Hi, I would also like a secure registry plugin.
For a non-premium server, I tested the plugins already by the hour and they have problems because some users can register with ex: minecraft username and after if someone comes with Minecraft as username they let him log in. That is a bigger character and you can already steal a player’s identity.
While I personally don’t like the nature of non-premium servers, there are plugins like „auth. me“ which requires people to enter a password when they log into your server. Maybe worth looking into.