# Zastava schemas (runtime & admission)

## Canonicalisation & hashing
- JSON is stored with sorted keys and two-space indentation; hashes use **JCS-style** encoding: `json.dumps(payload, separators=(',', ':'), sort_keys=True)`.
- `payload_hash` fields in examples and exports are computed from the canonical payload bytes and formatted as `sha256:<hex>`.
- Schema negotiation stays on the `zastava.*@v1.x` line; breaking changes bump the major version.

## DSSE signing
- Payload types:
  - `application/vnd.stellaops.zastava.schema+json;name=observer_event;version=1`
  - `application/vnd.stellaops.zastava.schema+json;name=webhook_admission;version=1`
- Ed25519 public key (base64url, no padding): `mpIEbYRL1q5yhN6wBRvkZ_0xXz3QUJPueJJ8sn__GGc`.
- Signatures are emitted as `<file>.dsse` with DSSEv1 pre-auth encoding over the raw file bytes.
- Regenerate signatures with `docs/modules/zastava/kit/verify.sh` prerequisites (Python + cryptography) and the private key held offline.

## Test vectors
- Example payloads: `schemas/examples/*.json`.
- Signed exports: `exports/observer_events.ndjson(.dsse)` and `exports/webhook_admissions.ndjson(.dsse)`.
- Kit verification aggregates all signatures via `kit/verify.sh`.