#Secured Firmware
To secure a firmware using a crypto processor:
- Use a trusted processor and tamper-resistant storage to store the firmware image encrypted with a private key.
- Store the bootloader unencrypted in the tamper-resistant storage e.g. ROM.
- Hard-code the public key needed to load and verify the firmware into the bootloader.
- Load, decrypt, and verify the firmware image by the bootloader.
Any other image not signed by the original manufacturer won’t be loaded by the bootloader. Public key cannot be changed on ROM.
CPU