In classic ASP there is no any encrypt function. But you can use this useful source code to encrypt any string data using MD5. MD5 encryption is a one-way hashing algorithm. MD5 is a great advantage because it is speed and easy to use.
This digs for your PRIVATE information such as your IP behind your firewall. This article is a harmless way to perform a leaktest that could give someone access to your private information.
This simple tutorial is intented to learn you how it is possible to prohibit access to certain page. A technique is to check the referrer of the visitor : if he come from a page of your web site let him in, else display a default message ...