Hi all, I was working on a project where the embedded device can be updated online. To update the application one can connect the device to the serial port and then press(Update) and the application downloads the firmware from our website and uploads it to the device. Now this is unprotected update file where the code can be sniffed out and copies of the device will be made which is not in our interest. To prevent this i was wondering whether there was a method which could encode(scramble) the update file with a secret key and when downloaded into the device, the device itself decodes the update file back and the device works as should work. Is there any thoughts about how I can manage this? Im using Uvision3 and LPC935 microcontroller. any help is realy appreciated thanks, Khaled
thank you mike for the reply, I just wanted to know how to decrypt it back in the controller itself. Generating a secret key can be done with no problems, and the update host can even encrypt the data to be programmed but then the update host sends the encrypted data to the microcontroller and then I want the controller to decrypt it to the original hex code generated by the Compiler and program itself. Any example codes are really appreciated.