Contact Afilias

Get in touch with Afilias.

What are the "restricted characters" used by Punycode?

Punycode uses only restricted ASCII characters and numbers (A-z, 0-9) and the hyphen (-). The Punycode schema and the standardization which specifies IDN wire-format to remain in the restricted ASCII repertoire was based on the following advantages:

  • Language independent
  • Superior in compression
  • Compact in code size
  • Round-trip safe
  • Superior for encoding Chinese/Japanese/Korean characters. (over other ACE schemes evaluated at that time)