upstream.verified.claims and in the
attested session. A claim never just says “trusted”: each one
states its own assurance level. This page is the reference for reading them.
Each claim is an object with a status, a source, and a plain reason:
Claim status
status | Meaning |
|---|---|
asserted | The verifier’s evidence backs this claim. |
refuted | The evidence contradicts the claim (for example a stale platform TCB). Recorded, not hidden. |
unknown | The claim was not established. This is transparency, never a silent pass. |
Claim source
Thesource states who vouches for an asserted or refuted claim, so a hardware fact and an assertion
never look alike.
source | Assurance |
|---|---|
hardware_proven | From the verified TEE quote or its collateral. Strongest. |
verifier_derived | Computed by the verifier from verified evidence. |
provider_asserted | Published by the provider, not independently proven. |
operator_asserted | Declared by the gateway operator. Weakest. |
The claim vocabulary
| Claim | Asks |
|---|---|
tee_attested | Is this a genuine CPU TEE with an identity bound to the channel? |
tcb_up_to_date | Is the platform’s Trusted Computing Base current? |
os_known_good | Does the OS or platform image map to reviewed source? |
serving_software_known_good | Does the serving software map to reviewed source? |
gpu_attested | Is a genuine confidential-computing GPU attested and nonce-bound? |
model_weights_provenance | Are the served weights and quantization what they claim to be? |
TCB freshness
tcb_up_to_date is an honest tri-state read from the verifier’s reported TCB status:
- An up-to-date platform asserts the claim.
- A stale platform refutes it. The quote proves a stale TCB, so the gateway records the refuted claim rather than silently treating the platform as current.
- An absent status is
unknown.
How to read GPU attestation
gpu_attested becomes asserted (with source verifier_derived) when a provider’s NVIDIA
confidential-computing GPU attestation is verified and bound to the verification nonce. It proves a
genuine confidential GPU exists for that nonce. It does not prove that GPU is bound to the serving
CPU TEE for your specific request. That is why its source is verifier_derived rather than
hardware_proven, and why it never gates a session. Absent or unverified GPU evidence leaves the claim
unknown.
Using claims in a decision
- Require
tee_attestedto beassertedwith sourcehardware_proven. - Treat
serving_software_known_good: assertedas a stronger statement than aprovider_assertedclaim about software. - Decide your own policy on
tcb_up_to_date: refuted(serve with a recorded stale TCB, or reject). - Read
gpu_attestedas supplemental, not as a gate. - Treat any
unknownas “not proven”, and weigh it accordingly.