FortBoot: Fortifying Rooted-in-Device-Specific Security Through Secure Booting

With the complex System-on-Chip (SoC) architectures ever-increasingly used in security-critical applications, realizing a secure boot procedure is of at-most importance, in which the integrity and authenticity of the firmware (FW) on hardware (HW), as well as the trustworthiness of the software (SW), will be verified. Considering the complexity of the existing solutions and their vulnerability to emerging attacks, in this paper, we propose FortBoot, which is a comprehensive framework to strengthen secure boot using an integration of (1) dynamic key generation for unique randomness against brute-force and guessing attacks; (2) Mutual FW-HW binding for restricting unauthorized and malicious FW load/execution; (3) anti-rollback measures for preventing the use of (maliciously) flawed/downgraded/altered FW to be loaded/executed on unauthorized HW; and (4) dynamic code attestation for providing real-time code integrity confirmation. To show its effectiveness, FortBoot is implemented on OpenTitan SoC, whose comprehensive security assessment verifies its resistance against a wide range of advanced attacks.