PHP licese delivery script

Hi

Is there any free php serial key generator script available which will generate serial key based on paypal ipn

is there reason why you cant use own made script? like md5(paypal_ipn . rand()) ?

since php is free and open source I can't exactly see the point unless you zend or ioncube your scripts. If you do decide to do something like that however I suggest not only using the paypal ipn. store it in a database with a second field which would be something like md5(paypal_ipn.date('Y-m-d')); that way you can trace back what has happened and make sure everything is right.