/ , one in Denmark buys http://www.ex蚓
>ple.org/ . If that situation can arise,

It can't. The "Danish" domain name is being resolved by actually converting
to www.xn--exmple-jua.org. Only www.xn--exmple-jua.org is used on the
wire in the DNS protocol. Top-level registries such as .org will never
hand out literal domains such as xn--exmple-jua.org. On a lower level,
it is technically easy to create such a thing, but it doesn't make
much sense, and it would still be accessible via the "Danish" name.

Regards,    Martin.

>then how can we be sure that 
>http://www.xn--exmple-jua.org/ is in fact http://www.ex蚓ple.org/ ? I am 
>assuming that to a domain reseller, they are simply selling a domain name 
>which consists if a string (less any reserved characters), and hence it 
>would be possible to buy a punycoded version of an IRI.
>Many thanks
>-----Original Message-----
>From: public-powderwg-request@w3.org 
>[mailto:public-powderwg-request@w3.org] On Behalf Of Felix Sasaki
>Sent: 10 April 2008 07:01
>To: Phil Archer
>Cc: Eric Prud'hommeaux; public-powderwg@w3.org; public-i18n-core@w3.org
>Subject: Re: ァ2.1.3 IRI/URI Canonicalization does not address IRIs with IDNs
>Hi Phil,
>I was looking into this section in your attachment:
> Internationalized Domain Names
>    * Internationalized Domain Names (IDNs) should be converted from 
>Punycode [RFC3492] into their UTF-8 string representations. So that, for
>      http://www.xn--exmple-jua.org/
>      becomes
>      http://www.ex蚓ple.org/.
>If you have
>It is not possible to decide whether it should become http://www.ex蚓
>pless.org/ or http://www.ex蚓ple゜.org/ since "ss" in the Punycode string 
>could have been originally "ss" or "゜".
>So I think this canonicalization step is not feasible. I'm also not sure if 
>it is necessary: If you get http://www.xn--exmpless-jua.org/ you could 
>process it in Powder just "as is", without trying to go to the 
>representation with non-ASCII characters. The same for http://www.ex蚓
>pless.org/ . But maybe I missing something?
>Just let me know what you think. Note that the problem of the 
>unidirectional relation between "゜" and "ss" is a problem of IDNs which 
>will soon be addressed by a proposed IETF Working Group, see 

#-#-#  Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University
#-#-#  http://www.sw.it.aoyama.ac.jp       mailto:duerst@it.aoyama.ac.jp     
Received on Thursday, 10 April 2008 10:45:36 UTC

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