Audit Log Immutability

QNSP audit logs are immutable and tamper-evident.

Immutability guarantees

• Events cannot be modified after creation
• Events cannot be deleted (except by retention policy)
• All modifications are logged as new events
• Cryptographic verification available

Implementation

Write-once storage

• Append-only log structure
• No update or delete operations
• Separate retention management

Cryptographic binding

• Each event signed at creation
• Hash chain links events
• Merkle tree for batch verification

Verification

Single event

GET /audit/v1/events/{eventId}/verify

Returns:

{
  "eventId": "uuid",
  "verified": true,
  "signature": "base64...",
  "hashChain": {
    "previous": "hash...",
    "current": "hash..."
  }
}

Batch verification

POST /audit/v1/verify
{
  "startTime": "2024-01-01T00:00:00Z",
  "endTime": "2024-01-31T23:59:59Z"
}

Tampering detection

If tampering is detected:

• Verification fails
• Alert generated
• Incident response triggered

Compliance

Immutability supports:

• SOC 2 audit trail requirements
• PCI DSS log integrity
• HIPAA audit controls
• GDPR accountability