Flex Rest Security

Hello,
I am trying to grasp how people have best solved the integration of
FLEX
Rest services and restful_authentication. Since FLEX is stateful, how
are
you securing the access to the web services? For example, once the Flex
app
calls the login method, returns success, how does the rails app know the
user is authenticated when a request for /CONTROLLER/index comes in? I
dont
believe Flex uses sessions so I assume there is another mechanism here.

Thanks
Adam