Hardware Security

In confidential computing on the cloud, what is the purpose of CPU features that encrypt virtual machine memory (such as AMD SEV or Intel TDX)?

  1. ATo always double virtual machine speed
  2. BTo increase virtual machine memory capacity
  3. CTo keep data inside a virtual machine unreadable even by the cloud provider's hypervisor and administrators
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Answer: C. To keep data inside a virtual machine unreadable even by the cloud provider's hypervisor and administrators

Normally a virtual machine's memory can be freely read and written by the hypervisor running it, so users must trust the cloud provider. With memory encryption, per-VM keys are managed only inside the CPU, and memory contents stay encrypted outside it, hiding them from the hypervisor and from attackers reading memory directly. It is used together with remote attestation.

  • A. Encryption may slow things slightly.
  • B. Capacity does not increase.
  • C. Correct. The aim is to avoid having to trust the infrastructure.
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More Hardware Security questions

  1. Which describes a PUF (physically unclonable function)?
  2. What is the advantage of using a PUF for key storage?
  3. What property does an SRAM PUF exploit?
  4. Why is error correction (such as helper data) combined with PUFs when deriving keys?
  5. Which describes a true random number generator (TRNG) built into a chip?