Where to store encrypted key of a prepulated sqlite in air application

I have an air mobile application which bundled with a sqlite database which is pre-populated and encrypted with a key. Now since someone can reverse engineer and get the key, I need to know if there is better place to hide it somewhere on the device which can only accessed by my application, els is not an option i guess, because it also expose the key.

The key has to be same so I cant generate it on the device.

It might have been asked previously but I dont see any relevant answer for storing the key.

Thanks