There are a lot of questions about how to implement Licensing in Flex and AIR.
I cannot explain you 100% how it works but below is list of libraries/functions for my solution.
- codegenas3 – AS3 library for generating system/machine id.
- as3crypto – AS3 library for encryption/decryption.
- Local Shared Object – AS3 Class for storing license information (similar to Windows Registry).
- Mcrypt – PHP functions for encryption/decryption.

