Verification Protocol¶

TRACE Trust Records are independently verifiable offline — no call to the issuer, no API, no trust-me-the-log-is-real.

Five-step verification¶

This is the normative protocol from §3.3 of the spec.

Step 1 — Parse the envelope¶

A TRACE Trust Record is a signed JSON object. The signature field contains a base64url-encoded Ed25519 (or ES256/ES384) signature over the canonical JSON of the record with signature and cnf removed.

import json, base64
from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PublicKey

record = json.load(open("session.trace.json"))
sig_bytes = base64.urlsafe_b64decode(record["signature"] + "==")
payload = {k: v for k, v in record.items() if k not in ("signature", "cnf")}
payload_bytes = json.dumps(payload, sort_keys=True, separators=(",", ":")).encode()

Step 2 — Resolve the public key¶

The cnf.jwk field embeds the public key. For TEE-issued records, this key is TEE-bound — its private half never leaves the measured enclave.

from cryptography.hazmat.primitives.serialization import load_der_public_key

jwk = record["cnf"]["jwk"]
# For ES256/ES384: reconstruct EC key from x/y
# For Ed25519: decode x directly
pub_key = Ed25519PublicKey.from_public_bytes(
    base64.urlsafe_b64decode(jwk["x"] + "==")
)

Step 3 — Verify the signature¶

pub_key.verify(sig_bytes, payload_bytes)
# Raises InvalidSignature if tampered — silent if valid
print("✓ Signature valid")

Step 4 — Check the EAT profile¶

assert record["eat_profile"] == "tag:agentrust.io,2026:trace-v0.1", "Unknown profile"
print("✓ eat_profile correct")

Step 5 — Appraise the claims¶

Interpret appraisal.status against your policy:

Status	Meaning
`affirming`	All evidence passed verifier appraisal
`warning`	Evidence passed but with conditions
`contraindicated`	Evidence failed — treat as untrusted
`none`	No appraisal performed (software-only Level 0)

status = record["appraisal"]["status"]
assert status == "affirming", f"Appraisal failed: {status}"
print(f"✓ Appraisal: {status}")

Verifying hardware-rooted records¶

For Level 2 records (TEE-issued), additionally verify that the cnf.jwk key is bound to the hardware measurement in runtime:

Fetch the Reference Integrity Manifest at runtime.rim_uri
Compare runtime.measurement against the RIM
Verify that cnf.jwk was endorsed by the TEE at that measurement

This chain proves the key that signed the TRACE record was generated inside the attested enclave — not by an operator process.

CLI verification¶

# Install
pip install agentrust-trace

# Verify a record
agentrust-trace verify session.trace.json --pubkey issuer.pub

# Verify with hardware check (fetches RIM from AMD/Intel/NVIDIA)
agentrust-trace verify session.trace.json --pubkey issuer.pub --check-hardware

# Batch verify
agentrust-trace verify *.trace.json --pubkey issuer.pub --summary

SCITT-anchored records¶

If transparency is set, the record is anchored in an append-only transparency log. Verify the anchor:

agentrust-trace verify-scitt session.trace.json \
  --transparency-log https://registry.agentrust.io

A valid SCITT receipt proves the record was included in the log and cannot be retroactively removed or modified.

What verification proves¶

Claim verified	What it means
Signature valid	The record was not tampered with after issuance
`cnf.jwk` hardware-bound	The signing key was generated inside a measured TEE
`policy.bundle_hash`	This exact Cedar policy was in force — not an approximate
`tool_transcript.hash`	The audit log is intact and matches the record
SCITT receipt valid	The record is in an append-only log — cannot be quietly deleted

What verification does NOT prove¶

Verification proves what happened during the recorded session under the stated policy, in the stated environment. It does not:

Prove the agent's internal reasoning was sound
Prove the policy was correctly authored for the intent
Prove tool call contents (only the hash of the transcript is in v0.1)
Replace ongoing monitoring

See Limitations for the full list.