Authenticating Java FX application

Hi all,

I am creating a free game in java FX and I would like to offer some advanced features for the supporters (a user of the application that donates to support the project).

But I dont know how to authenticate the user to some network service.
i would like to have a hosted application (or light framework) accessible through the network so the user can do something like login with posting credentials (email, password and maybe his IP adress - so I can check if he has passed his credentials to someone else) and to be able to manage the service to add, remove, (un)block users.

I dont know if I should try to create an authentication app myself, as it seams it shouldnt be as hard as I have no roles, no authorization, just a simple authentication. I would like to host it somewhere for free, than maybe if it will be succesful a want to have my own paid light hosting.

I looked for some frameworks, like Apache Shiro, but i would like to know what are the approaches in this kind of donating user authentication, before dwelling into some framework for months just to realize that it is not what I want.

My another google skills took me only to spring security (seems to me heavy for this) or some guides how to secure the application itself (thats not my case).

Could you suggest me some approach or point me to some up-to-date overview blogs/articles? I dont want to be security specialist just to do this simple task. Thank you.