From: "Werner Soekoe" > Jon, > > Even if the code could be ripped of a microcontroller, implementing a > public/private key encryption would render the code useless, especially if > the PIC is assigned a new public key for every new transmission. Or am I > wrong at assuming this? I suppose the application has a lot to do with how successful you will be in implementing good security. For example, if the physical location of the pic is secure, then it would be safer to store the public key in the pic, than risk a man in the middle type attack as Ashley said. If the pic is accessible and I can read the code, I would be able to duplicate its function so that the PC end could not tell any difference, but also add extra functions to transmit the data before it got transmitted. Im sure there's lots of other scenarios, but the way you solve the problem really depends on your application, the location of the parts, and the reason you are encrypting the data. Jon Baker -- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.