Editing Punycode (section)

{{Short description|Encoding for Unicode domain names}}
'''Punycode''' is a representation of [[Unicode]] with the limited [[ASCII]] character subset used for Internet [[hostname]]s. Using Punycode, host names containing Unicode characters are transcoded to a subset of ASCII consisting of letters, digits, and hyphens, which is called the letter–digit–hyphen (LDH) subset. For example, the [[German language|German]] ''[[München]]'' ([[English language|English]]: [[Munich]]) is encoded as ''Mnchen-3ya''.

While the [[Domain Name System]] (DNS) technically supports arbitrary sequences of octets in domain name labels, the DNS standards recommend the use of the LDH subset of ASCII conventionally used for host names, and require that string comparisons between DNS domain names should be case-insensitive. The Punycode syntax is a method of encoding strings containing Unicode characters, such as [[internationalized domain name]]s (IDNA), into the LDH subset of ASCII favored by DNS. It is specified in [[IETF]] [[Request for Comments]] 3492.<ref name="rfc3492">RFC [https://datatracker.ietf.org/doc/html/rfc3492 3492], ''Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDN)'', A. Costello, The Internet Society (March 2003)</ref>