[Flash8] AS2 and Decryption

programming flash
1

I am kind of new to AS and not sure how to decrypt a text file.

If I have a text file that is on my web server (which I need to be encrypted) and is used to retrieve variables for Dynamic Text fields. How do I decrypt the file and then take the variables and put them in the Dynamic Text fields?
What is the best method to make the files unreadable but can be decrypted by the flash file?

Currently I use this to get the variables and put them in Dynamic Text field but I want to add some kind of encryption to this.

myData2 = new LoadVars();
myData2.onLoad = function() {
	cat1con.htmlText = this.cat1con;
};
myData2.load("FLASH1PHP.php?cat=1");
stop();

So I will encrypt the FLASH1PHP.php file in some method but that needs to be able to be decrypted in flash and be able to put into a dynamic text field.
Is it possible?