Services Layer Deep Dive
Attestation Service
Provides cryptographic proof of platform identity and firmware integrity.
Capabilities:
- SPDM Responder — proves identity to external verifiers
- SPDM Requester — verifies downstream devices
- Local Verifier — on-platform trust decisions (for air-gapped environments)
- Evidence format: RATS EAT (Entity Attestation Token) with OCP profile
DICE Integration
The PRoT uses a DICE (Device Identifier Composition Engine) chain to build layered measurements from hardware through each firmware stage:
graph LR
HW["Hardware"] -->|CDI| BR["Boot ROM"]
BR -->|CDI| S1["Stage 1 FW"]
S1 -->|CDI| S2["Stage 2 FW"]
S2 -->|CDI| RT["Runtime"]
RT -->|CDI| FI["Final Identity"]
style HW fill:#a05050,color:#fff
style BR fill:#a09825,color:#fff
style S1 fill:#509060,color:#fff
style S2 fill:#4a70a0,color:#fff
style RT fill:#804080,color:#fff
style FI fill:#705090,color:#fff
Each stage measures the next and derives a new Compound Device Identifier (CDI), creating an unforgeable chain of trust.
Firmware Update & Recovery
Follows NIST SP 800-193 (Platform Firmware Resiliency):
- Dual-bank storage — Active bank + recovery bank
- Authenticated packages — Cryptographic signature verification
- Rollback protection — Anti-rollback counters prevent downgrade attacks
- Automatic recovery — Falls back to known-good bank on boot failure
Telemetry Service
Platform monitoring via PLDM Type 2:
- Temperature, voltage, and power sensors
- Platform Data Records (PDR) repository
- Standardized sensor descriptions for management tools