Hi Bert,

One possible scheme, which I use in one of my own products, is to use a simple cyclic XNOR encryption with an n-byte key. This is basically the same method used to protect the contents of the internal memory in the original 8051 and can be easily decoded by your custom bootloader.
Although Jez will probably object and say that his hamster could crack this in a few hours ;o), it does provide the proper kind of 'barrier' to your client(s).


Rob.