I just found a open source project called PHP Application Distribution Licensing System. But it's licensed under GPL, can I use it for a commercial software which has to be protected by a license? I also need advices about the security, performance etc. Would it get cracked easily by looking into the source code of PADL, or overlading the server by executing the key testing code on every pageviews? Here is the project: http://freshmeat.net/projects/padl/ http://www.phpclasses.org/browse/package/2298.html Thanks
Actually, it's under LGPL. (Lesser General public license) Here's a part of it: http://www.gnu.org/licenses/lgpl.html If that's unclear, you could try to contact the developer, and tell him what exactly you want to do, and if that's okay.
AFAIK, GPL allows commercial use anyway, provided you include information on how to get the un/modified source code. Performance: not an issue, you can always take out the checks on every request anyway and only "call" for validation by checking the output of the PHP script that outputs an encrypted version of the license. Security: while it could be nullified so that the user can use the script, you can determine if it is an invalid version by calling it from the script that checks from "home". Of course, this involves finding the site. You could maintain a list of servers using the script and check installed versions and where they are installed against your list, maybe through an automated crawler of a Google search for terms unique to the script. With IPB's similar system, I've heard one or two point out nulled versions so you can also rely on people reporting sites.