RFC - 3492

Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA)

Original:	ftp://ftp.isi.edu/in-notes/rfc3492.txt
Authors:	A. Costello [Univ. of California, Berkeley]
Date:	March 2003
Category:	Proposed Standard

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Referred by:	11 RFC
Refers to:	7 RFC

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Status

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

Punycode is a simple and efficient transfer encoding syntax designed for use with Internationalized Domain Names in Applications (IDNA). It uniquely and reversibly transforms a Unicode string into an ASCII string. ASCII characters in the Unicode string are represented literally, and non-ASCII characters are represented by ASCII characters that are allowed in host name labels (letters, digits, and hyphens). This document defines a general algorithm called Bootstring that allows a string of basic code points to uniquely represent any string of code points drawn from a larger set. Punycode is an instance of Bootstring that uses particular parameter values specified by this document, appropriate for IDNA.

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