Court Grade Admissibility

Court-Grade Admissibility

Version: 1.3  |  PR: #184

Court-grade admissibility is the hardening layer that makes sealed governance artifacts verifiable by third parties without live system access. It composes six independent capabilities into a single seal_and_prove pipeline.

---

Admissibility Levels

Level	Name	What It Proves
L0	Audit Clean	Structural integrity — all required keys present, schema valid
L1	Deterministic	Same inputs + clock = same commit_hash every time
L2	Signed	Cryptographic authenticity — HMAC-SHA256 or Ed25519
L3	Logged	Tamper-evident record — hash-chained transparency log
L4	Committed	Merkle-bound — four independent commitment roots
L5	Witnessed	Multi-party attestation — threshold signatures from distinct keys
L6	Hardware-Backed	Key attestation — at least one hardware/external signer

---

Pipeline

The seal_and_prove.py orchestrator executes in order:

flowchart TD
    A[Find Decision] --> B[Build Sealed Run]
    B --> C[Embed Merkle Commitments]
    C --> D[Write Sealed + Manifest]
    D --> E[Sign Primary Signature]
    E --> F{Witness Keys?}
    F -- yes --> G[Append Witness Sigs]
    F -- no --> H[Append to Transparency Log]
    G --> H
    H --> I[Determinism Audit]
    I --> J[Replay Self-Check]
    J --> K{Pack Dir?}
    K -- yes --> L[Assemble Pack]
    K -- no --> M[Done]
    L --> M

Loading

One command:

python src/tools/reconstruct/seal_and_prove.py \
    --decision-id DEC-001 \
    --clock 2026-02-21T00:00:00Z \
    --sign-algo hmac \
    --sign-key-id ds-dev-2026-02 \
    --sign-key "$DEEPSIGMA_SIGNING_KEY" \
    --pack-dir /tmp/admissibility-pack

---

Components

Merkle Commitments

Four independent Merkle trees bind inputs, prompts, schemas, and policies:

graph TD
    subgraph Inputs Tree
        I1[CSV 1 hash] --> IR[inputs_root]
        I2[CSV 2 hash] --> IR
        I3[CSV N hash] --> IR
    end
    subgraph Prompts Tree
        P1[prompt 1 hash] --> PR[prompts_root]
        P2[prompt N hash] --> PR
    end
    subgraph Schemas Tree
        S1[schema 1 hash] --> SR[schemas_root]
        S2[schema N hash] --> SR
    end
    subgraph Policies Tree
        PO1[policy hash] --> POR[policies_root]
    end
    IR --> SC[inputs_commitments]
    PR --> SC
    SR --> SC
    POR --> SC
    SC --> SEALED[Sealed Run]

Loading

Key property: roots are derived from the same leaf hashes in hash_scope, so replay can recompute and verify without accessing original files.

Transparency Log

Append-only NDJSON file (artifacts/transparency_log/log.ndjson). Each entry chains to the previous via prev_entry_hash, creating a tamper-evident linked list:

Entry 1: prev=null, hash=abc...
Entry 2: prev=abc..., hash=def...
Entry 3: prev=def..., hash=ghi...

Tampering any entry invalidates all subsequent entries.

Multi-Signature Witness

Signatures start as a single signature_block_v1, then evolve into a multisig_block_v1 when --append is used:

Scenario	Format	Threshold
Single operator	sig_version: 1.0	1
Operator + reviewer	multisig_version: 1.0	2
Operator + reviewer + auditor	multisig_version: 1.0	3

Each signature carries signer_id, role, and signer_type (software/hardware/external).

Hardware-Backed Keys

The --external-signer-cmd flag delegates signing to an external process (YubiKey, HSM, KMS):

1. Payload hash written to temp file
2. Command invoked with temp file path as argument
3. Base64 signature read from stdout

Determinism Audit

9 checks verify a sealed run is fully deterministic:

1. hash_scope.present
2. hash_scope.clock_fixed
3. hash_scope.deterministic_flag
4. exclusions.observed_at
5. ids.run_id_deterministic
6. ids.no_uuid
7. timestamps.committed_at_matches_clock
8. commitments.present
9. canonical.json_valid

---

Verification (Auditor Workflow)

# Step 1: Replay (structure + hash + commitments)
python src/tools/reconstruct/replay_sealed_run.py --sealed <file>.json

# Step 2: Verify signature
python src/tools/reconstruct/replay_sealed_run.py --sealed <file>.json \
    --verify-signature true --key <key>

# Step 3: Verify transparency log
python src/tools/reconstruct/replay_sealed_run.py --sealed <file>.json \
    --verify-transparency true --transparency-log log.ndjson

# Step 4: Require multi-sig threshold
python src/tools/reconstruct/replay_sealed_run.py --sealed <file>.json \
    --require-multisig 2 --key <key>

# Step 5: Determinism audit
python src/tools/reconstruct/determinism_audit.py --sealed <file>.json --strict

---

New Schemas

Schema	Purpose
merkle_commitment_v1.json	Four-root merkle commitment structure
multisig_block_v1.json	Threshold multi-signature envelope
transparency_log_entry_v1.json	Hash-chained log entry
timestamp_block_v1.json	Trusted timestamp (local + future RFC 3161)

---

CI Workflows

Workflow	What it tests
admissibility_gate.yml	Full pipeline: seal_and_prove + transparency chain + replay + audit
determinism_gate.yml	Two-run idempotency + determinism audit
signature_gate.yml	Sign + verify + tamper detection

---

Related Pages

• Sealing & Episodes — core sealing primitive
• Replay & Testing — adversarial replay harness
• Verifiers — postcondition checks
• Schemas — full schema index
• Mermaid Diagrams — visual diagrams