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Letter from Paul Twomey to Edward Viltz

Los Angeles, 21 October 2003

Mr. Edward G. Viltz
President and CEO
Public Interest Registry

Dear Mr. Viltz,

On behalf of ICANN, I am honored to authorize Public Interest Registry to deploy Internationalized Domain Names (IDNs) on the basis of its commitment to adhere to the "Guidelines for the Implementation of Internationalized Domain Names, Version 1.0". In working so diligently to achieve consensus on these Guidelines with other key IDN registries, Public Interest Registry has demonstrated its leadership in helping to achieve practical solutions to the many technical and operational challenges that IDN deployment poses.

Public Interest Registry leadership is a model of promoting the coordination of the domain-name system in the public interest, which is a vital aspect of missions of both ICANN and Public Interest Registry

Accordingly, on behalf of ICANN and acting under ICANN Board resolution 03.48, Public Interest Registry is hereby granted written approval for the deployment of IDNs in compliance with the provisions of the "Guidelines for the Implementation of Internationalized Domain Names, Version 1.0", including by using tagged domain names beginning with "xn--" as specified in Appendix K of the Registry Agreement between Public Interest Registry and ICANN.

ICANN looks forward to supporting the efforts of Public Interest Registry and others to promote the responsible deployment of IDNs based on the principles stated in the Guidelines.

Best regards,

Paul D. Twomey
President and CEO
Internet Corporation for Assigned Names and Numbers

Domain Name System
Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as"""" is not an IDN."