Domain name based license protection

[phparion]

Hi

i have made a web software that i will sell on different clients. Sale rule is that "One license for One domain"..so i want to place a check on domain name, i mean, if someone buys it for www.hisname1.com then he can only and only install and use it on www.hisname1.com and not anyother domain, if the domain name differes it should give him error that buy another license for different domain name.

i am thinking to place a check on domain name in index.php page so when the software will start it will check the domain name and will take decision based on domain BUT, if a user is clever he can change these lines or remove this check from index page. well, if i even encrypt it then how can i make sure user will not delete this code from index page? is there any way so that i can place two checks,

1 - domain name doesnt change?
2 - nobody deletes the code checking domain name?

please share your ideas better if with code too .

thanks in advance

[Anyango]

Probably encryption is the best way to protect source code of your web-based applications. i am not sure even if there is 1 another way to do so. one cant protect web based source code without encrypting it, as far as i know and i might be totally wrong. And if you encrypt your whole source file, how will your Client know which code line to delete to remove the Domain Check?

will be one heck of a challange for em

[phparion]

well, it has been done with pure php, i wish if i could paste the exact company name here, but if u can guess, they sell php scripts like newsletters, guest books, counters etc and when they give you zip package they ask you the domain name where you willl use it, and then do something with that so in their index.php page there is some encrypted code, that checks the domain name, i work for a company that bought some scripts fro this company, when i tried to install the script on seperate domain it gave errors to me for license and also when i removed the encrypted code it gave error that ILLEGAL MODIFICATIONS and there was no way for me to install it myself on different domain.

[Anyango]

That illegal modification thingy is easy. you just put in some encrypted code to check Filesize of your source file and compare it with original filesize when installed. if it differs, its been modified.

[jatar_k]

you could always look at something like this

[zend.com...]

[phparion]

how about storing some information on my own server and check every 24 hours the domain name? if u have used AMSN it does check for updates like this.

any idea about this?

[Anyango]

I thought about that, but you see, if the user has come down to deleting some code lines he could delete those lines of code too where you will check your server for information.

[Dinkar]

Divide your software in 2 parts. First part will have all necessary functions and will stay on your server. The second part will be the code to call those functions and do related things. Distribute this 2nd part.

[phparion]

i have uploaded the database connection files and some other necessary pages on my own server. so when the software starts it redirects to my server page there i perform the domain name check if ok then i allow it to access the connection and other files otherwise no. so even if someone deletes the encrypted code he will never be able to access these files on my server and wil get errors and errors throughout software :)