Log

The transparency log: sequenced Merkle commitments (RFC 6962, Confium constants) with signed inclusion receipts, monotonic signed tree heads, and optional RFC 3161 external anchoring. In the reference deployment it binds 127.0.0.1:8392 as log unidpp-pilot-log-1.

Deliberately absent: any enumeration surface. There is no endpoint that lists subjects or commitments — a transparency log is verifiable without being browsable. The journal file and receipts are the audit interfaces.

Endpoints

Endpoint	What
GET /	discovery: the operator public key, invariants, verification recipe, quorum statement
GET /healthz	liveness
POST /commitments	sequence {subject, commitment (64-hex), salt_ref?} → the signed inclusion receipt
GET /tree/head	the latest signed tree head (append-time checkpoint, monotonic)
GET /tree/consistency?from=N	RFC 6962 consistency proof from a pinned prefix to the current head
GET /receipt/{seq}	re-serve a receipt, byte-identical to the original POST /commitments response

Appending requires UNIDPP_LOG_APPEND_TOKEN when set (open in dev mode).

Example (recorded against the reference deployment)

$ curl -s http://127.0.0.1:8392/tree/head | jq '{tree_size, root: .root[0:16], log_id}'
{
  "tree_size": 5,
  "root": "d23b199b96ed73ea",
  "log_id": "unidpp-pilot-log-1"
}

$ curl -s http://127.0.0.1:8392/receipt/0 | jq '{seq, subject, log_id}'
{
  "seq": 0,
  "subject": "urn:unidpp:archive:snapshot:s-000000000000",
  "log_id": "unidpp-pilot-log-1"
}

The discovery document publishes the operator key (id, suite, public key hex, fingerprint) — pin it alongside the log id.

Verifying a receipt

The recipe, from the discovery document:

1. Verify tree_head.signature against the operator public key (from GET /).
2. Verify the inclusion proof reconstructs tree_head.root from the anchored commitment.
3. As the tree grows, GET /tree/consistency?from=<receipt tree_size> and verify it ties the receipt’s pinned root to the current head.

Invariants: sequence numbers are strictly monotonic; heads are signed at append time over tree_size + root + timestamp and never move backwards; no enumeration (see above). Quorum today is M=1 of K=1 — one honest operator — with the documented succession path (M-of-K log-of-logs; the master-list verification already exists in the trust service).

Environment

Manifest-rendered:

Variable	Meaning	Default
UNIDPP_LOG_BIND	listen address	127.0.0.1:8092
UNIDPP_LOG_APPEND_TOKEN	Bearer token for appends; unset = open	unset
UNIDPP_LOG_STATE_FILE	append-only JSONL journal (replayed on start)	none
UNIDPP_LOG_ID	the log identity, 1-64 printable ASCII	unidpp-log-1
UNIDPP_LOG_EXTERNAL_TSA_URL	RFC 3161 TSA endpoint; absent = no external anchoring	none

Direct environment:

Variable	Meaning	Default
UNIDPP_LOG_SUITE	operator signing suite	ed25519
UNIDPP_LOG_SEED	deterministic operator key seed (production identity)	documented dev seed

Degradation semantics

• TSA anchoring degrades explicitly. Every append’s tree head is also submitted to the TSA when configured; an unreachable or refusing TSA records the failure — the anchor is never silently skipped.
• Bad configuration exits loudly. A malformed UNIDPP_LOG_BIND is ignored with a warning; an invalid log id or suite prevents startup.
• Journal replay discipline. The journal replays with the same monotonic-sequencing checks it appends with; a torn tail stops replay at the last whole record.
• On a sovereign deployment, a configured TSA URL under a none egress policy is refused at manifest validation — before anything runs.