Punycode encoding/decoding

1. Punycode is an encoding system primarily used to convert domain names from Unicode format to ASCII.

2. Punycode-encoded strings contain only ASCII characters, ensuring compatibility with existing systems.

3. Punycode encoding is reversible, meaning strings encoded using Punycode can be decoded back to their original non-ASCII strings.

4. Security was taken into account in the design of Punycode to prevent certain types of encoding attacks.

5. Since the Domain Name System (DNS) only supports ASCII characters during resolution, Punycode encoding was developed to address this need.