policyverify attestor

Emits a SLSA Verification Summary Attestation (VSA) recording the outcome of a cilock verify run against a signed policy.

What it captures

The attestor embeds slsa.VerificationSummary and serializes per the SLSA VSA v1 spec:

• verifier.id — hard-coded to "aflock". Identifies who produced the VSA.
• timeVerified — wall-clock timestamp captured when Attest finishes verification.
• policy.uri — set to the policy predicate type constant (policy.PolicyPredicate); the policy's content identity is in policy.digest.
• policy.digest — digest set computed from the policy DSSE envelope payload (the canonical policy bytes that were signature-verified).
• inputAttestations[] — for every policy step, each passing collection's Reference URI plus a computed digest. When verification fails, rejected collections are also included so downstream consumers can see what was considered.
• verificationResult — "PASSED" or "FAILED", derived from the policy engine's accepted return value.

Additional fields outside the SLSA predicate:

• denyReasons[] — per-collection rejection records (reference, collection_name, message).

Subjects emitted by the attestor (via the Subjecter interface):

• One artifact:<digest> entry per subject digest supplied to verify.
• One policy:<uri> entry pointing at the verified policy.

When to use

Run as part of cilock verify at a release or deploy gate. The resulting VSA is a portable, signed statement that "this policy passed against these subjects at this time." Downstream consumers (admission controllers, deploy pipelines, auditors) can trust the VSA without re-fetching the full evidence chain or re-running the policy engine.

Flags

None. The attestor is configured programmatically by cilock verify via setter methods (SetPolicyEnvelope, SetSubjectDigests, SetCollectionSource, SetPolicyVerificationOptions, SetAiServerURL, SetKMSProviderOptions) — there are no user-facing attestor flags.

Output shape

{
  "verifier": { "id": "aflock" },
  "timeVerified": "2026-05-21T12:34:56Z",
  "policy": {
    "uri": "https://witness.dev/attestations/policy/v0.1",
    "digest": { "sha256": "..." }
  },
  "inputAttestations": [
    { "uri": "...", "digest": { "sha256": "..." } }
  ],
  "verificationResult": "PASSED",
  "denyReasons": []
}

Gotchas

• Verify-type only. RunType is attestation.VerifyRunType, so this attestor cannot be selected inside cilock run. It is wired in automatically by cilock verify.
• Policy identity, not policy contents. The VSA records the policy envelope digest plus the predicate-type URI in policy.uri — it does not embed the policy body. Consumers must dereference the digest against their policy store.
• Verifier ID is fixed. The verifier.id is hard-coded to "aflock"; it does not reflect the signing identity or hostname of the verifier.
• Rejected attestations only listed on failure. When verificationResult == "PASSED", inputAttestations contains only the passing collections that satisfied each step.
• Policy signature is verified first. If the policy envelope signature fails to verify, Attest returns an error before any VSA is produced — no failed VSA is emitted for signature-level failures.

CLI example

See the constraint summary + reproduction recipe at https://github.com/aflock-ai/attestor-compliance-examples/tree/main/41-policyverify. This attestor is currently blocked or doc-only — the linked example explains why and shows the recipe to validate once the constraint is removed.

See also

• Catalog row
• Verify in a release gate
• SLSA VSA spec