Ok, I am in the process of creating a cms. There will be a free version, and a premium version. Obviously the premium version will have modules and such that the free version does not have. Does anyone have an idea on how i can prevent my premium version from being shared across the web? Ive looked into using a license key with remote server validation, as well as encrytion, and encoding the premium scripts. I dont want to use Zend Guard or Ioncube, because i dont want users to have to have that software installed just to ues the cms. I also want the cms to be customizable which rules out encoding. Anyone have ideas to prevent the scripts from being nulled? If its possible to maybe just encode a single page that does remote validation… just something… It doesnt have to be a bullet proof thing.. but something that prevents novice crackers from nulling it and releasing it
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ENCODING PAGES:
Personally, I have tried a few techniques to avoid PHP encoders but nothing was really effective in a commercial environment.
Based on my experience though, I wouldn’t worry so much about Ioncube and Zend not being installed on servers because most managed environments will most likely already have both, this is what I have found anyway. Because of this it reduces the problem of users to have to install it for a single application.
In saying that it depends on your target market also, if you’re going head-to-head with the likes of Joomla! or WordPress for example, then your target market typically uses a managed environment so no big issue.
If you’re however going for say an intranet market this could be a minor problem but any server admin worth a grain of salt will be able to install this easily without fuss, they will also understand why you put it in place. Note, the intranet market is a bit harder as you will need to specify port settings to check the license in your licensing module.
SIDE NOTE: As your product is going to be distributed with source code available you do need to be careful and pay attention to your Intellectual Property (IP), this generally means putting a legal disclaimer on every page that is readable. Also, don’t forget to respect the requirements of other IP owners scripts you may be using in your project.
LICENSING & ENCODING (THE SUGGESTION):
Encoding a single page with licensing functions is a way of going about it but you will find it fairly easy to bypass if the rest of the source code is available.
What I would look at is encoding a single page with licensing functions but also encoding your login validation, half of your authentication checks for each protected page and some basic functions for posting to the database also. This way if they try to remove your encoded page with the licensing script there is no login or updating of content – plus they will get kicked out of the system as only half of your session checking will be valid – I hide a kill function nested into another function that is required for each page to operate, this may be a menu (this is great because you can hide the function with the logout), it just looks like part of the log-out function but in reality it is a function to destroy the session if not all variables are present.
When choosing values for your authentication checks on each protected page (that function should be encoded), try using what appears to be a random variable and non-descriptive names then encode the variable (I like MD5 hashes for this). It is another way to give more security around the ‘hacking’ of your script.
I hope this may help you and sorry that I cannot recommend a better solution.