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MKL27Z644 Bootloader encryption

Question asked by Martin Dušek on Jan 21, 2020
Latest reply on Jan 27, 2020 by Mark Butcher


I built NXP_Kinetis_Bootloader_2_0_0\targets\MKL25Z4\kds\freedom_bootloader. It works fine. Now I would like to encrypt application image (the image that is received by this bootloader and flashed to the flash memory).


Please provide instructions:


1) How do I build this bootloader with decryption support?

2) How can I create encrypted application image?

3) How do we send encrypted application image to the device (via USB HID)?


I know my MCU doesn't have any hw crypto module, but I think I can use e.g. GitHub - kokke/tiny-AES-c: Small portable AES128/192/256 in C  to decrypt AES encrypted image in bootloader. Or is there already any small flash footprint library provided by NXP?


Is there any tutorial for this? Are there any sample projects (even for different MCUs)?