# HSM Integration (PKCS#11)

## Module
Cryptography

## Status
VERIFIED

## Description
PKCS#11 HSM client implementation for hardware security module integration, with integration tests.

## Implementation Details
- **HsmPlugin**: `src/Cryptography/StellaOps.Cryptography.Plugin.Hsm/HsmPlugin.cs` -- HSM crypto plugin extending CryptoPluginBase; supports algorithms: HSM-RSA-SHA256/384/512, HSM-RSA-PSS-SHA256, HSM-ECDSA-P256/P384, HSM-AES-128/256-GCM; initializes with PKCS#11 library path (or simulation mode when unconfigured); SignAsync/VerifyAsync/EncryptAsync/DecryptAsync delegate to IHsmClient; HashAsync (SHA-256/384/512) computed locally; health check reports connected/disconnected/degraded status with slot info
- **IHsmClient**: `src/Cryptography/StellaOps.Cryptography.Plugin.Hsm/HsmPlugin.cs` -- HSM client interface: ConnectAsync (slotId, pin), DisconnectAsync, PingAsync, SignAsync, VerifyAsync, EncryptAsync, DecryptAsync
- **Pkcs11HsmClientImpl**: `src/Cryptography/StellaOps.Cryptography.Plugin.Hsm/Pkcs11HsmClientImpl.cs` -- production PKCS#11 client implementation wrapping native PKCS#11 library
- **Pkcs11HsmClient**: `src/Cryptography/StellaOps.Cryptography.Plugin.Hsm/HsmPlugin.cs` -- adapter delegating to Pkcs11HsmClientImpl with connection management
- **SimulatedHsmClient**: `src/Cryptography/StellaOps.Cryptography.Plugin.Hsm/HsmPlugin.cs` -- test double for HSM operations without hardware: generates RSA-2048 + AES-256 keys on connect; RSA sign/verify with PKCS1/PSS padding; AES-GCM encrypt/decrypt with IV + tag management
- **HsmOptions**: `src/Cryptography/StellaOps.Cryptography.Plugin.Hsm/HsmPlugin.cs` -- configuration: LibraryPath (.so/.dll path, empty for simulation), SlotId, Pin, TokenLabel, ConnectionTimeoutSeconds (30), ReadOnlySession flag
- **HsmMechanism**: enum for signing/encryption mechanism mapping: RsaSha256/384/512, RsaPssSha256, EcdsaP256/P384, Aes128Gcm, Aes256Gcm
- **Tests**: `src/Cryptography/__Tests/StellaOps.Cryptography.Tests/Hsm/Pkcs11HsmClientIntegrationTests.cs`, `SoftHsmTestFixture.cs`
- **Source**: Feature matrix scan

## E2E Test Plan
- [x] Verify HSM plugin initializes in simulation mode when no library path is configured
- [x] Verify HSM plugin connects to PKCS#11 library when LibraryPath is set
- [x] Test RSA signing and verification with SHA-256/384/512 and PKCS1/PSS padding
- [x] Test ECDSA P-256 and P-384 signing and verification
- [x] Test AES-128-GCM and AES-256-GCM encryption and decryption
- [x] Verify health check returns Unhealthy when not connected, Degraded on slow response, Healthy with slot details
- [x] Verify CanHandle only accepts algorithms with HSM- prefix
- [x] Test plugin lifecycle: initialize -> active -> health check -> dispose (disconnect)

## Verification
Run ID: run-001
Date: 2026-02-10
Method: Tier 1 code review + Tier 2d test verification

Build: PASS (0 errors, 0 warnings)
Tests: PASS (101/101 cryptography tests pass)

Pkcs11HsmClientImpl is a 723-line production implementation using Pkcs11Interop with session pooling (SlotContext with ConcurrentBag), multi-slot failover with health monitoring, key search by CKA_LABEL or CKA_ID, key attribute validation. SimulatedHsmClient provides functional RSA+AES operations for testing. SoftHSM2 integration tests.

Verdict: PASS

## Recheck (Run-002)
- **Verified**: 2026-02-10
- **Method**: Tier 2d deterministic integration replay.
- **Tests**: PASS (`src/Cryptography/__Tests/StellaOps.Cryptography.Tests`: 101/101).
- **Tier 2 Evidence**: `docs/qa/feature-checks/runs/cryptography/hsm-integration/run-002/tier2-integration-check.json`
- **Outcome**: PKCS#11 integration behavior remains stable with existing SoftHSM safeguards.

## Recheck (Run-003)
- **Verified**: 2026-02-10
- **Method**: Tier 2 follow-up deterministic integration replay.
- **Tests**: PASS (`src/Cryptography/__Tests/StellaOps.Cryptography.Tests`: 101/101).
- **Tier 2 Evidence**: `docs/qa/feature-checks/runs/cryptography/hsm-integration/run-003/tier2-integration-check.json`
- **Outcome**: HSM integration paths remain stable with existing SoftHSM safeguards.


## Recheck (Run-004)
- **Verified**: 2026-02-10
- **Method**: Tier 2 deterministic integration replay + full cryptography suite replay.
- **Tests**: PASS (`src/Cryptography/__Tests/StellaOps.Cryptography.Tests`: 101/101).
- **Tier 2 Evidence**: `docs/qa/feature-checks/runs/cryptography/hsm-integration/run-004/tier2-integration-check.json`
- **Outcome**: Checked cryptography behavior remains stable; PQC caveat remains unchanged.

## Recheck (Run-005)
- **Verified**: 2026-02-10
- **Method**: Tier 2d deterministic integration replay.
- **Tests**: PASS (src/Cryptography/__Tests/StellaOps.Cryptography.Tests: 101/101).
- **Tier 2 Evidence**: docs/qa/feature-checks/runs/cryptography/hsm-integration/run-005/tier2-integration-check.json
- **Outcome**: Checked cryptography behavior remains healthy in follow-up replay.

## Recheck (Run-006)
- **Verified**: 2026-02-10
- **Method**: Tier 2d deterministic integration replay.
- **Tests**: PASS (src/Cryptography/__Tests/StellaOps.Cryptography.Tests: 101/101).
- **Tier 2 Evidence**: docs/qa/feature-checks/runs/cryptography/hsm-integration/run-006/tier2-integration-check.json
- **Outcome**: Checked cryptography behavior remains healthy in continued replay.

## Recheck (Run-007)
- **Verified**: 2026-02-10
- **Method**: Tier 2d deterministic integration replay.
- **Tests**: PASS (src/Cryptography/__Tests/StellaOps.Cryptography.Tests: 101/101).
- **Tier 2 Evidence**: docs/qa/feature-checks/runs/cryptography/hsm-integration/run-007/tier2-integration-check.json
- **Outcome**: Checked cryptography behavior remains healthy in continued replay.

## Recheck (Run-008)
- **Verified**: 2026-02-10
- **Method**: Tier 2d deterministic integration replay.
- **Tests**: PASS (src/Cryptography/__Tests/StellaOps.Cryptography.Tests: 101/101).
- **Tier 2 Evidence**: docs/qa/feature-checks/runs/cryptography/hsm-integration/run-008/tier2-integration-check.json
- **Outcome**: Checked cryptography behavior remains healthy in continued replay.


## Recheck (Run-009)
- **Verified**: 2026-02-10
- **Method**: Tier 2d deterministic integration replay.
- **Tests**: PASS (src/Cryptography/__Tests/StellaOps.Cryptography.Tests: 101/101).
- **Tier 2 Evidence**: docs/qa/feature-checks/runs/cryptography/hsm-integration/run-009/tier2-integration-check.json
- **Outcome**: Checked cryptography behavior remains healthy in continued replay.
## Recheck (Run-010)
- **Verified**: 2026-02-10
- **Method**: Tier 2d deterministic integration replay.
- **Tests**: PASS (src/Cryptography/__Tests/StellaOps.Cryptography.Tests: 101/101).
- **Tier 2 Evidence**: docs/qa/feature-checks/runs/cryptography/hsm-integration/run-010/tier2-integration-check.json
- **Outcome**: Checked cryptography behavior remains healthy in continued replay.
## Recheck (Run-011)
- **Verified**: 2026-02-10
- **Method**: Tier 2d deterministic integration replay.
- **Tests**: PASS (src/Cryptography/__Tests/StellaOps.Cryptography.Tests: 101/101).
- **Tier 2 Evidence**: docs/qa/feature-checks/runs/cryptography/hsm-integration/run-011/tier2-integration-check.json
- **Outcome**: Checked cryptography behavior remains healthy in continued replay.
## Recheck (Run-012)
- **Verified**: 2026-02-10
- **Method**: Tier 2d deterministic cryptography suite replay.
- **Tests**: PASS (src/Cryptography/__Tests/StellaOps.Cryptography.Tests: 101/101).
- **Tier 2 Evidence**: docs/qa/feature-checks/runs/cryptography/hsm-integration/run-012/tier2-integration-check.json
- **Outcome**: Checked cryptography behavior remains healthy in continued replay.