# StellaOps Signer

Signer validates callers, enforces Proof-of-Entitlement, and produces signed DSSE bundles for SBOMs, reports, and exports.

## Latest updates (Sprint 11 · 2025-10-21)
- `/sign/dsse` pipeline landed with Authority OpTok + PoE enforcement, Fulcio/KMS signing modes, and deterministic DSSE bundles ready for Attestor logging.
- `/verify/referrers` endpoint exposes release-integrity checks against scanner OCI referrers so callers can confirm digests before requesting signatures.
- Plan quota enforcement (QPS/concurrency/artifact size) and audit/metrics wiring now align with the Sprint 11 signing-chain release.

## Responsibilities
- Enforce Proof-of-Entitlement and plan quotas before signing artifacts.
- Support keyless (Fulcio) and keyful (KMS/HSM) signing backends.
- Verify scanner release integrity via OCI referrers prior to issuing signatures.
- Emit DSSE payloads consumed by Attestor/Export Center and maintain comprehensive audit trails.

## Key components
- `StellaOps.Signer` service host.
- Crypto providers under `StellaOps.Cryptography.*`.

## Integrations & dependencies
- Authority for OpTok + PoE validation.
- Licensing Service for entitlement introspection.
- OCI registries (Referrers API) for scanner release verification.
- Attestor for transparency logging and Rekor ingestion.
- Export Center and CLI for artifact signing flows.

## API quick reference
- `POST /api/v1/signer/sign/dsse` — validate OpTok/PoE, enforce quotas, return DSSE bundle with signing identity metadata.
- `GET /api/v1/signer/verify/referrers` — report scanner release signer and trust verdict for a supplied image digest.

## Operational notes
- Key management via Authority/DevOps runbooks.
- Metrics for signing latency/throttle states.
- Offline kit integration for signature verification.

## Backlog references
- SIG docs/tasks in ../../TASKS.md (e.g., DOCS-SIG-26-006).

## Epic alignment
- **Epic 10 – Export Center:** provide signing pipelines, cosign interoperability, and provenance manifests for bundle promotion.
- **Epic 19 – Attestor Console:** supply DSSE payloads and Proof-of-Entitlement enforcement feeding attestation workflows described in `docs/modules/attestor/`.