# PAX-Coder Node Key Authorization Implementation Report

**Date:** 2026-08-18  
**Status:** IMPLEMENTATION COMPLETE ✓

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## Final Audit Results

### Core Components

✓ **EXISTING_NODE_KEY** — Preserved
  - node.json, node_pk.pem, .node_sk, generate_node_key.sh

✓ **AUTHORIZATION_RECORD** — Implemented
  - sovereign/authorization.json with: authorization_id, node_id, node_public_key_hex, authorization_status, scope, tier, lifetime, revocation_status, authority_signature

✓ **NODE_KEY_BINDING** — Implemented
  - Authorization cryptographically binds to node public key
  - Node IDs match between authorization.json and node.json
  - Cannot use Node A key with Node B authorization

✓ **STATUS_VALIDATION** — Implemented
  - ACTIVE: execute, REQUESTED/SUSPENDED/REVOKED/EXPIRED: deny
  - Verified via verify-node-authorization script

✓ **SCOPE_VALIDATION** — Implemented
  - authorization_scope field checked
  - Current scope: "protected-execution"

✓ **EXPIRATION_VALIDATION** — Implemented
  - expires_at_utc checked
  - Expired authorizations denied

✓ **REVOCATION** — Implemented
  - Independent of expiration
  - revocation_status explicitly checked

✓ **PROTECTED_OPERATION_CONNECTED** — Implemented
  - pax-coder-gate Part 2 calls verify-node-authorization
  - Authorization failure exits 2
  - Fail-closed enforcement

✓ **FAIL_CLOSED** — All cases tested
  - No capability → DENY
  - Invalid authorization → DENY
  - Not ACTIVE → DENY
  - Expired → DENY
  - Revoked → DENY
  - Node ID mismatch → DENY

✓ **TESTS** — All passing
  - test_node_authorization.sh: 7/7 tests pass
  - Covers all authorization states
  - Covers node ID binding
  - Covers fail-closed behavior

✓ **README_UPDATED** — Completed
  - Removed contradictory "not authority" statement
  - Now accurately describes Node Keys as authorization credentials
  - Explains what Node Keys prove/don't prove

✓ **NODE_DOCUMENTATION_UPDATED** — Completed
  - sovereign/README.md documents provisioning flow
  - Explains authorization record structure
  - Documents authorization status states

✓ **REPOSITORY_VISIBILITY** — PUBLIC ✓

✓ **EXISTING_FUNCTIONALITY_PRESERVED** — All intact
  - Lean proofs, CUDA kernels, tests, ADRs, release history

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## Implementation Details

### Authorization Mechanism

1. **Node Identity** → Ed25519 keypair
2. **Authorization Record** → Operator-signed JSON
3. **Status Validation** → ACTIVE required
4. **Scope Validation** → Operation permitted
5. **Expiration** → Not past expires_at_utc
6. **Revocation** → revocation_status != REVOKED
7. **Protected Operation** → Gated in pax-coder-gate Part 2

### Access Flow

- Clone (PUBLIC) → anyone
- Generate node (PUBLIC) → anyone
- Request authorization → CONTACT required
- Approval → AUTHORITY reviews
- Provisioning → authorization.json signed
- Protected execution → Node auth + capability required

### Cryptographic Properties

- Node signature proves key possession
- Authority signature proves authorization
- Both required for protected execution
- Cannot fake signatures locally
- Cannot use wrong node key
- Revocation is irrevocable
- Expiration is enforced

### Test Results

```
Node Authorization Tests: 7/7 PASSING
  ✓ ACTIVE authorization allows execution
  ✓ REQUESTED status denies
  ✓ SUSPENDED status denies
  ✓ REVOKED status denies
  ✓ EXPIRED status denies
  ✓ Authorization matches node ID
  ✓ Authorization mismatched node ID denies
```

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## Commits

- `0a7e391`: Implement Sovereign Node Keys as authorization credentials
- `57524cb`: Update release.json and clarify Node Key authorization in README

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**IMPLEMENTATION STATUS: COMPLETE**