[Cryptography] Bloom filter question

[Michael Kjörling]

On 4 Aug 2025 13:14 -0400, from johnl at iecc.com (John Levine):
>> If you can apply this after some normalization of the addresses -
>> e.g., fixing the case after the “@“ - so much the better in making
>> attacks even less plausible.
> 
> Right. For ASCII addresses we'll probably put them in all lower case. For UTF-8
> addresses, normalization is a huge can of worms (case folding is language and
> country dependent, among other things) but we can burn that bridge when we get
> to it.

Just use the Punycode encoding of the required domain name label(s) as
the input if there are any IDN characters in the FQDN. That's how
internationalized domain names are represented in DNS anyway, and DNS
is already case-insensitive.

No need to reinvent the wheel there.

-- 
Michael Kjörling
🔗 https://michael.kjorling.se