How can i secure my custom indicator like this?

hello friends, i am an average trader. i have a forex product that i am selling. Now, how can i create a plugin for my custom indicator file, that will be used on mt4 so that it can only be accessed through generated password, and i can also do free trial.
the point is that if my customers are not interested again, they can opt out without having access to my plugin again. any tutorial site will be ok. I just dont want my product to be copied and later returned for refund.. i have seen it on many sites.
When you re out, you are deactivated immediately. thanks.

To protect you product is better to have server based license. In my opinion any passwords can be hacked very easy.

Server mean that you have a data base of owners on your server and track the database. So you will be able to add and remove users.


This way of protection also can be hacked but much more harder.

P.S Everything what is locked can be opened. Only question - how bad you want to open it.

thank you sir. i will work towards that