SC-51 - Hardware-based Protection

a. Employ hardware-based, write-protect for [Assignment: organization-defined system firmware components]; and b. Implement specific procedures for [Assignment: organization-defined authorized individuals] to manually disable hardware write-protect for firmware modifications and re-enable the write-protect prior to returning to operational mode.


ID: SC-51
Enhancements: 

Space Segment Guidance

Hardware-based protection for space systems goes beyond simple software checks, integrating security directly into the spacecraft’s physical components or chips. Examples include secure boot mechanisms that cryptographically verify firmware images at power-up, tamper-resistant modules for cryptographic key storage, and physically isolated coprocessors for running high-assurance functions like attitude control. These hardware constructs reduce the risk of advanced attacks that bypass software-only defenses—e.g., by modifying memory at the hardware level or installing malicious firmware. In practice, design teams may adopt specialized microcontrollers or field-programmable gate arrays (FPGAs) with embedded security features. During assembly and testing, strict chain-of-custody protocols and “golden master” checks guard against the introduction of compromised parts. Ultimately, hardware-based defenses form the lowest-level root of trust, giving mission planners confidence that critical security properties hold even if higher-level software layers become compromised or corrupted.