# Offline Kit Import and Attestation Verification

## Module
Scanner

## Status
IMPLEMENTED

## Description
Offline kit import service and offline attestation verifier with test coverage in Scanner module, enabling verification of DSSE-signed attestations without network access.

## Implementation Details
- **Offline Kit Import**:
  - `src/Scanner/StellaOps.Scanner.WebService/Services/OfflineKitImportService.cs` - `OfflineKitImportService` imports offline vulnerability data kits
  - `src/Scanner/StellaOps.Scanner.WebService/Services/OfflineKitManifestService.cs` - `OfflineKitManifestService` manages offline kit manifests
  - `src/Scanner/StellaOps.Scanner.WebService/Services/OfflineKitContracts.cs` - Contract models for offline kit operations
  - `src/Scanner/StellaOps.Scanner.WebService/Services/OfflineKitStateStore.cs` - State tracking for imported kits
  - `src/Scanner/StellaOps.Scanner.WebService/Services/OfflineKitMetricsStore.cs` - Metrics tracking for import operations
- **Attestation Verification**:
  - `src/Scanner/StellaOps.Scanner.WebService/Services/IOfflineAttestationVerifier.cs` - `IOfflineAttestationVerifier` interface for verifying DSSE-signed attestations offline
  - `src/Scanner/StellaOps.Scanner.WebService/Services/OfflineAttestationVerifier.cs` - `OfflineAttestationVerifier` verifies DSSE signatures without network access using local trust anchors
  - `src/Scanner/StellaOps.Scanner.WebService/Services/NullOfflineKitAuditEmitter.cs` - Null audit emitter for environments without audit logging
- **API Endpoints**:
  - `src/Scanner/StellaOps.Scanner.WebService/Endpoints/OfflineKitEndpoints.cs` - REST endpoints for importing and managing offline kits
- **Configuration**:
  - `src/Scanner/__Libraries/StellaOps.Scanner.Core/Configuration/OfflineKitOptions.cs` - `OfflineKitOptions` configuration model
  - `src/Scanner/__Libraries/StellaOps.Scanner.Core/Configuration/OfflineKitOptionsValidator.cs` - Options validation
- **Trust Anchors**:
  - `src/Scanner/__Libraries/StellaOps.Scanner.Core/TrustAnchors/TrustAnchorRegistry.cs` - `TrustAnchorRegistry` manages local trust anchors for offline verification

## E2E Test Plan
- [ ] Import an offline vulnerability kit via the `OfflineKitEndpoints` and verify it is accepted and stored
- [ ] Verify DSSE-signed attestations within the kit are verified using local trust anchors without network access
- [ ] Verify import of a tampered kit fails attestation verification
- [ ] Verify kit manifest service correctly lists available kits and their status
- [ ] Verify offline kit state tracking records import timestamps and kit versions
- [ ] Verify the scanner operates correctly with offline kit data as its vulnerability source