TPM, Secure Boot, Attestation, TEEs and Device Identity — DedSec Project

Modern device trust uses hardware-backed keys, measured boot, secure boot, attestation, and trusted execution concepts. These mechanisms answer different questions and should not be collapsed into “the hardware is secure.”

Learning objectives

By the end of this module you should be able to:

• Explain Secure Boot and connect it to a concrete trust boundary or security invariant.
• Explain Measured boot and connect it to a concrete trust boundary or security invariant.
• Explain TPM keys and connect it to a concrete trust boundary or security invariant.
• Explain Attestation and connect it to a concrete trust boundary or security invariant.
• Explain TEEs and connect it to a concrete trust boundary or security invariant.
• Explain Device identity and connect it to a concrete trust boundary or security invariant.

Deep concepts

1. Secure Boot

Secure Boot verifies components against an allowed trust policy before execution. It constrains unauthorized boot code but does not attest that a running application is correctly configured.

2. Measured boot

Measured boot records cryptographic measurements of boot components into protected state such as TPM PCRs. Measurements provide evidence; a verifier still needs policy for what measurements are acceptable.

3. TPM keys

TPMs can generate/seal keys, protect private key operations, and bind release to platform state. Backup/recovery design must consider what happens when hardware is replaced or measurements legitimately change.

4. Attestation

Attestation is evidence about a platform/workload state signed or vouched for by a trust anchor. Freshness, nonce/challenge handling, verifier trust, endorsement, privacy, and policy evaluation matter as much as the signature.

5. TEEs

Trusted execution environments aim to isolate code/data from parts of the surrounding system. Their boundary, memory protections, I/O path, side channels, rollback protection, and update mechanism are platform-specific.

6. Device identity

Hardware-backed device credentials can improve enrollment and workload identity, but device identity is not automatically user identity or authorization to a resource.

7. Key release

A powerful pattern is releasing a secret only when attestation satisfies policy. This turns measurement verification into an authorization dependency that must handle updates, failures, and revocation safely.

8. Lifecycle

Manufacturing, enrollment, ownership transfer, firmware update, credential rotation, RMA, decommissioning, and key destruction all affect hardware-rooted trust.

Authorized exercises

Exercise 1 — Draw a boot trust chain for a modern laptop or phone using public vendor documentation and distinguish verification from measurement

Draw a boot trust chain for a modern laptop or phone using public vendor documentation and distinguish verification from measurement.

Exercise 2 — Design an attestation verifier state machine: challenge, evidence, freshness check, identity validation, policy evaluation, decision, logging

Design an attestation verifier state machine: challenge, evidence, freshness check, identity validation, policy evaluation, decision, logging.

Exercise 3 — Create a recovery plan for an application whose encryption key is sealed to hardware state and the motherboard must be replaced

Create a recovery plan for an application whose encryption key is sealed to hardware state and the motherboard must be replaced.

Knowledge checks

1. Explain the most important trust boundary in TPM, Secure Boot, Attestation, TEEs and Device Identity without naming a security tool.
2. Give one example where cryptographic or authentication success still does not imply authorization success.
3. Describe one stale-state or replay condition relevant to this module.
4. Identify one telemetry source that can support a strong conclusion and one blind spot it still leaves.
5. Explain how you would turn a discovered weakness into a regression test rather than a one-time finding.

Guided study workflow