A security engineer is deciding between a trusted platform module (TPM) and a hardware security module (HSM) for a specific need on new hypervisor hosts. The requirement is to bind disk encryption keys to a known-good boot state so the volume unlocks only when firmware and boot components are unchanged. Which component fits this requirement, and why?
AThe TPM, because it stores platform configuration measurements and can seal keys so they release only when the measured boot state matches expected values.check_circle Correct
BThe HSM, because it is validated to a higher assurance level and therefore supersedes the TPM for any host-based key binding requirement.
CThe HSM, because it can attest to firmware integrity across the fleet and release keys centrally once each host reports a clean boot.
DThe TPM, because it performs high-volume network cryptographic operations for many tenants while keeping keys inside a shared boundary.
Distinguish that a TPM seals keys to a measured boot state on a host, whereas an HSM is a shared boundary for high-volume key operations. A TPM records boot component measurements in platform configuration registers and can seal a key so it is released only when those measurements match a known-good state, which directly meets a boot-bound disk encryption requirement that an HSM does not address.
Why A is correct: Sealing a key to platform configuration register values so it releases only under a known-good boot state is exactly what a TPM provides on a host.
Why B is wrong: Higher validation assurance does not give an HSM measured-boot sealing; that capability is specific to the TPM, so assurance level is the wrong basis for the choice.
Why C is wrong: Firmware measurement and boot-state sealing are TPM functions performed on the host itself; an HSM does not measure a server's boot sequence.
Why D is wrong: High-volume shared network crypto for tenants describes an HSM; a TPM is a low-throughput per-host root of trust, so the reasoning is inverted.
Answers that look right on this material and are not. Each one is a distractor from a different question in the CCSP bank for this domain.
Encrypt the master keys with a passphrase and store the encrypted blob in an object storage bucket protected by strict bucket policies and access logging.
errorWhy it is wrong: Wrapping the key and storing it in object storage is a reasonable pattern for lower assurance, but the plaintext key is still exposed in memory when unwrapped, so it fails the requirement that key material never exist in plaintext outside hardware.
A hardware security module attached to the host to store the workload encryption keys used by the guest virtual machines.
errorWhy it is wrong: An HSM protects key material and performs cryptographic operations, but it does not measure the host boot chain, so it cannot establish or attest the integrity of firmware and the bootloader.
It carries the encrypted customer workload traffic between tenants, so compromise would expose data in transit across the shared backbone.
errorWhy it is wrong: This describes the data plane, which handles workload traffic. Encrypting tenant traffic is important, but the data plane is not the aggregated control surface that the question asks about.