Protection my paid extension

I wanna to know If i make an extension [Paid] How to protect it.
Some extension developer told me make it with email like take email from user and make online file.txt and make extension check if is email allowed to use it or not.
And see deep host extension he make this way.

my question: How to do this way? or is there is any another way to protect my extension or not?

Sorry if there are grammatical errors, my English is not very good

I can help you to protect your extensions being re-sell without your permission.
You can text me personally....

Simple answer is you can't protect your extension. It'll be pirated at the end.

no when i use Deephost or Jewel extensions, if the build email is not same,
then app will force a dialog that extension is not licensed and something like that.

that's a kind of protection where no one can use it on their own without buying it from extension developers

I know that is he can any one have .aix file can get source code but this step will be make hack extension more difficult, I think

yeah that is what i mean.