How do you protect a premium theme from being copied?

I'm thinking of doing up a couple of premium themes, and selling copies of them. I've never done anything like this before, so I have a couple of questions.

I appreciate that this is mainly a forum for asking technical questions, so if anyone wants to point me in the direction of somewhere that might be more appropriate for these questions, please let me know.

My main question is about copies of a theme. If I sell a copy of a premium theme, and the end result is that a person gets a zip file of my theme, is there any technical way to limit them to only using it in one installation of WordPress? Or do I just rely on the goodness of their hearts?

Also, a related question: What kind of license, if any, should I include with a premium theme?

Thanks.

Topic ziparchive theme-development licensing themes Wordpress

Category Web

1
answered at

I've always thought that if you were going to do multiple themes and generally use some of the same concepts create a Master Theme and GPL and then do child themes that take advantage of the Master Theme, but primarily include CSS for styling the Master Theme.

This should provide you with the GPL theme framework upon which the Wordpress community could be happy as well as Licensable theme from a styling point-of-view.

An intellectual property lawyer would have to tell me if I'm wrong, but I think this would provide you with a solid foundation for a licensable product. From their you could do what Toscho said about keys.

Another idea that I have had, but am not technical enough to know if it could work is to create external CSS on my site and block all other sites by default. Then when someone purchases the site - provide that domain access to hit the site and load the CSS.

1
answered at

There is no way to prevent the free distribution of your theme. You could make it harder by selling a copy that is restricted to a license key and a salted hash of the domain. But even if you put the code for this in a pre-compiled script it will be possible to get around it.

Sell support, upgrades and reliability, not the naked code.

For the license: PHP code which is uses WordPress functions and hooks is GPL per default by some peoples interpretation.
For your stylesheets, images and standalone PHP code you can use a different license.

About

Geeks Mental is a community that publishes articles and tutorials about Web, Android, Data Science, new techniques and Linux security.