AIR V1 // SPEC // CYNTRISEC

Format	COSE_Sign1 (RFC 9052) + CWT (RFC 8392) + EAT (RFC 9711)
Signing	Ed25519 only · COSE alg `-8` · verify_strict semantics
Claims	17 total · 5 standard CWT/EAT + 12 private (keys `-65537` to `-65549`)
Platforms	AWS Nitro Enclaves · Intel TDX · NVIDIA H100 CC
Status	v1.0 frozen · closed profile, no extension mechanism

Internet-Draft

draft-tsyrulnikov-rats-attested-inference-receipt — IETF RATS working group area.

IPR disclosure: IPR 7182

What AIR does

An AIR receipt binds model identity (cryptographic hash), input/output hashes, attestation-linked measurements, and operational telemetry into a single signed artifact. One inference, one receipt, independently verifiable by any third party with standard COSE/CWT tooling.

AIR is attestation-linked but does not replace platform-specific attestation. It carries measurements and a hash reference to the platform attestation document. Verification splits into two concerns: AIR-local verification of the receipt itself, and platform-specific verification of the underlying attestation evidence.

Claim summary

Standard CWT/EAT:
  iss (1)             Issuer
  iat (6)             Issued-at (Unix seconds, uint only)
  cti (7)             Receipt ID (UUID v4, 16 bytes)
  eat_profile (265)   "https://cyntrisec.com/spec/air/v1"
  eat_nonce (10)      Optional client nonce (8-64 bytes)

AIR Private Claims:
  model_id (-65537)              Human-readable model name
  model_version (-65538)         Model version string
  model_hash (-65539)            SHA-256 of model weights
  request_hash (-65540)          SHA-256 of inference input
  response_hash (-65541)         SHA-256 of inference output
  attestation_doc_hash (-65542)  SHA-256 of platform attestation doc
  enclave_measurements (-65543)  Platform measurement registers
  policy_version (-65544)        Workload policy version
  sequence_number (-65545)       Monotonic counter per session
  execution_time_ms (-65546)     Inference wall-clock time
  memory_peak_mb (-65547)        Peak memory usage
  security_mode (-65548)         Workload security mode
  model_hash_scheme (-65549)     Optional: hash computation method

Schema (CDDL)

The full CDDL schema is in the Internet-Draft (Section 4.5 and Appendix A). Machine-readable: air-v1.cddl

Golden vectors

10 test vectors (2 valid, 8 invalid) covering all four verification layers. Available at air-v1/vectors/

v1-nitro-no-nonce — valid, Nitro measurements, no nonce
v1-tdx-with-nonce — valid, TDX measurements, with nonce
8 invalid vectors: wrong-key, wrong-alg, zero-model-hash, bad-measurement-length, nonce-mismatch, model-hash-mismatch, platform-mismatch, stale-iat

Implementations

Rust reference (Cyntrisec / EphemeralML) — full emitter + 4-layer verifier, 500+ tests, E2E on AWS Nitro + GCP TDX + GCP H100 CC
Python interop verifier — pycose + cbor2, validates all 10 golden vectors

RATS architecture mapping

Attester — confidential workload (TEE)
Verifier — AIR receipt verifier (AIR-local) + platform attestation verifier
Relying Party — auditor, compliance officer, end user
Endorser — TEE platform vendor or attestation service

Related work

draft-messous-eat-ai — EAT profile for AI agent identity (complementary; AIR covers per-inference execution)
SCITT — transparency service receipts (complementary; AIR receipts could be registered as SCITT statements)
RFC 9334 — RATS Architecture
RFC 9711 — Entity Attestation Token (EAT)

ATTESTEDINFERENCERECEIPT V1FROZEN