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Difficulty: HardHardware and Embedded Systems Security

An defense contractor is engineering autonomous marine surveying submersibles deployed in untrusted oceanic regions. The vehicle onboard processing unit must generate device-unique cryptographic keys for encrypting collected telemetry. To resist sophisticated physical tamper attacks—such as silicon chip decapsulation, focused ion beam microprobing, and non-volatile memory readout if a submersible is captured—the keying material must not exist as stored digital bits anywhere on physical media when powered off. Which hardware security technology should be implemented to meet this requirement?

  1. A Physically Unclonable Function (PUF) embedded within the system-on-chip siliconAnswer
  2. B
    A discrete Trusted Platform Module (TPM 2.0) chip soldered to the motherboard bus
  3. C
    A high-performance central Hardware Security Module (HSM) accessed via encrypted network tunnels
  4. D
    A software-based Trusted Execution Environment (TEE) provisioned in the host hypervisor

Answer

A Physically Unclonable Function (PUF) embedded within the system-on-chip silicon
A Physically Unclonable Function (PUF) leverages microscopic physical variations inherent in semiconductor manufacturing to generate unique cryptographic keys on demand. Because the key is derived dynamically from physical silicon properties rather than stored as persistent binary data in non-volatile memory, an attacker cannot extract key material even when performing physical chip decapsulation or direct microprobing.

Step-by-Step Solution

1
Analyze the threat model and physical constraints presented in the scenario.
The device operates autonomously without network access and faces physical capture, including physical silicon decapsulation and microprobing threats.
Understanding the physical attack vector dictates whether logical, discrete, or silicon-level key generation controls are required.
2
Evaluate key storage mechanics across candidate hardware components.
TPMs, TEEs, and standard non-volatile storage rely on persistent binary representations of keys, whereas a PUF derives keys dynamically from silicon manufacturing variations.
If keys are never stored as binary states in flash memory, physical memory extraction and decapsulation attacks cannot yield the key material.
3
Select the hardware mechanism that satisfies both offline operation and anti-decapsulation physical security.
The Physically Unclonable Function (PUF) fulfills all physical anti-tamper and dynamic key generation requirements.
PUF acts as a digital fingerprint of the silicon chip, synthesizing cryptographic keys only during runtime.

Key Concept

Physically Unclonable Functions (PUF) and Hardware Root of Trust Anti-Tamper Mechanisms
Estimated Time:2m 0s
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Topics

Hardware and Embedded Systems Security

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