Proposed Charter for the IDNAbis Working Group

Vint Cerf vint at
Wed Mar 26 14:42:03 CET 2008

I expect that the discussions will be wide ranging though some topics may not result in WG output but perhaps some internet vdrafts of note. V

----- Original Message -----
From: Simon Josefsson <simon at>
To: Vint Cerf
Cc: idna-update at <idna-update at>
Sent: Wed Mar 26 06:31:15 2008
Subject: Re: Proposed Charter for the IDNAbis Working Group

This works for me, and is substantially better than earlier versions.

I hope that discussions that compare the cost of changing the prefix
with the cost of making backwards incompatible changes will not be
declared out of scope with reference to the charter.  It is important to
be able to make that comparison in order to produce good text that will
help implementers plan transition strategies.  The discussions so far
suggests that those discussions will be permitted, and that is


Vint Cerf <vint at> writes:

> Ladies and gentlemen,
> on the basis of the several weeks of exchanges on this list, a draft
> charter for the IDNAbis Working Group has emerged. It is enclosed
> below and as the proposed chair, I ask the participants in the IDNA- 
> update distribution list to confirm adoption of the charter. If there
> are no strong objections, I request that Area Directors Lisa
> Dusseault and Chris Newman put the charter forward to the IESG for
> its approval. Needless to say, I am grateful to all of you who have
> contributed to the production of this charter in the past several
> weeks, most particularly john klensin, paul hoffman, martin duerst,
> patrik fältström, mark davis, harald alvestrand, stephane bortzmeyer,
> erik van der poel, jefsey morfin, simon josefsson, lisa dusseault,
> among many others. Apologies if I missed adding your name to the list
> - it was starting to get kind of long.
> I look forward to what I hope will be rapid progress of this working
> group towards the production of RFCs documenting improvements to the
> IDNA protocols.
> Vint Cerf
> -------------
> IDNABIS Charter
> Chair(s):  Vinton G. Cerf
> Applications Area Directors:
> Lisa Dusseault (ldusseault at
> Chris Newman (Chris.Newman at
> Applications Area Advisor:
> Lisa Dusseault (ldusseault at
> Mailing List:
> General Discussion: idna-update at
> To Subscribe:
> Archive:
> Description:
> The original Internationalized Domain Name (IDN) WG set the
> requirements for international characters in domain names in
> RFC3490, RFC3491 and RFC3492 in 2002 (published in 2003).
> These documents depend on RFC 3454 and were tied to Unicode
> version 3.2.  An update to the current version (5.x) is
> required to accommodate additional scripts.  In addition,
> experience has shown a number of real or perceived defects or
> inadequacies with the protocol.
> This WG is chartered to untie IDNA from specific versions of
> Unicode using algorithms that define validity based on Unicode
> properties.  It is recognized that some explicit exceptions may
> be necessary in any case, but attempts would be made to
> minimize these exceptions.
> Additional goals:
>   - Separate requirements for valid IDNs at registration time
>     (insertion of names into DNS zone files), vs. at resolution
> 	time (looking up those names)
>   - Review, and, as necessary revise, the algorithms and rules
>     for handling right to left character sequences in an IDN
> 	context to allow labels based on additional scripts and
> 	languages and to make presentation as predictable as
> 	reasonably possible.
>   - Permit effective use of some scripts that were
> 	inadvertently excluded by the original protocols.
>   - Ensure practical stability of validity algorithms for
>     IDNs.
> The constraints of the original IDN WG still apply to IDNABIS,
> namely to avoid disturbing the current use and operation of the
> domain name system, and for the DNS to continue to allow any
> system to resolve any domain name in a consistent way. The
> basic approach of the original IDN work will be maintained --
> substantially new protocols or mechanisms are not in scope.  In
> particular, IDNs continue to use the "xn--" prefix and the same
> ASCII-compatible encoding, and the bidirectional algorithm
> follows the same basic design.
> The work is initially organized as four documents: overview and
> rationale, protocol, table algorithm, and changes to the
> bidirectional algorithm. These documents are to be used as the basis
> for the discussion of the general direction of the work.
> This working group will be providing extended public review of
> the output of a design team that has been working on the issues
> described below. This review-based approach is being used in
> part because of the way the work was undertaken by the team; in
> particular, the design team has been working with IETF
> visibility and has solicited and received significant amounts
> of technical review already.  If the public review provided by
> this Working Group confirms the basic method outlined in the
> input documents, it is expected that the working group will be
> able to provide any needed changes and close in a short period
> of time.  If technical issues arise that indicate a
> fundamentally different approach must be taken, it is
> anticipated that this working group would close, and a new one
> with an appropriate charter would be considered.
> This work will address stable and unambiguous IDN identifiers.
> There are a variety of unsolvable problems, notably the problem
> of characters that are confusingly similar in appearance (often
> known as the "phishing" problem) that are not part of the scope
> of the WG.
> While it is referenced from the original IDNA package, the
> original Stringprep specification, RFC 3454, is not formally
> part of the IDNA package and will not be altered by this work.
> The work will update or obsolete RFC 3490.  It is not expected
> to continue to use Nameprep (RFC 3491).  Nameprep is used by
> other specifications; determining how (or whether) to update
> those specifications and, consequently, the long-term status of
> Nameprep, are not part of this effort.  The method for
> ASCII-compatible ("ACE") encoding of IDNs, "Punycode" (RFC
> 3492) will not be revised by this WG.
> Subject to the more general constraints described above, the WG
> is permitted to consider changes that are not strictly
> backwards-compatible.  For any such change that is recommended, it
> is expected to document the reasons for the change, the
> characters affected, and possible transition strategies.
> The assumptions outlined above are considered critical to the
> WG constituted this charter.  The WG will stop, close, and
> recommend that a new charter be generated if it concludes that
> any of the following are necessary to meet its goals:
>    (i) A change to the "punycode" algorithm or to the ACE
>    approach to encoding names in the DNS.
>    (ii) A change to the ACE prefix from "xn--"
>    (iii) A change to the basic approach taken in the design
>    team documents (Namely: a protocol that is independent of Unicode
>    versions, that removes any character mapping in the
>    protocol, and that has improvements to the bidi algorithm).
> Goals and milestones:
> Apr 08: WG formation
> May 08: Decision on form and structure of the WG document set
> Sep 08: WG Last Call on WG document set
> Nov 08: IETF Last Call on WG document set
> Documents:
> ---------------------

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