nRF54L15 firmware encryption

[fredly]

Enable the "mcuboot_with_encryption" function. 1: When using VSCode for flashing, by default, mcuboot is flashed with un-signed and un-encrypted firmware, while the application firmware is flashed with signed firmware. Can signed and encrypted firmware be flashed? 2: Does the mcuboot image file support encryption functionality?

[Nishant Gaurav]

Hi, fredly

When you build with encryption enabled, the build system generates both zephyr.signed.bin (unencrypted, signed) and zephyr.signed.encrypted.bin (signed and encrypted) in the application build directory. 

To enable encryption, you build with:

 west build -b nrf54l15dk/nrf54l15/cpuapp -- -DSB_CONFIG_BOOTLOADER_MCUBOOT=y -DSB_CONFIG_BOOT_ENCRYPTION=y

The MCUboot bootloader image itself is not encrypted — it is the application image that gets encrypted. MCUboot is the entity that performs decryption of the application image during the slot-swap process.