Secure login w. flash

Hi,

I am trying to write a secure login using flash.

I worked out that the login must be separate from the protected content otherwise a decompiler will get round it very quickly.

At the moment I have a login swf that posts variables to a server side script which then creates a session for a valid user.

The idea is to then forward on to the protected content. However I am unsure how to pass the users info to the swf so a user could not modify before the swf gets it and thus see another members content or what I can do to stop someone just accessing the content directly by just knowing the swf file’s location.

Thanks in advance

ash