TPM & device attestation

Devices use a hardware security module — a TPM (Trusted Platform Module) — to establish a strong, hardware-rooted identity and to protect sensitive material. This page explains what the TPM is used for and how attestation works during provisioning.

What the TPM is used for

  • Device identity. The TPM holds keys that uniquely and verifiably identify the device. These keys cannot be copied off the device.
  • Attestation. During provisioning, the device proves its identity and reports its integrity to the platform before it receives credentials.
  • Disk unlock. When disk encryption is enabled, the TPM stores the keys that unlock the encrypted areas, bound to the device’s boot state.

Attestation during provisioning

When a device onboards using zero-touch provisioning or a provisioning policy, it presents hardware-backed identity to the platform and responds to a challenge that proves the keys really live in this device’s TPM. Only after this succeeds does the device receive its credentials. This is what makes it safe to ship unconfigured hardware directly to a site: an attacker cannot impersonate a device without its TPM.

For attestation to succeed, the platform must trust the device’s TPM. This is established through the manufacturer’s certificates, which an administrator registers in the platform so that devices from a given manufacturer or product line can be verified.

Attestation configuration and status

You can configure attestation expectations for a device, and the device reports its measured integrity values back to the platform, where you can review them on the device. Use this to confirm that devices booted in the expected state.

Requirements

  • The device must have a functioning TPM.
  • The device’s clock must be reasonably accurate for the secure exchange to succeed — see Time synchronization.