TG-DAL-ANCHOR
TrustGate DAL Anchor Engine
0. Identity
Depends on module:
1. Purpose
The TrustGate DAL Anchor Engine is responsible for converting finalized TrustGate runtime artifacts into cryptographically verifiable Digital Assurance Ledger (DAL) anchor records.
It receives anchor candidates from TrustGate engines, canonicalizes and hashes the referenced artifacts, groups records into Merkle batches where appropriate, submits anchor payloads to DAL, receives ledger references, and emits verification events back into the TrustGate runtime.
The engine provides the cryptographic bridge between TrustGate operations and the immutable assurance layer of ZAYAZ.
The core purpose is to ensure that every material TrustGate outcome can later be independently verified by auditors, regulators, federation participants, buyers, suppliers, and internal assurance teams.
2. Position within TrustGate Runtime
Trust Scoring
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Decision Engine
│
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Replay Engine
│
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Attestation Engine
│
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──────────────────────────────────────────
DAL Anchor Engine
──────────────────────────────────────────
│
├── Canonical Hash
├── Merkle Batch
├── DAL Submission
├── Ledger Reference
└── Inclusion Proof
The DAL Anchor Engine executes after one or more TrustGate artifacts have reached an anchorable state.
Anchorable artifacts include:
- trust score events;
- decision events;
- quarantine lifecycle events;
- replay manifests;
- replay results;
- trust attestations;
- federation packages;
- AI feedback events where policy requires anchoring;
- assurance evidence bundles.
3. Canonical Identity
| Property | Value |
|---|---|
| MEID | MEID_TRUST_ANCHOR_LEDGER |
| CMI | vera.TG-DAL.ENGINE.ANCHOR.1_0_0 |
| KIND | ENGINE |
| Owner Module | Verification & Assurance |
| Runtime Tier | Tier-0 Assurance Runtime |
| Engine Category | ANCHOR |
| Engine Domain | trust |
| ZAR Registration | Required |
| Replay Support | Native |
| DAL Anchoring | Native |
| Federation Aware | Yes |
The MEID identifies the stable logical ledger anchoring engine.
The CMI identifies this specific versioned implementation.
4. Runtime Responsibilities
| Responsibility | Description |
|---|---|
| Anchor Candidate Intake | Receive anchorable TrustGate artifacts from upstream engines. |
| Canonical Serialization | Convert artifacts into stable deterministic serialization. |
| Hash Generation | Compute cryptographic hashes over canonical payloads. |
| Merkle Batch Assembly | Group anchor candidates into Merkle batches when policy permits. |
| DAL Submission | Submit root hashes, batch metadata, and artifact metadata to DAL. |
| Verification Tracking | Receive and store DAL verification state and ledger references. |
| Proof Binding | Bind ledger references to TrustGate artifacts, USO lineage, replay manifests, and attestations. |
| Retry Handling | Safely retry failed submissions without duplicate anchoring. |
| Federation Readiness | Prepare DAL references for AFLE and EGFS exchange. |
| AII Telemetry | Emit DAL integrity metrics for Assurance Intelligence Index computation. |
The engine must not alter upstream artifacts. It only anchors canonicalized representations and returns ledger references.
5. Anchorable Artifact Types
| Artifact Type | Source Engine | DAL Required |
|---|---|---|
TrustScoreEvent | Trust Scoring Engine | Yes |
TrustDecisionEvent | Decision Engine | Yes |
TrustQuarantineEvent | Quarantine Manager | Yes |
TrustReplayManifest | Replay Engine | Yes |
TrustReplayResult | Replay Engine / OARM / AAE | Yes |
TrustAttestation | Attestation Engine | Yes |
FederationTrustPackage | Attestation / Federation Engine | Yes |
CarbonPassportTrustReference | Attestation Engine | Yes |
AITrustFeedbackEvent | AI Feedback Engine | Policy-based |
AuditReviewAction | Quarantine / OARM | Policy-based |
The canonical list should be maintained in ZAR and mirrored in the DAL artifact type registry.
6. Anchoring Model
The engine supports two anchoring modes.
| Mode | Description |
|---|---|
DIRECT_ANCHOR | Submits a single artifact hash directly to DAL. |
MERKLE_BATCH_ANCHOR | Groups multiple artifact hashes into a Merkle tree and submits the root hash. |
Direct anchoring is used for high-criticality events.
Merkle batch anchoring is used for high-volume operational events.
The default mode is policy-controlled by artifact type.
7. Hashing Model
The canonical artifact hash is calculated as:
For Merkle batches:
The engine must preserve:
- canonical payload hash;
- canonical serialization version;
- hash algorithm;
- artifact type;
- engine CMI;
- MEID;
- source ECO Number;
- USO reference;
- replay reference where applicable;
- policy context.
8. Runtime Processing Pipeline
Receive Anchor Candidate
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Validate Candidate
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Resolve Artifact Type Policy
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Canonicalize Payload
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Generate Artifact Hash
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Add to Direct Anchor or Merkle Batch
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Submit to DAL
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Receive Ledger Reference
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Bind Ledger Reference to Artifact
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Emit Verification Event
The pipeline must be idempotent.
If the same artifact hash is submitted twice, the engine must detect the existing ledger reference and avoid duplicate semantic anchoring.
9. Processing Algorithm
function anchor(candidate):
validate_candidate(candidate)
policy = resolve_anchor_policy(candidate.artifact_type)
canonical_payload = canonical_serialize(candidate.artifact)
artifact_hash = sha256(canonical_payload)
existing_ref = lookup_existing_anchor(artifact_hash)
if existing_ref exists:
emit_anchor_reused_event(existing_ref)
return existing_ref
if policy.mode == DIRECT_ANCHOR:
submission = create_direct_anchor(candidate, artifact_hash)
ledger_ref = submit_to_dal(submission)
if policy.mode == MERKLE_BATCH_ANCHOR:
batch = add_to_merkle_batch(candidate, artifact_hash)
ledger_ref = submit_batch_when_ready(batch)
bind_ledger_ref(candidate.artifact_id, ledger_ref)
emit_anchor_verified_event(ledger_ref)
return ledger_ref
The engine must be safe for retries, concurrency, and partial DAL outage scenarios.
10. CSI Contracts
10.1. Input CSIs
| CSI | Required | Purpose |
|---|---|---|
comp.DAL.INPUT.ANCHOR-CANDIDATE.v1_0 | Yes | Anchor candidate from TrustGate runtime engines. |
comp.TG.INPUT.TRUST-SCORE.v1_0 | Conditional | Trust score event to anchor. |
comp.TG.INPUT.TRUST-DECISION.v1_0 | Conditional | Decision event to anchor. |
comp.TG.INPUT.REPLAY-MANIFEST.v1_0 | Conditional | Replay manifest to anchor. |
comp.TG.INPUT.TRUST-ATTESTATION.v1_0 | Conditional | Attestation payload to anchor. |
comp.USO.INPUT.LINEAGE-REF.v1_0 | Yes | USO lineage reference. |
comp.FAGF.INPUT.POLICY-CONTEXT.v1_0 | Yes | Anchor policy and retention profile. |
10.2. Output CSIs
| CSI | Purpose |
|---|---|
comp.DAL.OUTPUT.LEDGER-REF.v1_0 | DAL ledger reference returned after anchoring. |
comp.DAL.OUTPUT.MERKLE-PROOF.v1_0 | Merkle inclusion proof where applicable. |
comp.TG.EVENT.DAL-ANCHOR-SUBMITTED.v1_0 | Anchor submission event. |
comp.TG.EVENT.DAL-ANCHOR-VERIFIED.v1_0 | Anchor verification event. |
comp.TG.EVENT.DAL-ANCHOR-FAILED.v1_0 | Anchor failure event. |
comp.AII.INPUT.DAL-TELEMETRY.v1_0 | AII DAL integrity telemetry. |
11. Canonical Anchor Candidate
{
"anchor_candidate_id": "TGAC-2026-00001472",
"artifact_type": "TrustDecisionEvent",
"artifact_id": "TGD-2026-00001472",
"eco_number": "ECO-A123",
"uso_id": "USO-98122",
"source_engine_cmi": "vera.TG-DECISION.ENGINE.ROUTER.1_0_0",
"source_meid": "MEID_TRUST_ROUTE_DECISION",
"artifact_payload_ref": "s3://zayaz-artifacts/trustgate/TGD-2026-00001472.json",
"policy_context": {
"policy_bundle": "FAGF-2026.2",
"anchor_profile": "critical_assurance_event_v1"
},
"created_at": "2026-06-25T12:50:11Z"
}
12. Canonical Ledger Reference
{
"ledger_ref": {
"ledger_id": "DAL-2026-001245",
"artifact_id": "TGD-2026-00001472",
"artifact_type": "TrustDecisionEvent",
"artifact_hash": "sha256:2f93ad...",
"anchor_mode": "MERKLE_BATCH_ANCHOR",
"root_hash": "sha256:7cc4b1...",
"batch_id": "DALB-2026-06-25-1200",
"verified": true,
"anchored_at": "2026-06-25T13:00:00Z"
}
}
13. Merkle Batch Record
{
"batch_id": "DALB-2026-06-25-1200",
"batch_window": {
"from": "2026-06-25T12:00:00Z",
"to": "2026-06-25T13:00:00Z"
},
"record_count": 158342,
"anchored_objects": [
"TrustScoreEvent",
"TrustDecisionEvent",
"TrustReplayManifest",
"TrustAttestation"
],
"root_hash": "sha256:7cc4b1...",
"hash_algorithm": "SHA-256",
"submitted_by": "vera.TG-DAL.ENGINE.ANCHOR.1_0_0"
}
The record_count and anchored_objects fields are required for operational transparency and audit-grade batch verification.
14. Merkle Inclusion Proof
{
"proof": {
"artifact_id": "TGD-2026-00001472",
"leaf_hash": "sha256:2f93ad...",
"merkle_path": [
{
"position": "left",
"hash": "sha256:d7c9..."
},
{
"position": "right",
"hash": "sha256:f9ab..."
}
],
"root_hash": "sha256:7cc4b1...",
"verified": true
}
}
Auditors may recompute the hash path to confirm inclusion in the anchored batch.
15. Anchor Submitted Event
{
"event_type": "trustgate.dal.anchor_submitted",
"anchor_candidate_id": "TGAC-2026-00001472",
"artifact_id": "TGD-2026-00001472",
"artifact_type": "TrustDecisionEvent",
"artifact_hash": "sha256:2f93ad...",
"anchor_mode": "MERKLE_BATCH_ANCHOR",
"engine_cmi": "vera.TG-DAL.ENGINE.ANCHOR.1_0_0",
"timestamp": "2026-06-25T13:00:00Z"
}
16. Anchor Verified Event
{
"event_type": "trustgate.dal.anchor_verified",
"artifact_id": "TGD-2026-00001472",
"ledger_id": "DAL-2026-001245",
"root_hash": "sha256:7cc4b1...",
"verified": true,
"proof_available": true,
"timestamp": "2026-06-25T13:00:09Z"
}
17. DAL Integration
The engine integrates directly with DAL services for:
- anchor submission;
- Merkle batch creation;
- ledger reference lookup;
- proof retrieval;
- anchor verification;
- failed anchor retry;
- external root synchronization.
The engine must treat DAL as the authoritative ledger system. TrustGate only prepares and submits anchor candidates.
18. Replay Behaviour
The anchor process must be replayable.
Replay inputs include:
- anchor candidate;
- canonical serialization version;
- artifact payload reference;
- artifact hash;
- batch policy;
- Merkle construction algorithm;
- DAL submission response;
- engine CMI.
Replay verification succeeds when:
For Merkle batches, replay also verifies:
19. Federation Behaviour
DAL references produced by this engine are used by AFLE and EGFS to validate TrustGate evidence across organizational boundaries.
Federation-safe ledger references must include:
| Field | Required |
|---|---|
| ECO Number | Yes |
| Artifact Type | Yes |
| Artifact Hash | Yes |
| Ledger ID | Yes |
| Root Hash | Yes |
| Merkle Proof | Conditional |
| Anchor Timestamp | Yes |
| Signature Metadata | Conditional |
Raw payloads must not be exported unless allowed by FAGF policy and federation profile.
20. AII Integration
DAL anchoring telemetry contributes to AII integrity dimensions.
{
"eco_number": "ECO-A123",
"period": "2026-Q2",
"anchor_candidates": 18440,
"anchors_submitted": 18440,
"anchors_verified": 18439,
"anchor_failure_rate": 0.00005,
"avg_anchor_latency_seconds": 62.4,
"merkle_batches": 12,
"dal_verification_rate": 0.99995
}
21. AI / DSAIL Integration
DAL anchoring outcomes may be consumed by DSAIL.
Useful learning signals include:
- anchor failure rate;
- delayed anchoring;
- repeated anchor retries;
- artifact type anomaly;
- ledger verification drift;
- federation proof failures.
AI may recommend:
- increased replay sampling;
- policy review;
- federation trust adjustment;
- batch size optimization;
- anomaly investigation.
AI may not suppress failed anchor events or modify ledger references.
22. Failure Handling
| Failure | Severity | Action |
|---|---|---|
| Missing anchor candidate | Critical | Abort |
| Missing artifact payload | Critical | Abort |
| Canonical serialization failure | Critical | Abort |
| Hash generation failure | Critical | Abort |
| DAL unavailable | Warning | Queue retry |
| Duplicate artifact hash | Info | Reuse existing ledger reference |
| Merkle batch timeout | Warning | Submit partial batch if policy permits |
| DAL verification failure | Critical | Escalate |
| Ledger proof unavailable | Warning | Mark proof pending |
| Federation export requested before verification | Critical | Block export |
The engine must fail closed for federation and external assurance use cases.
23. Observability Metrics
| Metric | Description |
|---|---|
tg_dal_anchor_candidate_total | Anchor candidates received. |
tg_dal_anchor_submitted_total | Anchors submitted to DAL. |
tg_dal_anchor_verified_total | Anchors verified by DAL. |
tg_dal_anchor_failed_total | Anchor failures. |
tg_dal_anchor_latency_seconds | Anchor submission-to-verification latency. |
tg_dal_merkle_batch_total | Merkle batches created. |
tg_dal_merkle_batch_record_count | Records per Merkle batch. |
tg_dal_duplicate_hash_total | Duplicate hashes reused. |
tg_dal_retry_total | Retry attempts. |
24. Performance Targets
| Metric | Target |
|---|---|
| Anchor candidate validation latency | < 20 ms |
| Hash generation latency | < 10 ms per artifact |
| Batch assembly latency | < 100 ms |
| Direct anchor submission latency | < 2 sec |
| Merkle batch window | Policy-defined, default 60 min |
| Throughput | 100,000 anchor candidates/min per worker pool |
| Verification availability | 99.99% |
| Hash determinism | 100% |
25. Security Requirements
The engine must:
- use approved hash algorithms;
- preserve canonical serialization rules;
- prevent payload mutation after hashing;
- enforce identity and service authentication;
- prevent unauthorized anchor submission;
- redact sensitive payload details from logs;
- store only hashes and references unless policy permits payload storage;
- record MEID and CMI in every anchor event;
- verify DAL responses;
- protect against replay attacks and duplicate semantic anchors.
26. Compliance Alignment
| Framework | DAL Anchor Engine Contribution |
|---|---|
| CSRD | Supports tamper-evident audit trails for sustainability data. |
| ESRS | Supports evidence traceability and assurance transparency. |
| ISSB / IFRS S1-S2 | Supports investor-grade data integrity controls. |
| ISO 14064-1 | Supports GHG verification and chain-of-custody evidence. |
| ISO 27001 | Supports integrity, logging, and cryptographic controls. |
| W3C DID / VC | Supports verifiable trust evidence exchanged across federation. |
27. Developer Implementation Notes
Developers should implement the DAL Anchor Engine as an idempotent, event-driven anchoring service.
Recommended design:
- anchor candidate queue;
- canonical serialization library;
- hash generator;
- Merkle batch builder;
- duplicate hash detector;
- DAL submission adapter;
- ledger reference binder;
- verification listener;
- retry scheduler;
- proof retrieval service;
- AII telemetry publisher.
The engine should never mutate source artifacts. All operations must reference immutable payloads and hashes.
28. Summary
The TrustGate DAL Anchor Engine provides the cryptographic integrity layer for TrustGate outcomes.
It ensures that TrustGate scores, decisions, replay artifacts, quarantine events, and attestations become tamper-evident, independently verifiable, and federation-ready through DAL.
No TrustGate artifact should be used for external assurance, federation exchange, Carbon Passport reference, or regulatory disclosure unless it has a DAL ledger reference or an explicit policy exception.