dsfx/docs/requirements/nfr-5-audibility-and-transparency.md

# NFR-5: Auditability & Transparency

## 1. Overview

This document defines the requirements necessary to guarantee that all system operations are fully auditable and transparent. The objective is to build trust in the system by ensuring that every user action, file operation, and inter-node communication is logged in a tamper-evident manner. These logs provide a verifiable history for forensic analysis, regulatory compliance, and user accountability.

## 2. Objectives & Scope

### 2.1 Objectives

- **Immutable Logging:**
  Record all critical operations in an append-only, tamper-evident log.

- **Action Traceability:**
  Ensure that every action, permission change, or file operation is traceable to its origin (user, node, timestamp).

- **User Transparency:**
  Allow users to access audit logs to review system activity and verify that operations have been executed correctly.

- **Forensic Readiness:**
  Provide detailed logs that support forensic investigation and compliance with security standards.

### 2.2 Scope

- Applies to file operations (upload, download, encryption, decryption), replication events, access control changes, and inter-node communications.
- Encompasses logging mechanisms across client-side and server/node operations.
- Integrates with the immutable manifest design (ADR-0006) to ensure cryptographic chaining of logs.
- Covers both real-time monitoring and historical log retrieval capabilities.

## 3. Detailed Requirements

### 3.1 Logging Mechanisms

- **Append-Only Log Structure:**

  - Every critical operation must be logged with relevant details (timestamp, actor, operation details, outcomes).
  - Logs must be written in an immutable, append-only format and protected by cryptographic chaining.

- **Granularity of Logging:**
  - Define the level of detail required for each type of operation (e.g., file transfers, access changes, replication events).
  - Logs should include sufficient metadata to allow comprehensive reviews without revealing sensitive data.

### 3.2 Transparency and User Access

- **Audit Log Retrieval:**

  - Provide interfaces (CLI and future web UI) for users to query and review audit logs.
  - Allow users to filter logs by date, operation type, or actor.

- **Real-Time Alerts:**

  - Implement real-time monitoring that triggers alerts for suspicious or critical operations (e.g., unexpected access revocations, repeated failures).

- **Compliance Reporting:**
  - Support export formats for audit logs to facilitate external compliance reviews and security audits.

### 3.3 Integration with Other Modules

- **Immutable Manifest Integration:**

  - Integrate logging with the manifest to ensure that every change is recorded and verifiable.
  - Maintain consistency between audit logs and manifest snapshots for integrity.

- **Security and Key Management:**
  - Ensure that logs related to sensitive operations (e.g., key changes) are encrypted and access-controlled.

## 4. Measurable Criteria & Test Cases

### 4.1 Log Integrity Verification

- Regularly perform cryptographic verification of log chains to confirm that no tampering has occurred.
- Simulate unauthorized modifications to verify that the system detects breaches in log integrity.

### 4.2 User Audit Access Testing

- Conduct tests where users retrieve logs and verify that filtering and search functions return accurate results.
- Measure the performance of log retrieval operations under various loads.

### 4.3 Forensic Readiness Tests

- Test the export functionality to ensure that logs can be exported in standard, compliant formats.
- Validate that all audit events include complete metadata for forensic analysis.

## 5. Dependencies & Integration Points

- **Immutable Manifest System:**
  - Critical reliance on ADR-0006 for cryptographic chaining and tamper-evidence.
- **Access Control Systems:**
  - Integration with FR-6 and other access management functionalities to log all permission changes.
- **Monitoring Tools:**
  - Use of real-time monitoring systems to trigger alerts and collect log data continuously.

## 6. Conclusion

NFR-5 ensures that all system activities are transparent, traceable, and verifiable, providing a robust audit trail critical to user trust and regulatory compliance. Through immutable logging, detailed action traceability, and user-accessible audit reports, the system will be capable of robust forensic analysis and continuous security monitoring.