- Introduced AuthorityAdvisoryAiOptions and related classes for managing advisory AI configurations, including remote inference options and tenant-specific settings. - Added AuthorityApiLifecycleOptions to control API lifecycle settings, including legacy OAuth endpoint configurations. - Implemented validation and normalization methods for both advisory AI and API lifecycle options to ensure proper configuration. - Created AuthorityNotificationsOptions and its related classes for managing notification settings, including ack tokens, webhooks, and escalation options. - Developed IssuerDirectoryClient and related models for interacting with the issuer directory service, including caching mechanisms and HTTP client configurations. - Added support for dependency injection through ServiceCollectionExtensions for the Issuer Directory Client. - Updated project file to include necessary package references for the new Issuer Directory Client library.
		
			
				
	
	
		
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			534 lines
		
	
	
		
			24 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
# component_architecture_attestor.md — **Stella Ops Attestor** (2025Q4)
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> Derived from Epic 19 – Attestor Console with provenance hooks aligned to the Export Center bundle workflows scoped in Epic 10.
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> **Scope.** Implementation‑ready architecture for the **Attestor**: the service that **submits** DSSE envelopes to **Rekor v2**, retrieves/validates inclusion proofs, caches results, and exposes verification APIs. It accepts DSSE **only** from the **Signer** over mTLS, enforces chain‑of‑trust to Stella Ops roots, and returns `{uuid, index, proof, logURL}` to calling services (Scanner.WebService for SBOMs; backend for final reports; Excititor exports when configured).
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---
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## 0) Mission & boundaries
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**Mission.** Turn a signed DSSE envelope from the Signer into a **transparency‑logged, verifiable fact** with a durable, replayable proof (Merkle inclusion + (optional) checkpoint anchoring). Provide **fast verification** for downstream consumers and a stable retrieval interface for UI/CLI.
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**Boundaries.**
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* Attestor **does not sign**; it **must not** accept unsigned or third‑party‑signed bundles.
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* Attestor **does not decide PASS/FAIL**; it logs attestations for SBOMs, reports, and export artifacts.
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* Rekor v2 backends may be **local** (self‑hosted) or **remote**; Attestor handles both with retries, backoff, and idempotency.
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---
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## 1) Topology & dependencies
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**Process shape:** single stateless service `stellaops/attestor` behind mTLS.
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**Dependencies:**
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* **Signer** (caller) — authenticated via **mTLS** and **Authority** OpToks.
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* **Rekor v2** — tile‑backed transparency log endpoint(s).
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* **MinIO (S3)** — optional archive store for DSSE envelopes & verification bundles.
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* **MongoDB** — local cache of `{uuid, index, proof, artifactSha256, bundleSha256}`; job state; audit.
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* **Redis** — dedupe/idempotency keys and short‑lived rate‑limit buckets.
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* **Licensing Service (optional)** — “endorse” call for cross‑log publishing when customer opts‑in.
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Trust boundary: **Only the Signer** is allowed to call submission endpoints; enforced by **mTLS peer cert allowlist** + `aud=attestor` OpTok.
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---
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### Roles, identities & scopes
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- **Subjects** — immutable digests for artifacts (container images, SBOMs, reports) referenced in DSSE envelopes.
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- **Issuers** — authenticated builders/scanners/policy engines signing evidence; tracked with mode (`keyless`, `kms`, `hsm`, `fido2`) and tenant scope.
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- **Consumers** — Scanner, Export Center, CLI, Console, Policy Engine that verify proofs using Attestor APIs.
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- **Authority scopes** — `attestor.write`, `attestor.verify`, `attestor.read`, and administrative scopes for key management; all calls mTLS/DPoP-bound.
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### Supported predicate types
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- `StellaOps.BuildProvenance@1`
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- `StellaOps.SBOMAttestation@1`
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- `StellaOps.ScanResults@1`
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- `StellaOps.PolicyEvaluation@1`
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- `StellaOps.VEXAttestation@1`
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- `StellaOps.RiskProfileEvidence@1`
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Each predicate embeds subject digests, issuer metadata, policy context, materials, and optional transparency hints. Unsupported predicates return `422 predicate_unsupported`.
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> **Golden fixtures:** Deterministic JSON statements for each predicate live in `src/Attestor/StellaOps.Attestor.Types/samples`. They are kept stable by the `StellaOps.Attestor.Types.Tests` project so downstream docs and contracts can rely on them without drifting.
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### Envelope & signature model
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- DSSE envelopes canonicalised (stable JSON ordering) prior to hashing.
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- Signature modes: keyless (Fulcio cert chain), keyful (KMS/HSM), hardware (FIDO2/WebAuthn). Multiple signatures allowed.
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- Rekor entry stores bundle hash, certificate chain, and optional witness endorsements.
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- Archive CAS retains original envelope plus metadata for offline verification.
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- Envelope serializer emits **compact** (canonical, minified) and **expanded** (annotated, indented) JSON variants off the same canonical byte stream so hashing stays deterministic while humans get context.
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- Payload handling supports **optional compression** (`gzip`, `brotli`) with compression metadata recorded in the expanded view and digesting always performed over the uncompressed bytes.
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- Expanded envelopes surface **detached payload references** (URI, digest, media type, size) so large artifacts can live in CAS/object storage while the canonical payload remains embedded for verification.
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- Payload previews auto-render JSON or UTF-8 text in the expanded output to simplify triage in air-gapped and offline review flows.
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### Verification pipeline overview
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1. Fetch envelope (from request, cache, or storage) and validate DSSE structure.
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2. Verify signature(s) against configured trust roots; evaluate issuer policy.
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3. Retrieve or acquire inclusion proof from Rekor (primary + optional mirror).
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4. Validate Merkle proof against checkpoint; optionally verify witness endorsement.
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5. Return cached verification bundle including policy verdict and timestamps.
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### UI & CLI touchpoints
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- Console: Evidence browser, verification report, chain-of-custody graph, issuer/key management, attestation workbench, bulk verification views.
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- CLI: `stella attest sign|verify|list|fetch|key` with offline verification and export bundle support.
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- SDKs expose sign/verify primitives for build pipelines.
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### Performance & observability targets
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- Throughput goal: ≥1 000 envelopes/minute per worker with cached verification.
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- Metrics: `attestor_submission_total`, `attestor_verify_seconds`, `attestor_rekor_latency_seconds`, `attestor_cache_hit_ratio`.
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- Logs include `tenant`, `issuer`, `subjectDigest`, `rekorUuid`, `proofStatus`; traces cover submission → Rekor → cache → response path.
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---
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## 2) Data model (Mongo)
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Database: `attestor`
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**Collections & schemas**
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* `entries`
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  ```
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  { _id: "<rekor-uuid>",
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    artifact: { sha256: "<sha256>", kind: "sbom|report|vex-export", imageDigest?, subjectUri? },
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    bundleSha256: "<sha256>",                           // canonicalized DSSE
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    index: <int>,                                       // log index/sequence if provided by backend
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    proof: {                                            // inclusion proof
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      checkpoint: { origin, size, rootHash, timestamp },
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      inclusion: { leafHash, path[] }                   // Merkle path (tiles)
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    },
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    log: { url, logId? },
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    createdAt, status: "included|pending|failed",
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    signerIdentity: { mode: "keyless|kms", issuer, san?, kid? }
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  }
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  ```
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* `dedupe`
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  ```
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  { key: "bundle:<sha256>", rekorUuid, createdAt, ttlAt }     // idempotency key
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  ```
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* `audit`
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  ```
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  { _id, ts, caller: { cn, mTLSThumbprint, sub, aud },        // from mTLS + OpTok
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    action: "submit|verify|fetch",
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    artifactSha256, bundleSha256, rekorUuid?, index?, result, latencyMs, backend }
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  ```
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Indexes:
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* `entries` on `artifact.sha256`, `bundleSha256`, `createdAt`, and `{status:1, createdAt:-1}`.
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* `dedupe.key` unique (TTL 24–48h).
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* `audit.ts` for time‑range queries.
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---
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## 3) Input contract (from Signer)
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**Attestor accepts only** DSSE envelopes that satisfy all of:
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1. **mTLS** peer certificate maps to `signer` service (CA‑pinned).
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2. **Authority** OpTok with `aud=attestor`, `scope=attestor.write`, DPoP or mTLS bound.
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3. DSSE envelope is **signed by the Signer’s key** (or includes a **Fulcio‑issued** cert chain) and **chains to configured roots** (Fulcio/KMS).
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4. **Predicate type** is one of Stella Ops types (sbom/report/vex‑export) with valid schema.
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5. `subject[*].digest.sha256` is present and canonicalized.
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**Wire shape (JSON):**
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```json
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{
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  "bundle": { "dsse": { "payloadType": "application/vnd.in-toto+json", "payload": "<b64>", "signatures": [ ... ] },
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              "certificateChain": [ "-----BEGIN CERTIFICATE-----..." ],
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              "mode": "keyless" },
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  "meta": {
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    "artifact": { "sha256": "<subject sha256>", "kind": "sbom|report|vex-export", "imageDigest": "sha256:..." },
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    "bundleSha256": "<sha256 of canonical dsse>",
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    "logPreference": "primary",               // "primary" | "mirror" | "both"
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    "archive": true                           // whether Attestor should archive bundle to S3
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  }
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}
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```
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---
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## 4) APIs
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### 4.1 Signing
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`POST /api/v1/attestations:sign` *(mTLS + OpTok required)*
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* **Purpose**: Deterministically wrap Stella Ops payloads in DSSE envelopes before Rekor submission. Reuses the submission rate limiter and honours caller tenancy/audience scopes.
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* **Body**:
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  ```json
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  {
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    "keyId": "signing-key-id",
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    "payloadType": "application/vnd.in-toto+json",
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    "payload": "<base64 payload>",
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    "mode": "keyless|keyful|kms",
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    "certificateChain": ["-----BEGIN CERTIFICATE-----..."],
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    "artifact": {
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      "sha256": "<subject sha256>",
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      "kind": "sbom|report|vex-export",
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      "imageDigest": "sha256:...",
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      "subjectUri": "oci://..."
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    },
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    "logPreference": "primary|mirror|both",
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    "archive": true
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  }
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  ```
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* **Behaviour**:
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  * Resolve the signing key from `attestor.signing.keys[]` (includes algorithm, provider, and optional KMS version).
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  * Compute DSSE pre‑authentication encoding, sign with the resolved provider (default EC, BouncyCastle Ed25519, or File‑KMS ES256), and add static + request certificate chains.
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  * Canonicalise the resulting bundle, derive `bundleSha256`, and mirror the request meta shape used by `/api/v1/rekor/entries`.
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  * Emit `attestor.sign_total{result,algorithm,provider}` and `attestor.sign_latency_seconds{algorithm,provider}` metrics and append an audit row (`action=sign`).
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* **Response 200**:
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  ```json
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  {
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    "bundle": { "dsse": { "payloadType": "...", "payload": "...", "signatures": [{ "keyid": "signing-key-id", "sig": "..." }] }, "certificateChain": ["..."], "mode": "kms" },
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    "meta": { "artifact": { "sha256": "...", "kind": "sbom" }, "bundleSha256": "...", "logPreference": "primary", "archive": true },
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    "key": { "keyId": "signing-key-id", "algorithm": "ES256", "mode": "kms", "provider": "kms", "signedAt": "2025-11-01T12:34:56Z" }
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  }
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  ```
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* **Errors**: `400 key_not_found`, `400 payload_missing|payload_invalid_base64|artifact_sha_missing`, `400 mode_not_allowed`, `403 client_certificate_required`, `401 invalid_token`, `500 signing_failed`.
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### 4.2 Submission
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`POST /api/v1/rekor/entries`  *(mTLS + OpTok required)*
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* **Body**: as above.
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* **Behavior**:
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  * Verify caller (mTLS + OpTok).
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  * Validate DSSE bundle (signature, cert chain to Fulcio/KMS; DSSE structure; payloadType allowed).
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  * Idempotency: compute `bundleSha256`; check `dedupe`. If present, return existing `rekorUuid`.
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  * Submit canonicalized bundle to Rekor v2 (primary or mirror according to `logPreference`).
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  * Retrieve **inclusion proof** (blocking until inclusion or up to `proofTimeoutMs`); if backend returns promise only, return `status=pending` and retry asynchronously.
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  * Persist `entries` record; archive DSSE to S3 if `archive=true`.
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* **Response 200**:
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  ```json
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  {
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    "uuid": "…",
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    "index": 123456,
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    "proof": {
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      "checkpoint": { "origin": "rekor@site", "size": 987654, "rootHash": "…", "timestamp": "…" },
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      "inclusion": { "leafHash": "…", "path": ["…","…"] }
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    },
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    "logURL": "https://rekor…/api/v2/log/…/entries/…",
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    "status": "included"
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  }
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  ```
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* **Errors**: `401 invalid_token`, `403 not_signer|chain_untrusted`, `409 duplicate_bundle` (with existing `uuid`), `502 rekor_unavailable`, `504 proof_timeout`.
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### 4.3 Proof retrieval
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`GET /api/v1/rekor/entries/{uuid}`
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* Returns `entries` row (refreshes proof from Rekor if stale/missing).
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* Accepts `?refresh=true` to force backend query.
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### 4.4 Verification (third‑party or internal)
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`POST /api/v1/rekor/verify`
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* **Body** (one of):
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  * `{ "uuid": "…" }`
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  * `{ "bundle": { …DSSE… } }`
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  * `{ "artifactSha256": "…" }`  *(looks up most recent entry)*
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* **Checks**:
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  1. **Bundle signature** → cert chain to Fulcio/KMS roots configured.
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  2. **Inclusion proof** → recompute leaf hash; verify Merkle path against checkpoint root.
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  3. Optionally verify **checkpoint** against local trust anchors (if Rekor signs checkpoints).
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  4. Confirm **subject.digest** matches caller‑provided hash (when given).
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  5. Fetch **transparency witness** statement when enabled; cache results and downgrade status to WARN when endorsements are missing or mismatched.
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* **Response**:
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  ```json
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  { "ok": true, "uuid": "…", "index": 123, "logURL": "…", "checkedAt": "…" }
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  ```
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### 4.5 Bulk verification
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`POST /api/v1/rekor/verify:bulk` enqueues a verification job containing up to `quotas.bulk.maxItemsPerJob` items. Each item mirrors the single verification payload (uuid | artifactSha256 | subject+envelopeId, optional policyVersion/refreshProof). The handler persists a MongoDB job document (`bulk_jobs` collection) and returns `202 Accepted` with a job descriptor and polling URL.
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`GET /api/v1/rekor/verify:bulk/{jobId}` returns progress and per-item results (subject/uuid, status, issues, cached verification report if available). Jobs are tenant- and subject-scoped; only the initiating principal can read their progress.
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**Worker path:** `BulkVerificationWorker` claims queued jobs (`status=queued → running`), executes items sequentially through the cached verification service, updates progress counters, and records metrics:
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- `attestor.bulk_jobs_total{status}` – completed/failed jobs
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- `attestor.bulk_job_duration_seconds{status}` – job runtime
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- `attestor.bulk_items_total{status}` – per-item outcomes (`succeeded`, `verification_failed`, `exception`)
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The worker honours `bulkVerification.itemDelayMilliseconds` for throttling and reschedules persistence conflicts with optimistic version checks. Results hydrate the verification cache; failed items record the error reason without aborting the overall job.
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---
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## 5) Rekor v2 driver (backend)
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* **Canonicalization**: DSSE envelopes are **normalized** (stable JSON ordering, no insignificant whitespace) before hashing and submission.
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* **Transport**: HTTP/2 with retries (exponential backoff, jitter), budgeted timeouts.
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* **Idempotency**: if backend returns “already exists,” map to existing `uuid`.
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* **Proof acquisition**:
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  * In synchronous mode, poll the log for inclusion up to `proofTimeoutMs`.
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  * In asynchronous mode, return `pending` and schedule a **proof fetcher** job (Mongo job doc + backoff).
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* **Mirrors/dual logs**:
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  * When `logPreference="both"`, submit to primary and mirror; store **both** UUIDs (primary canonical).
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  * Optional **cloud endorsement**: POST to the Stella Ops cloud `/attest/endorse` with `{uuid, artifactSha256}`; store returned endorsement id.
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---
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## 6) Security model
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* **mTLS required** for submission from **Signer** (CA‑pinned).
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* **Authority token** with `aud=attestor` and DPoP/mTLS binding must be presented; Attestor verifies both.
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* **Bundle acceptance policy**:
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  * DSSE signature must chain to the configured **Fulcio** (keyless) or **KMS/HSM** roots.
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  * SAN (Subject Alternative Name) must match **Signer identity** policy (e.g., `urn:stellaops:signer` or pinned OIDC issuer).
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  * Predicate `predicateType` must be on allowlist (sbom/report/vex-export).
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  * `subject.digest.sha256` values must be present and well‑formed (hex).
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* **No public submission** path. **Never** accept bundles from untrusted clients.
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* **Client certificate allowlists**: optional `security.mtls.allowedSubjects` / `allowedThumbprints` tighten peer identity checks beyond CA pinning.
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* **Rate limits**: token-bucket per caller derived from `quotas.perCaller` (QPS/burst) returns `429` + `Retry-After` when exceeded.
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* **Scope enforcement**: API separates `attestor.write`, `attestor.verify`, and `attestor.read` policies; verification/list endpoints accept read or verify scopes while submission endpoints remain write-only.
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* **Request hygiene**: JSON content-type is mandatory (415 returned otherwise); DSSE payloads are capped (default 2 MiB), certificate chains limited to six entries, and signatures to six per envelope to mitigate parsing abuse.
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* **Redaction**: Attestor never logs secret material; DSSE payloads **should** be public by design (SBOMs/reports). If customers require redaction, enforce policy at Signer (predicate minimization) **before** Attestor.
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---
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## 7) Storage & archival
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* **Entries** in Mongo provide a local ledger keyed by `rekorUuid` and **artifact sha256** for quick reverse lookups.
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* **S3 archival** (if enabled):
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  ```
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  s3://stellaops/attest/
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    dsse/<bundleSha256>.json
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    proof/<rekorUuid>.json
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    bundle/<artifactSha256>.zip               # optional verification bundle
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  ```
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* **Verification bundles** (zip):
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  * DSSE (`*.dsse.json`), proof (`*.proof.json`), `chain.pem` (certs), `README.txt` with verification steps & hashes.
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---
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## 8) Observability & audit
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**Metrics** (Prometheus):
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* `attestor.sign_total{result,algorithm,provider}`
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* `attestor.sign_latency_seconds{algorithm,provider}`
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* `attestor.submit_total{result,backend}`
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* `attestor.submit_latency_seconds{backend}`
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* `attestor.proof_fetch_total{subject,issuer,policy,result,attestor.log.backend}`
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* `attestor.verify_total{subject,issuer,policy,result}`
 | 
						||
* `attestor.verify_latency_seconds{subject,issuer,policy,result}`
 | 
						||
* `attestor.dedupe_hits_total`
 | 
						||
* `attestor.errors_total{type}`
 | 
						||
 | 
						||
SLO guardrails:
 | 
						||
 | 
						||
* `attestor.verify_latency_seconds` P95 ≤ 2 s per policy.
 | 
						||
* `attestor.verify_total{result="failed"}` ≤ 1 % of `attestor.verify_total` over 30 min rolling windows.
 | 
						||
 | 
						||
**Correlation**:
 | 
						||
 | 
						||
* HTTP callers may supply `X-Correlation-Id`; Attestor will echo the header and push `CorrelationId` into the log scope for cross-service tracing.
 | 
						||
 | 
						||
**Tracing**:
 | 
						||
 | 
						||
* Spans: `attestor.sign`, `validate`, `rekor.submit`, `rekor.poll`, `persist`, `archive`, `attestor.verify`, `attestor.verify.refresh_proof`.
 | 
						||
 | 
						||
**Audit**:
 | 
						||
 | 
						||
* Immutable `audit` rows (ts, caller, action, hashes, uuid, index, backend, result, latency).
 | 
						||
 | 
						||
---
 | 
						||
 | 
						||
## 9) Configuration (YAML)
 | 
						||
 | 
						||
```yaml
 | 
						||
attestor:
 | 
						||
  listen: "https://0.0.0.0:8444"
 | 
						||
  security:
 | 
						||
    mtls:
 | 
						||
      caBundle: /etc/ssl/signer-ca.pem
 | 
						||
      requireClientCert: true
 | 
						||
    authority:
 | 
						||
      issuer: "https://authority.internal"
 | 
						||
      jwksUrl: "https://authority.internal/jwks"
 | 
						||
      requireSenderConstraint: "dpop"   # or "mtls"
 | 
						||
    signerIdentity:
 | 
						||
      mode: ["keyless","kms"]
 | 
						||
      fulcioRoots: ["/etc/fulcio/root.pem"]
 | 
						||
      allowedSANs: ["urn:stellaops:signer"]
 | 
						||
      kmsKeys: ["kms://cluster-kms/stellaops-signer"]
 | 
						||
    submissionLimits:
 | 
						||
      maxPayloadBytes: 2097152
 | 
						||
      maxCertificateChainEntries: 6
 | 
						||
      maxSignatures: 6
 | 
						||
  signing:
 | 
						||
    preferredProviders: ["kms","bouncycastle.ed25519","default"]
 | 
						||
    kms:
 | 
						||
      enabled: true
 | 
						||
      rootPath: "/var/lib/stellaops/kms"
 | 
						||
      password: "${ATTESTOR_KMS_PASSWORD}"
 | 
						||
    keys:
 | 
						||
      - keyId: "kms-primary"
 | 
						||
        algorithm: ES256
 | 
						||
        mode: kms
 | 
						||
        provider: "kms"
 | 
						||
        providerKeyId: "kms-primary"
 | 
						||
        kmsVersionId: "v1"
 | 
						||
      - keyId: "ed25519-offline"
 | 
						||
        algorithm: Ed25519
 | 
						||
        mode: keyful
 | 
						||
        provider: "bouncycastle.ed25519"
 | 
						||
        materialFormat: base64
 | 
						||
        materialPath: "/etc/stellaops/keys/ed25519.key"
 | 
						||
        certificateChain:
 | 
						||
          - "-----BEGIN CERTIFICATE-----...-----END CERTIFICATE-----"
 | 
						||
  rekor:
 | 
						||
    primary:
 | 
						||
      url: "https://rekor-v2.internal"
 | 
						||
      proofTimeoutMs: 15000
 | 
						||
      pollIntervalMs: 250
 | 
						||
      maxAttempts: 60
 | 
						||
    mirror:
 | 
						||
      enabled: false
 | 
						||
      url: "https://rekor-v2.mirror"
 | 
						||
  mongo:
 | 
						||
    uri: "mongodb://mongo/attestor"
 | 
						||
  s3:
 | 
						||
    enabled: true
 | 
						||
    endpoint: "http://minio:9000"
 | 
						||
    bucket: "stellaops"
 | 
						||
    prefix: "attest/"
 | 
						||
    objectLock: "governance"
 | 
						||
  redis:
 | 
						||
    url: "redis://redis:6379/2"
 | 
						||
  quotas:
 | 
						||
    perCaller:
 | 
						||
      qps: 50
 | 
						||
      burst: 100
 | 
						||
```
 | 
						||
 | 
						||
**Notes:**
 | 
						||
 | 
						||
* `signing.preferredProviders` defines the resolution order when multiple providers support the requested algorithm. Omit to fall back to registration order.
 | 
						||
* File-backed KMS (`signing.kms`) is required when at least one key uses `mode: kms`; the password should be injected via secret store or environment.
 | 
						||
* For keyful providers, supply inline `material` or `materialPath` plus `materialFormat` (`pem` (default), `base64`, or `hex`). KMS keys ignore these fields and require `kmsVersionId`.
 | 
						||
* `certificateChain` entries are appended to returned bundles so offline verifiers do not need to dereference external stores.
 | 
						||
 | 
						||
---
 | 
						||
 | 
						||
## 10) End‑to‑end sequences
 | 
						||
 | 
						||
**A) Submit & include (happy path)**
 | 
						||
 | 
						||
```mermaid
 | 
						||
sequenceDiagram
 | 
						||
  autonumber
 | 
						||
  participant SW as Scanner.WebService
 | 
						||
  participant SG as Signer
 | 
						||
  participant AT as Attestor
 | 
						||
  participant RK as Rekor v2
 | 
						||
 | 
						||
  SW->>SG: POST /sign/dsse (OpTok+PoE)
 | 
						||
  SG-->>SW: DSSE bundle (+certs)
 | 
						||
  SW->>AT: POST /rekor/entries (mTLS + OpTok)
 | 
						||
  AT->>AT: Validate DSSE (chain to Fulcio/KMS; signer identity)
 | 
						||
  AT->>RK: submit(bundle)
 | 
						||
  RK-->>AT: {uuid, index?}
 | 
						||
  AT->>RK: poll inclusion until proof or timeout
 | 
						||
  RK-->>AT: inclusion proof (checkpoint + path)
 | 
						||
  AT-->>SW: {uuid, index, proof, logURL}
 | 
						||
```
 | 
						||
 | 
						||
**B) Verify by artifact digest (CLI)**
 | 
						||
 | 
						||
```mermaid
 | 
						||
sequenceDiagram
 | 
						||
  autonumber
 | 
						||
  participant CLI as stellaops verify
 | 
						||
  participant SW as Scanner.WebService
 | 
						||
  participant AT as Attestor
 | 
						||
 | 
						||
  CLI->>SW: GET /catalog/artifacts/{id}
 | 
						||
  SW-->>CLI: {artifactSha256, rekor: {uuid}}
 | 
						||
  CLI->>AT: POST /rekor/verify { uuid }
 | 
						||
  AT-->>CLI: { ok: true, index, logURL }
 | 
						||
```
 | 
						||
 | 
						||
---
 | 
						||
 | 
						||
## 11) Failure modes & responses
 | 
						||
 | 
						||
| Condition                             | Return                  | Details                                                   |          |              |
 | 
						||
| ------------------------------------- | ----------------------- | --------------------------------------------------------- | -------- | ------------ |
 | 
						||
| mTLS/OpTok invalid                    | `401 invalid_token`     | Include `WWW-Authenticate` DPoP challenge when applicable |          |              |
 | 
						||
| Bundle not signed by trusted identity | `403 chain_untrusted`   | DSSE accepted only from Signer identities                 |          |              |
 | 
						||
| Duplicate bundle                      | `409 duplicate_bundle`  | Return existing `uuid` (idempotent)                       |          |              |
 | 
						||
| Rekor unreachable/timeout             | `502 rekor_unavailable` | Retry with backoff; surface `Retry-After`                 |          |              |
 | 
						||
| Inclusion proof timeout               | `202 accepted`          | `status=pending`, background job continues to fetch proof |          |              |
 | 
						||
| Archive failure                       | `207 multi-status`      | Entry recorded; archive will retry asynchronously         |          |              |
 | 
						||
| Verification mismatch                 | `400 verify_failed`     | Include reason: chain                                     | leafHash | rootMismatch |
 | 
						||
 | 
						||
---
 | 
						||
 | 
						||
## 12) Performance & scale
 | 
						||
 | 
						||
* Stateless; scale horizontally.
 | 
						||
* **Targets**:
 | 
						||
 | 
						||
  * Submit+proof P95 ≤ **300 ms** (warm log; local Rekor).
 | 
						||
  * Verify P95 ≤ **30 ms** from cache; ≤ **120 ms** with live proof fetch.
 | 
						||
  * 1k submissions/minute per replica sustained.
 | 
						||
* **Hot caches**: `dedupe` (bundle hash → uuid), recent `entries` by artifact sha256.
 | 
						||
 | 
						||
---
 | 
						||
 | 
						||
## 13) Testing matrix
 | 
						||
 | 
						||
* **Happy path**: valid DSSE, inclusion within timeout.
 | 
						||
* **Idempotency**: resubmit same `bundleSha256` → same `uuid`.
 | 
						||
* **Security**: reject non‑Signer mTLS, wrong `aud`, DPoP replay, untrusted cert chain, forbidden predicateType.
 | 
						||
* **Rekor variants**: promise‑then‑proof, proof delayed, mirror dual‑submit, mirror failure.
 | 
						||
* **Verification**: corrupt leaf path, wrong root, tampered bundle.
 | 
						||
* **Throughput**: soak test with 10k submissions; latency SLOs, zero drops.
 | 
						||
 | 
						||
---
 | 
						||
 | 
						||
## 14) Implementation notes
 | 
						||
 | 
						||
* Language: **.NET 10** minimal API; `HttpClient` with **sockets handler** tuned for HTTP/2.
 | 
						||
* JSON: **canonical writer** for DSSE payload hashing.
 | 
						||
* Crypto: use **BouncyCastle**/**System.Security.Cryptography**; PEM parsing for cert chains.
 | 
						||
* Rekor client: pluggable driver; treat backend errors as retryable/non‑retryable with granular mapping.
 | 
						||
* Safety: size caps on bundles; decompress bombs guarded; strict UTF‑8.
 | 
						||
* CLI integration: `stellaops verify attestation <uuid|bundle|artifact>` calls `/rekor/verify`.
 | 
						||
 | 
						||
---
 | 
						||
 | 
						||
## 15) Optional features
 | 
						||
 | 
						||
* **Dual‑log** write (primary + mirror) and **cross‑log proof** packaging.
 | 
						||
* **Cloud endorsement**: send `{uuid, artifactSha256}` to Stella Ops cloud; store returned endorsement id for marketing/chain‑of‑custody.
 | 
						||
* **Checkpoint pinning**: periodically pin latest Rekor checkpoints to an external audit store for independent monitoring.
 | 
						||
 |