my question is about security that is really forgotten in all available documents.
How to make securised an FLEX ! AIR application !
I wonder about data that cross the network clearly , sqlite offline databases that is easy to access; and the easy to decompile an swf.
Use the same techniques you would anywhere else. There are many encryption libraries available. Of course, the most secure platforms are handled through client-server sessions. Usability and security is usually a trade off.