What is meant by 'safety-related hardware' and how is it protected from tampering?

• A. Hardware whose failure could compromise safety; protected via physical security, code signing, change control, and independent verification.
• B. Software-only components that do not affect safety.
• C. Non-safety-related hardware with no protection.
• D. Any hardware used in safety systems with no tamper protection.

Answer: (C)

Safety-related hardware refers to components whose failure or tampering could create a safety hazard in operation. Because of that, it is protected with multiple layers to prevent unauthorized access and changes: strong physical security to restrict who can reach the hardware, tamper-evident measures to reveal any interference, and a secured supply chain and installation process. Firmware and software running on this hardware are safeguarded through code signing to ensure only approved, trusted software is executed, and through formal change control with independent verification to ensure every modification is reviewed, approved, and validated before it is put into service. This combination helps detect and prevent unauthorized modifications and keeps the hardware operating as intended under all conditions. Descriptions that refer to software-only components, non-safety hardware without protection, or any hardware in safety systems without tamper protection miss these essential protections and can’t adequately describe safety-related hardware.