# Mirror bundle signing runbook (CI)

## Prerequisites
- Ed25519 private key (PEM). Keep in CI secrets only.
- Base64-encode the PEM: `base64 -w0 mirror-ci-ed25519.pem > mirror-ci-ed25519.pem.b64`.
- Create CI secret `MIRROR_SIGN_KEY_B64` with that value.

## Pipeline step (Gitea example)
```
- name: Build/sign mirror thin bundle
  env:
    MIRROR_SIGN_KEY_B64: ${{ secrets.MIRROR_SIGN_KEY_B64 }}
    REQUIRE_PROD_SIGNING: 1
    OCI: 1
  run: |
    scripts/mirror/check_signing_prereqs.sh
    scripts/mirror/ci-sign.sh
```
Outputs are placed under `out/mirror/thin/` and `out/mirror/thin/oci/`; archive these as artifacts.

### How to add the secret in Gitea (one-time)
1. Repository → Settings → Secrets.
2. New secret: name `MIRROR_SIGN_KEY_B64`, value = base64-encoded Ed25519 PEM (no newlines, no header/footer).
3. Scope: repository (or environment-specific if needed).
4. Save. The pipeline step will skip if the secret is empty; keep it present in release branches only.

## Local dry-run with test key
```
MIRROR_SIGN_KEY_B64=$(base64 -w0 out/mirror/thin/tuf/keys/mirror-ed25519-test-1.pem) \
OCI=1 scripts/mirror/ci-sign.sh
```

## Temporary dev key (to unblock CI until production key is issued)
Use this throwaway Ed25519 key only for non-production runs. Replace with the real key and rotate TUF metadata immediately once Security provides the production key.

```
MIRROR_SIGN_KEY_B64=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
```

**Do not ship with this key.** Set `REQUIRE_PROD_SIGNING=1` for release/tag builds so they fail without the real key.

## Verification
The CI step already runs `scripts/mirror/verify_thin_bundle.py`. For OCI, ensure `out/mirror/thin/oci/index.json` references the manifest digest.

## Fallback (if secret absent)
- CI can fall back to an embedded test Ed25519 key when `MIRROR_SIGN_KEY_B64` is unset **only when `REQUIRE_PROD_SIGNING` is not set**. This is for dev smoke runs; release/tag jobs must set `REQUIRE_PROD_SIGNING=1` to forbid fallback.
- For release branches, always set `REQUIRE_PROD_SIGNING=1` and provide `MIRROR_SIGN_KEY_B64`; otherwise the step will fail early.