i wana little bit help about url encryption(md5) or any other ecryption i have two files

1: index.php
2: premium.php

i want to access premium.php with url encryption like md5 or any other encryption with in index.php via iframe or any other method. if user directly access the premium.php file the message will show to user "Access Denied!". user can access premium.php via index.php directly without username and password . mean index.php show the data of premium.php in encryption format and url of premium.php in the index.php file also encrypted user cannot copy my link hope you understand and help me thank you so much