Posted on May 30, 2011 at 03:52It's in ROM so it might be a tad hard to rewrite/replace, and it's pretty tightly packed in 2KB. I have an annotated listing of the 103 boot rom. The Readout Protection is enforced, so your code is protected from your casual user.
As I recall some of the ST DFU loaders use AES
My general recommendation would be to write something simple, based on the XMODEM, or family of protocols. Simple and robust.
Not sure what encryption you have in mind, or if it is worth the effort. Without a strong end-to-end chain of protection, most of these things are breakable, or built broken. What's to stop someone extracting firmware from the die?
