Nameprep
Encyclopedia
Nameprep is the process of case-folding to lowercase and removal of some generally invisible code points before it is suitable to represent a domain name
, or other such canonical name. It is used by IDNA, using the Unicode
standard for NFKC normalization.
Nameprep is defined in RFC 3491, "Nameprep: A Stringprep Profile for Internationalized Domain Names (IDN)", as a profile of Stringprep, which is described in RFC 3454, "Preparation of Internationalized Strings ("stringprep")."
It does not map lookalike characters to a single character nor prohibit the use of lookalike characters. There are good reasons for this, such as the fact that fonts differ in which characters are lookalikes, and the fact that any decision on which character to map to will obviously provide a bias towards users of one script, but it has potentially grave implications for security if not considered by the designers and administrators of systems based on nameprep (the best known example of this being VeriSign's handling of IDNA names in .com and .net).
Domain name
A domain name is an identification string that defines a realm of administrative autonomy, authority, or control in the Internet. Domain names are formed by the rules and procedures of the Domain Name System ....
, or other such canonical name. It is used by IDNA, using the Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
standard for NFKC normalization.
Nameprep is defined in RFC 3491, "Nameprep: A Stringprep Profile for Internationalized Domain Names (IDN)", as a profile of Stringprep, which is described in RFC 3454, "Preparation of Internationalized Strings ("stringprep")."
It does not map lookalike characters to a single character nor prohibit the use of lookalike characters. There are good reasons for this, such as the fact that fonts differ in which characters are lookalikes, and the fact that any decision on which character to map to will obviously provide a bias towards users of one script, but it has potentially grave implications for security if not considered by the designers and administrators of systems based on nameprep (the best known example of this being VeriSign's handling of IDNA names in .com and .net).
See also
- InternationalizationInternationalizationIn economics, internationalization has been viewed as a process of increasing involvement of enterprises in international markets, although there is no agreed definition of internationalization or international entrepreneurship...
- International Components for UnicodeInternational Components for UnicodeInternational Components for Unicode is an open source project of mature C/C++ and Java libraries for Unicode support, software internationalization and software globalization. ICU is widely portable to many operating systems and environments. It gives applications the same results on all...
(ICU contains an implementation of Nameprep)