Interesting. From what I can tell though, the lack of support from those TLDs seems to be deliberate rather than due to any technical challenge (the domain you register ends up just looking like standard alphanumeric ASCII with some dashes). I may be wrong, but it probably requires more effort for a TLD to disallow IDNs as they'd have to implement a test to try and detect a punycode string within the ASCII.
The one technical challenge I suppose could be a concern would be optionally implementing some sort of test to detect domain registration attempts that use similar-looking characters to those in existing legitimate domains (e.g., registrations from scammers attempting phishing attacks with domains that look similar to other domains but use different extended characters).
Still, it feels like the lack of support from these TLDs is more a matter of policy than a technical challenge.
> The one technical challenge I suppose could be a concern would be optionally implementing some sort of test to detect domain registration attempts that use similar-looking characters to those in existing legitimate domains (e.g., registrations from scammers attempting phishing attacks with domains that look similar to other domains but use different extended characters).
The one technical challenge I suppose could be a concern would be optionally implementing some sort of test to detect domain registration attempts that use similar-looking characters to those in existing legitimate domains (e.g., registrations from scammers attempting phishing attacks with domains that look similar to other domains but use different extended characters).
Still, it feels like the lack of support from these TLDs is more a matter of policy than a technical challenge.