English
Menu

Hardware Security: Advanced Topics and Trends

Which correctly describes the mechanism of DICE (Device Identifier Composition Engine) defined by the TCG?

  1. AThe same secret value is placed in every device, and even when firmware is updated and changes, the same key as at manufacturing continues to be used forever
  2. BA new key is downloaded from a server over the network at every boot, and the device is made to hold no secret value at all
  3. CEach layer's secret is derived from the device-unique secret and the measurement of the next layer's firmware, and each layer makes its own secret unreadable before moving on
Show answer and explanation

Answer: C. Each layer's secret is derived from the device-unique secret and the measurement of the next layer's firmware, and each layer makes its own secret unreadable before moving on

In DICE, the small piece of hardware or ROM code that runs right after power-on derives a secret called the CDI with a one-way function from the device-unique secret (UDS) and the hash of the firmware that runs first. That firmware in turn uses the measurement of the next layer to derive the next layer's CDI and erases its own CDI before handing over control. If firmware is rewritten, the derived secrets change, so tampered firmware cannot claim the correct key, and even if a later layer is taken over, the secrets of earlier layers do not leak. Device identity and attestation can be realized with little hardware even on small microcontrollers without a TPM.

  • A. Because keys are derived from per-device secrets and measurements, they differ per device and per firmware.
  • B. The secret is derived inside the device; it is not received from a server each time.
  • C. Correct. Each layer derives secrets from measurements and hides its own secret from the next layer.
Practice this topic Back to topic

Books on Hardware Security: Advanced Topics and Trends Ad

As an Amazon Associate I earn from qualifying purchases.

More Hardware Security: Advanced Topics and Trends questions

  1. In a device that updates firmware using two areas, side A and side B, when is the most appropriate time to advance the minimum version number recorded in eFuses for anti-rollback to the new version number?
  2. Which correctly describes a hardware bill of materials (HBOM)?
  3. Which is an appropriate way to think about security when combining chiplets from several companies in one package?
  4. Which correctly pairs techniques that protect semiconductor designs with the untrusted party each mainly assumes?
  5. Assuming reverse engineering that reads the circuit by removing a chip's layers one at a time and imaging them with an electron microscope, or by imaging its interior with X-rays, which is an appropriate design approach?