Encoders / DecodersLesson 21Free preview

Punycode Converter

This lesson is part of Web Developer Tools · All levels

Summary

Punycode is encoding that converts a domain label containing Unicode characters into an ASCII form, for example münchen.de to xn--mnchen-3ya.de. The xn-- prefix is needed for non-ASCII domain names to be processed by the DNS system that works with ASCII. The browser usually performs this conversion automatically when you type in an international domain. Beware because similar characters from different alphabets can be used for homograph attacks.

Key points

Changing the Unicode domain name label to ASCII
The resulting conversion domain is prefixed xn--
It takes DNS and old systems to process domain names
Not encryption, just domain name representation
Similar characters can be misused for homograph attacks

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