Protecting remote CFCs from unauthorized access

["SEJ-69" <webforumsuser@xxxxxxxxxxxxxx>]

Now that I'm working with Flex I've discovered that I no longer have session 
variables to maintain access to a site.  How do I protect my Coldfusion CFC's 
from unauthorized access?

 I'm working on a site that requires user authentication.  While the actual 
user authentication in flex is easy, this doesn't protect my Coldfusion CFCs 
from someone that knows how to hook up directly to my site which would bypass 
the interface security.

 I'm also coding an Adobe Air application to go along with the website. 

 TIA.