On the Subject of Feed Identities; I propose the following:

1. Generate a Private/Public ED25519 key pair
   
2. Use this key pair to sign your Twtxt feed
   
3. Use it as your feed’s identity in place of # url = as # key = ...
   

For example:

$ ssh-keygen -f prologic@twtxt.net
$ ssh-keygen -Y sign -n prologic@twtxt.net -f prologic@twtxt.net twtxt.txt

And your feed would looke like:

# nick        = prologic
# key         = SHA256:23OiSfuPC4zT0lVh1Y+XKh+KjP59brhZfxFHIYZkbZs
# sig         = twtxt.txt.sig
# prev        = j6bmlgq twtxt.txt/1
# avatar      = https://twtxt.net/user/prologic/avatar#gdoicerjkh3nynyxnxawwwkearr4qllkoevtwb3req4hojx5z43q
# description = "Problems are Solved by Method" 🇦🇺👨‍💻👨‍🦯🏹♔ 🏓⚯ 👨‍👩‍👧‍👧🛥 -- James Mills (operator of twtxt.net / creator of Yarn.social 🧶)

2024-06-14T18:22:17Z	(#nef6byq) @<bender https://twtxt.net/user/bender/twtxt.txt>  Hehe thanks! 😅 Still gotta sort out some other bugs, but that's tomorrows job 🤞
...

Twt Hash extension would change of course to use a feed’s ED25519 public key fingerprint.