AS3 Flash Protection + Secure Server Communication

I need my Flash client for reliable communication with the server (via binary sockets). To do this, I was thinking of embedding a pre-shared key inside the AS3 code and exchanging XORed data using a custom protocol.

I was told that SWF decompilers do a great job of making all the built-in codes clear and understandable. Does this mean that I cannot hide my key?

If this method is not practical, what other options are there? I tried as3crypto, but found that it contains flaws and does not have serious documentation.