# KNEL-Football Secure OS - Product Requirements Document (PRD)

**Version:** 1.0
**Status:** Active
**Copyright:** © 2026 Known Element Enterprises LLC
**License:** GNU Affero General Public License v3.0 only
**Last Updated:** 2026-02-19

---

## Executive Summary

KNEL-Football Secure OS is a hardened Debian 13 Linux distribution designed for secure tier0 infrastructure access. The system implements a defense-in-depth security architecture with full disk encryption as a mandatory requirement, ensuring data protection against physical access attacks and unauthorized disclosure.

### Key Differentiators

- **Mandatory Full Disk Encryption (FDE)** - LUKS-based encryption for all system storage
- **Network Isolation** - VPN-only access with WireGuard
- **Minimal Attack Surface** - Only essential services and applications
- **Hardware Disabled** - WiFi and Bluetooth permanently disabled
- **Immutable Configuration** - Package management disabled by default
- **Privacy-Focused** - No telemetry, no user data collection

### System Architecture

**IMPORTANT CLARIFICATION**: KNEL-Football OS serves as a **secure remote terminal** for accessing tier0 infrastructure. It does NOT directly access tier0 infrastructure itself.

**Architecture**:
```
┌─────────────────┐
│ KNEL-Football OS│  ← Secure workstation with FDE
│ (Remote Terminal)│
└────────┬──────────┘
         │
         │ SSH/WireGuard
         │
         ▼
┌─────────────────┐
│ Privileged Access │  ← Physical workstation in secure facility
│   Workstation   │
└────────┬──────────┘
         │
         │ Direct Access
         │
         ▼
┌─────────────────┐
│  Tier0 Network │  ← Protected infrastructure
│   Infrastructure│
└─────────────────┘
```

**Access Model**:
1. User boots KNEL-Football OS on secure laptop (FDE required)
2. OS connects via WireGuard VPN to secure network
3. User uses SSH/Remmina to access privileged workstation
4. Privileged workstation (physical) accesses tier0 infrastructure
5. No direct tier0 access from KNEL-Football OS

This creates a **two-factor security model**:
- **Factor 1**: Physical possession of KNEL-Football OS workstation
- **Factor 2**: Access to privileged workstation in secure facility

---

## Product Vision

To provide the most secure, compliant, and user-friendly operating system for tier0 infrastructure access, protecting sensitive data and systems through comprehensive encryption, network isolation, and defense-in-depth security controls.

---

## Product Scope

### In Scope

- Full disk encryption (LUKS) for all storage devices
- Debian 13 base system with security hardening
- IceWM desktop environment
- WireGuard VPN client with QR code import
- Network firewall with default-deny policy
- SSH client for outbound remote access
- USB device automount with restrictions
- Automated ISO build process
- Comprehensive security testing suite

### Out of Scope

- General-purpose computing applications
- Internet browsing capabilities
- Application package manager
- Wireless networking support
- Bluetooth support
- Cloud storage integration
- Multi-user support (single-user system)

---

## Functional Requirements

### FR-001: Full Disk Encryption (MANDATORY)

**Priority:** P0 (Critical)
**Status:** Required

**Description:**
The system MUST implement full disk encryption using LUKS (Linux Unified Key Setup) to protect all data at rest. Encryption must be mandatory and cannot be bypassed during installation.

**Requirements:**
1. **LUKS2 Format** - Use LUKS2 with Argon2id key derivation
2. **AES-XTS Encryption** - AES-256-XTS cipher with 512-bit key size
3. **Boot Partition Encryption** - Root filesystem must be encrypted
4. **Separate Boot Partition** - Unencrypted /boot for bootloader (UEFI requirement)
5. **Key Recovery** - Support for multiple passphrases/key slots
6. **Integrity Protection** - Authenticated encryption or dm-integrity layer
7. **Secure Key Storage** - No plaintext keys stored anywhere on the system

**Encryption Passphrase Requirements (MANDATORY):**
- **Minimum Length**: 14 characters (20+ characters strongly recommended)
- **Character Classes**: Minimum 3 of 4 required:
  - Uppercase letters (A-Z) - At least 1 required
  - Lowercase letters (a-z) - At least 1 required
  - Digits (0-9) - At least 1 required
  - Special characters (!@#$%^&*) - At least 1 required
- **Prohibited Patterns**:
  - No common words (password, secret, admin, root, etc.)
  - No sequential characters (123, abc, qwerty)
  - No repeated characters (maximum 2 consecutive)
- **Security Notes**:
  - Passphrase is required at EVERY system boot
  - No backdoor or recovery mechanism without valid passphrase
  - Loss of passphrase = permanent data loss
  - Store passphrase in secure password manager

**Implementation Details:**
```
/dev/sda1    512M   EFI System Partition (ESP)
/dev/sda2    512M   /boot (ext4, unencrypted)
/dev/sda3    Remainder   LUKS2 encrypted partition
  └─ cryptroot    AES-256-XTS    / (ext4)
```

**Security Properties:**
- Data unreadable without correct passphrase
- No backdoors or recovery mechanisms by default
- Protected against cold boot attacks
- Protected against disk imaging attacks
- Compliant with NIST SP 800-111

### FR-002: Operating System Base

**Priority:** P0
**Status:** Required

**Requirements:**
1. **Base Distribution** - Debian 13 (Trixie) Testing
2. **Architecture** - AMD64 (x86_64) only
3. **Kernel** - Latest stable kernel with security patches
4. **Security Patches** - All available security patches applied
5. **Minimal Packages** - Only essential packages installed

### FR-003: Desktop Environment

**Priority:** P1
**Status:** Required

**Requirements:**
1. **Window Manager** - IceWM (minimal resource footprint)
2. **Display Manager** - LightDM with privacy mode
3. **Theme** - Dark, privacy-focused theme
4. **Applications** - Remmina (remote desktop), Mousepad (text editor)

**Privacy Features:**
- Hide usernames in login screen
- Disable guest account
- Disable auto-login
- Disable user list display

### FR-004: Network Isolation

**Priority:** P0
**Status:** Required

**Requirements:**
1. **WireGuard VPN** - Required for all network access
2. **No Direct Internet** - All traffic through VPN tunnel
3. **Firewall Rules** - Default deny, specific allow rules
4. **QR Code Import** - Easy VPN configuration import
5. **Dynamic Firewall** - Rules adapt to VPN endpoints

**Allowed Traffic:**
- WireGuard VPN traffic to configured endpoints
- DNS through VPN tunnel only
- Outbound through VPN interface only

### FR-005: Hardware Control

**Priority:** P0
**Status:** Required

**Requirements:**
1. **WiFi Disabled** - Permanently disabled via kernel module blacklist
2. **Bluetooth Disabled** - Permanently disabled via kernel module blacklist
3. **USB Restricted** - Controlled automount with security restrictions
4. **No Wireless Cards** - System should not have wireless hardware

**Blacklisted Modules:**
- WiFi: rtl*, iwl*, ath*, brcm*, mwifi*, rt2*
- Bluetooth: btusb, bluetooth

### FR-006: SSH Client (Outbound Only)

**Priority:** P1
**Status:** Required

**Requirements:**
1. **SSH Client Only** - No SSH server, no inbound SSH access
2. **Key-Based Authentication** - SSH keys for connecting to remote systems
3. **Hardened Client Config** - Modern ciphers, strict host key checking
4. **No Password Auth** - Public key authentication only for outbound connections
5. **Key Management** - Secure storage of user SSH private keys

**Important**: This system accepts NO inbound connections. SSH is client-only for initiating outbound connections to privileged access workstations.

### FR-007: System Hardening

**Priority:** P0
**Status:** Required

**Requirements:**
1. **Password Policy** - 14+ character minimum, complexity required
2. **Audit Logging** - Comprehensive system activity logging
3. **Resource Limits** - Prevent resource exhaustion attacks
4. **Service Hardening** - Disable unnecessary services
5. **Kernel Parameters** - Secure kernel parameter tuning

**Disabled Services:**
- avahi-daemon (zeroconf)
- cups (printing)
- bluetooth service
- NetworkManager (managed via scripts)

### FR-008: USB Device Handling

**Priority:** P1
**Status:** Required

**Requirements:**
1. **Automount Support** - Automatic USB device mounting
2. **Restricted Permissions** - No auto-execution
3. **User Mount Points** - /media/username/device
4. **Filesystem Support** - FAT32, exFAT, NTFS, ext4
5. **Audit Logging** - Track USB device insertion/removal

**Security Restrictions:**
- No automatic program execution
- No symbolic links from USB
- No device special files from USB
- Read-only mode for untrusted USB (optional)

### FR-009: System Immutability

**Priority:** P1
**Status:** Required

**Requirements:**
1. **Package Management Disabled** - No apt/dpkg commands for users
2. **Immutable Configuration** - Critical files have immutable attributes
3. **No Auto-Updates** - Updates via ISO rebuild only
4. **Configuration Tracking** - Detect configuration tampering

**Protected Directories:**
- /etc (system configuration)
- /usr (system binaries)
- /boot (bootloader)
- /bin, /sbin (essential binaries)

### FR-010: ISO Build Process

**Priority:** P1
**Status:** Required

**Requirements:**
1. **Reproducible Builds** - Identical outputs from identical inputs
2. **Docker-Based** - All build operations in Docker containers
3. **Checksum Verification** - SHA256 and MD5 checksums for ISO
4. **Build Logging** - Complete build audit trail
5. **Automated Testing** - Comprehensive test suite execution

**Build Artifacts:**
- ISO image (~1-2 GB)
- SHA256 checksum file
- MD5 checksum file
- Build report (optional)

### FR-011: Host System Full Disk Encryption (MANDATORY)

**Priority:** P0 (Critical)
**Status:** Required

**Description:**
The host system used to build or test KNEL-Football ISO images MUST have full disk encryption enabled. Building a secure operating system on an unencrypted host defeats the entire security model and creates a supply chain risk.

**Requirements:**
1. **LUKS Encryption Required** - Host must use LUKS for disk encryption
2. **Build Enforcement** - `./run.sh iso` command MUST fail if host FDE not detected
3. **VM Test Enforcement** - `./run.sh test:iso` commands MUST fail if host FDE not detected
4. **No Bypass** - This check cannot be disabled or bypassed
5. **Clear Error Message** - Users receive clear guidance on how to enable FDE

**Detection Methods:**
- Check for LUKS devices via `lsblk -o TYPE,FSTYPE`
- Check `/etc/crypttab` for configured encrypted partitions
- Check if root filesystem is on a dm-crypt device
- Check for dm-crypt devices in `/sys/block/dm-*`

**Rationale:**
- An unencrypted build host could be compromised, affecting all built ISOs
- An unencrypted test host exposes the secure OS to attacks during testing
- Supply chain security requires securing the entire build pipeline
- Defense in depth requires protection at every layer

**User Guidance (if FDE not detected):**
1. Backup all data
2. Reinstall with "Guided - use entire disk and set up encrypted LVM"
3. Or use tools like encrypt-existing-debian for in-place encryption

### FR-012: Secure Boot with Unified Kernel Image (UKI) (MANDATORY)

**Priority:** P0 (Critical)
**Status:** Required

**Description:**
The system MUST implement UEFI Secure Boot with a Unified Kernel Image (UKI) to ensure boot integrity and prevent unauthorized code execution during the boot process. This creates a complete chain of trust from firmware to the running operating system.

**Requirements:**
1. **UEFI Boot** - System MUST boot in UEFI mode (no legacy BIOS)
2. **Secure Boot Keys** - Custom PK, KEK, and db keys for signing
3. **Unified Kernel Image** - Kernel, initramfs, and cmdline bundled into single signed EFI binary
4. **Kernel Lockdown** - Kernel must be in lockdown mode when Secure Boot is active
5. **Signature Verification** - All boot components must be cryptographically signed

**Secure Boot Key Hierarchy:**
```
┌─────────────────────────────────────────────────────┐
│                    Trust Chain                       │
├─────────────────────────────────────────────────────┤
│                                                     │
│  UEFI Firmware (Platform Owner)                    │
│       │                                             │
│       ▼                                             │
│  PK (Platform Key) - RSA-4096, SHA-256            │
│       │ Signs KEK updates                          │
│       ▼                                             │
│  KEK (Key Exchange Key) - RSA-4096, SHA-256       │
│       │ Signs db updates                           │
│       ▼                                             │
│  db (Signature Database) - RSA-4096, SHA-256      │
│       │ Signs EFI binaries                         │
│       ▼                                             │
│  UKI (Unified Kernel Image)                        │
│       │ Signed bootloader + kernel + initramfs     │
│       ▼                                             │
│  Operating System                                  │
│                                                     │
└─────────────────────────────────────────────────────┘
```

**UKI Components:**
1. **EFI Stub** - linuxx64.efi.stub for UEFI boot
2. **os-release** - Operating system identification
3. **cmdline** - Kernel command line with security parameters:
   - `lockdown=confidentiality` - Kernel lockdown mode
   - `module.sig_enforce=1` - Require signed kernel modules
4. **linux** - Kernel image (vmlinuz)
5. **initrd** - Initial ramdisk (initramfs)

**Key Specifications:**
- **Algorithm**: RSA-4096
- **Hash**: SHA-256
- **Validity**: 3650 days (10 years)
- **Format**: X.509 certificates, ESL (EFI Signature List)

**Secure Boot Mode:**
- **Setup Mode**: Keys can be enrolled (first boot)
- **User Mode**: Secure Boot active, only signed code boots

**Implementation:**
- Key generation during ISO build
- UKI creation with systemd-boot
- Signature with sbsigntool
- Key storage on ISO for user enrollment

**Security Properties:**
- Bootkit protection - Unauthorized bootloaders cannot execute
- Rootkit protection - Kernel integrity verified at boot
- Module signing enforcement - Only signed kernel modules load
- Chain of trust - Complete verification path from firmware to OS

**Compliance:**
- UEFI Specification 2.3.1+
- NIST SP 800-147 (BIOS Protection)
- NIST SP 800-147B (UEFI Firmware Protection)

---

## Non-Functional Requirements

### NFR-001: Security

**Priority:** P0
**Requirements:**
- Full disk encryption (LUKS2, AES-256-XTS)
- Defense-in-depth architecture
- Zero-trust network model
- Compliance with security frameworks (NIST, ISO 27001)
- No backdoors or secret keys

### NFR-002: Performance

**Priority:** P2
**Requirements:**
- Boot time < 60 seconds (including LUKS passphrase prompt)
- Disk I/O overhead < 5% with encryption
- Memory usage < 2 GB at idle
- CPU usage < 5% at idle

### NFR-003: Reliability

**Priority:** P1
**Requirements:**
- Mean time between failures (MTBF) > 720 hours
- Graceful degradation on errors
- Comprehensive error handling
- Automatic recovery where possible

### NFR-004: Usability

**Priority:** P1
**Requirements:**
- Intuitive installation process
- Clear error messages
- Comprehensive documentation
- Minimal training required

### NFR-005: Maintainability

**Priority:** P1
**Requirements:**
- Clean code structure
- Comprehensive testing
- Well-documented configuration
- Automated build and deployment

### NFR-006: Compliance

**Priority:** P0
**Requirements:**
- NIST SP 800-53 (Security Controls)
- NIST SP 800-111 (Disk Encryption)
- ISO/IEC 27001 (Information Security)
- CIS Benchmarks for Debian Linux
- DISA STIG for Linux

---

## Security Architecture

### Encryption Layer

#### Full Disk Encryption (FDE)
- **Cipher:** AES-256-XTS
- **Key Size:** 512 bits
- **Mode:** LUKS2
- **KDF:** Argon2id (PBKDF2 fallback)
- **Integrity:** dm-integrity layer (optional)

#### Key Management
- Primary: User passphrase (required during boot)
- Recovery: Optional key slot for emergency recovery
- Storage: Keys never stored in plaintext
- Rotation: Key change support via cryptsetup

### Boot Security Layer

#### Secure Boot with UKI
- **Mode:** UEFI Secure Boot (User Mode)
- **Key Hierarchy:** PK → KEK → db → Signed UKI
- **Key Algorithm:** RSA-4096 with SHA-256
- **Validity:** 3650 days (10 years)

#### Chain of Trust
```
UEFI Firmware
     │
     ▼ (verifies PK signature)
PK (Platform Key)
     │
     ▼ (verifies KEK signature)
KEK (Key Exchange Key)
     │
     ▼ (verifies db signature)
db (Signature Database)
     │
     ▼ (verifies UKI signature)
UKI (Unified Kernel Image)
     │
     ▼
Linux Kernel (lockdown mode)
```

#### Kernel Lockdown
- **Mode:** confidentiality (strict)
- **Module Signing:** Enforced (module.sig_enforce=1)
- **Effect:** Prevents kernel module loading without valid signature
- **Effect:** Prevents /dev/mem and /dev/kmem access
- **Effect:** Blocks kexec and hibernation to untrusted storage

### Network Security Layer

#### VPN-Only Access
- **Protocol:** WireGuard
- **Encryption:** ChaCha20-Poly1305
- **Authentication:** Public/private key pairs
- **Configuration:** Dynamic endpoint-based firewall rules

#### Firewall Rules
```
Default Policy: DROP ALL

Inbound Rules:
- NONE (all inbound traffic denied)
- Established/related connections allowed (for return traffic only)

Outbound Rules:
- WireGuard VPN traffic to endpoints only
- DNS through VPN tunnel only
- ALL traffic through VPN interface only
```

### System Security Layer

#### Kernel Hardening
- Module blacklisting (WiFi, Bluetooth)
- Secure kernel parameters
- Restricted ptrace scope
- Kernel address space layout randomization (KASLR)

#### Process Security
- Resource limits (ulimits)
- Service hardening (systemd sandboxing)
- Mandatory access control (optional SELinux/AppArmor)

### Access Control Layer

#### Authentication
- **Password Policy:** 14+ characters, complexity required
- **SSH:** Client-only, key-based authentication for outbound connections
- **Sudo:** Limited sudo access for authorized users

#### Authorization
- **User Groups:** Minimal necessary groups only
- **File Permissions:** Secure default permissions
- **Sudo Configuration:** Specific command permissions
- **Audit Logging:** Track all privilege usage

---

## Data Requirements

### DR-001: Data at Rest

**Priority:** P0
**Requirements:**
- All system data encrypted at rest (LUKS2)
- Encryption key protected by user passphrase
- No plaintext data storage
- Secure deletion of temporary files

### DR-002: Data in Transit

**Priority:** P0
**Requirements:**
- All network traffic encrypted via VPN
- SSH encryption for remote access
- TLS for any HTTPS traffic (if applicable)
- No plaintext protocols allowed

### DR-003: Data Retention

**Priority:** P2
**Requirements:**
- Log retention: 90 days minimum
- User data: User-controlled
- System data: Until reinstallation
- Secure wipe on decommission

---

## User Requirements

### UR-001: Target Users

1. **Tier0 Infrastructure Engineers** - Primary users
2. **System Administrators** - Secondary users
3. **Security Auditors** - Compliance verification users

### UR-002: User Scenarios

**Scenario 1: Initial System Installation**
1. Boot ISO on target hardware
2. Configure disk encryption passphrase
3. Complete automated installation
4. Reboot into encrypted system
5. Configure WireGuard VPN

**Scenario 2: Daily System Use**
1. System prompts for encryption passphrase at boot
2. User logs in (username/password)
3. VPN automatically connects
4. User accesses infrastructure via SSH/Remmina

**Scenario 3: USB Data Transfer**
1. User inserts USB device
2. System automatically mounts to /media/username/device
3. User copies files to/from USB
4. User safely removes USB device

**Scenario 4: VPN Configuration**
1. User scans QR code with camera
2. System imports WireGuard configuration
3. Firewall rules updated automatically
4. VPN connection established

### UR-003: User Interface Requirements

**Login Screen:**
- Display system name only
- No user list (privacy mode)
- Require username entry
- Require password entry
- No guest account option

**Desktop Environment:**
- Minimal interface (IceWM)
- Application launcher
- System tray (VPN status indicator)
- Terminal access
- No unnecessary widgets

---

## Technical Requirements

### TR-001: System Requirements

**Minimum Hardware:**
- CPU: x86_64 (AMD64), 2 cores
- RAM: 4 GB (8 GB recommended)
- Storage: 64 GB SSD (128 GB recommended)
- Network: Ethernet (1 Gbps recommended)
- UEFI: UEFI 2.3+ firmware

**Recommended Hardware:**
- CPU: x86_64 (AMD64), 4+ cores
- RAM: 8 GB
- Storage: 256 GB NVMe SSD
- Network: Ethernet 10 Gbps
- UEFI: UEFI 2.7+ with Secure Boot

**Unsupported Hardware:**
- 32-bit systems (x86, ARM32)
- Legacy BIOS systems
- Systems without UEFI firmware
- Systems with < 4 GB RAM
- Systems with < 64 GB storage

### TR-002: Software Requirements

**Included Software:**
- Debian 13 base system
- Linux kernel (latest stable)
- IceWM window manager
- LightDM display manager
- WireGuard and tools
- OpenSSH client
- nftables firewall
- Remmina (remote desktop)
- Mousepad (text editor)
- zbar-tools (QR code scanning)

**Excluded Software:**
- Package managers (apt/dpkg for users)
- Wireless drivers and tools
- Bluetooth stack
- Printing system (CUPS)
- Cloud storage clients
- Media players
- Web browsers

### TR-003: Encryption Requirements

**LUKS2 Configuration:**
- Cipher: aes-xts-plain64
- Key size: 512 bits (256-bit keys for XTS)
- Hash: SHA-512
- KDF: Argon2id (with appropriate iterations)
- Salt size: 512 bits
- Key slots: 8 maximum (default: 1 used)

**Partition Layout (UEFI):**
```
/dev/sda1    512M    EFI System Partition (FAT32)
/dev/sda2    512M    /boot (ext4, unencrypted)
/dev/sda3    Remainder    LUKS2 encrypted container
  └─ cryptroot (mapped device)    / (ext4)
```

**Boot Process:**
1. UEFI firmware loads GRUB from EFI System Partition
2. GRUB loads kernel and initramfs from /boot
3. initramfs prompts for encryption passphrase
4. LUKS container unlocked with passphrase
5. Root filesystem mounted
6. System boots normally

---

## Compliance Requirements

### CR-001: Regulatory Compliance

**NIST SP 800-53 (Security and Privacy Controls)**
- AC-2: Account Management
- AC-3: Access Enforcement
- AC-6: Least Privilege
- AU-2: Audit Events
- AU-3: Content of Audit Records
- AU-6: Audit Review, Analysis, and Reporting
- CM-3: Configuration Change Control
- CM-7: Least Functionality
- CM-8: System Components Inventory
- CP-7: Alternate Storage Site
- CP-9: System Backup
- CP-10: Information System Recovery and Reconstitution
- IA-2: Identification and Authentication
- IA-5: Authenticator Management
- SC-8: Transmission Confidentiality and Integrity
- SC-12: Cryptographic Key Establishment and Management
- SC-13: Cryptographic Protection
- SC-28: Protection of Information at Rest

**NIST SP 800-111 (Guide to Storage Encryption)**
- Full disk encryption implementation
- Cryptographic algorithm selection
- Key management procedures
- Authentication requirements

**ISO/IEC 27001:2013 (Information Security)**
- A.9 Access Control
- A.10 Cryptography
- A.12 Operations Security
- A.14 System Acquisition, Development, and Maintenance

**CIS Benchmarks for Debian Linux**
- Initial setup guidelines
- Logging and monitoring
- Network configuration
- System access, authentication, and authorization

**DISA STIG for Linux**
- Firewall configuration
- System services configuration
- File permissions and ownership

### CR-002: Security Compliance

**Encryption Standards:**
- FIPS 140-2 Level 1 (certified algorithms)
- FIPS 197 (AES encryption)
- FIPS 180-4 (SHA hash functions)
- FIPS 202 (SHA-3 hash functions)

**Cryptographic Protocols:**
- TLS 1.3 (for any HTTPS)
- WireGuard protocol (VPN)
- SSH-2 protocol

**Key Management:**
- Secure key generation (CSPRNG)
- Secure key storage
- Key rotation support
- Secure key destruction

---

## Testing Requirements

### TST-001: Unit Testing

**Coverage:**
- All security hardening scripts
- Configuration generation scripts
- Key management functions
- Firewall rule generation

**Test Cases:**
- WiFi/Bluetooth module blacklisting verification
- SSH configuration validation
- Firewall rule validation
- Password policy enforcement

### TST-002: Integration Testing

**Test Scenarios:**
- Complete ISO build process
- Installation in virtual machine
- Encryption setup and verification
- VPN configuration and connectivity
- USB device handling

### TST-003: Security Testing

**Test Areas:**
- Full disk encryption verification
- Network isolation testing
- Firewall rule validation
- Authentication mechanism testing
- Privilege escalation prevention

### TST-004: Compliance Testing

**Validation:**
- NIST SP 800-53 control coverage
- NIST SP 800-111 encryption guidelines
- CIS Benchmark compliance
- Security configuration validation

### TST-005: Performance Testing

**Metrics:**
- Boot time with encryption
- Disk I/O performance impact
- Memory usage at idle
- Network throughput over VPN

---

## Quality Assurance

### QA-001: Code Quality

**Standards:**
- Shell scripts: Shellcheck compliant
- Configuration: Follow Debian conventions
- Documentation: Clear and complete
- Version control: Git with meaningful commits

### QA-002: Build Quality

**Requirements:**
- Reproducible builds
- Clean build logs
- No build warnings
- Automated checksum verification

### QA-003: Release Quality

**Criteria:**
- All tests passing
- Security scan clean
- Documentation complete
- Signed release artifacts

---

## Documentation Requirements

### DOC-001: User Documentation

**Required Documents:**
1. User Manual (installation and daily use)
2. Troubleshooting Guide
3. Security Configuration Guide
4. VPN Configuration Guide

### DOC-002: Technical Documentation

**Required Documents:**
1. System Architecture Documentation
2. Security Model Documentation
3. Build Process Documentation
4. API/Configuration Documentation

### DOC-003: Developer Documentation

**Required Documents:**
1. Contributor Guidelines
2. Code Style Guide
3. Testing Guidelines
4. Release Process Documentation

### DOC-004: Compliance Documentation

**Required Documents:**
1. Security Control Implementation Guide
2. Compliance Matrix (NIST, ISO, CIS)
3. Risk Assessment Report
4. Penetration Test Reports

---

## Deployment Requirements

### DEP-001: Distribution

**Distribution Methods:**
- ISO image download (official website)
- Secure distribution (HTTPS, verified checksums)
- GPG signature verification
- Release announcement channels

### DEP-002: Installation

**Installation Methods:**
- USB bootable media (recommended)
- Virtual machine deployment (testing)
- Automated installation (preseed configuration)
- Manual installation (expert mode)

**Installation Requirements:**
- UEFI firmware (mandatory)
- 64-bit AMD64 architecture
- Minimum 64 GB storage
- Minimum 4 GB RAM
- Ethernet network interface

### DEP-003: Updates

**Update Strategy:**
- Major updates: New ISO release
- Security patches: New ISO release
- Configuration changes: New ISO release
- No in-place system updates

**Update Frequency:**
- Major releases: Quarterly
- Security releases: As needed
- Emergency releases: Critical vulnerabilities only

---

## Risk Management

### RISK-001: Security Risks

**High Priority Risks:**
1. **Encryption Bypass** - Attackers attempt to bypass encryption
   - Mitigation: LUKS2, strong passphrase, secure key management

2. **Physical Access** - Attackers gain physical access to hardware
   - Mitigation: Full disk encryption, secure boot, TPM (optional)

3. **VPN Compromise** - VPN endpoint or configuration compromised
   - Mitigation: Key rotation, endpoint hardening, audit logging

**Medium Priority Risks:**
4. **USB Attacks** - Malicious USB devices inserted
   - Mitigation: Restricted mounting, no auto-execution, audit logging

5. **Privilege Escalation** - Users attempt to gain root access
   - Mitigation: Strong passwords, sudo restrictions, audit logging

6. **Configuration Drift** - System configuration modified
   - Mitigation: Immutable attributes, audit logging, compliance checks

### RISK-002: Operational Risks

**Risks:**
- Lost encryption passphrase (data loss)
- System corruption (reinstallation required)
- Hardware failure (recovery procedures needed)
- User error (documentation and training)

**Mitigations:**
- Backup key slot recommendation
- Comprehensive recovery documentation
- Regular system backups (if applicable)
- Clear user documentation

---

## Success Criteria

### SC-001: Technical Success

- Full disk encryption implemented and functional (MANDATORY)
- ISO builds successfully (reproducible)
- All tests passing (100% pass rate)
- Security controls implemented (100% coverage)

### SC-002: Security Success

- Full disk encryption verified (LUKS2, AES-256-XTS)
- Compliance achieved (NIST, ISO, CIS)
- Security assessment passed (critical vulnerabilities = 0)
- Penetration test passed (high-severity issues = 0)

### SC-003: Operational Success

- System boots within 60 seconds (with passphrase prompt)
- Disk I/O overhead < 5% with encryption
- User can complete common tasks without issues
- Documentation is comprehensive and accurate

---

## Future Enhancements

### FE-001: Potential Enhancements

1. **TPM Integration** - Use TPM for passphrase storage (optional)
2. **Smart Card Support** - Smart card-based authentication
3. **Hardware Security Module (HSM)** - Enterprise key management
4. **Trusted Platform Module (TPM)** - Boot attestation
5. **Secure Boot** - Full secure boot chain verification
6. **SELinux/AppArmor** - Mandatory access control
7. **Multi-User Support** - Multiple user accounts (future consideration)
8. **Automated Backup** - Encrypted backup solution
9. **Remote Wipe** - Secure data destruction capability
10. **Hardware Inventory** - Automatic hardware inventory tracking

### FE-002: Research Areas

1. **Alternative Encryption** - Evaluate dm-crypt with dm-integrity
2. **Post-Quantum Cryptography** - Quantum-resistant algorithms
3. **Hardware Enclaves** - Intel SGX or AMD SEV
4. **Containerization** - Application-level isolation
5. **Zero Trust Networking** - Enhanced zero-trust model

---

## Appendix A: Terminology

| Term | Definition |
|------|------------|
| FDE | Full Disk Encryption - Encryption of entire storage device |
| LUKS | Linux Unified Key Setup - Disk encryption specification |
| LUKS2 | Second version of LUKS with enhanced features |
| AES-XTS | Advanced Encryption Standard in XEX-based Tweaked CodeBook mode |
| KDF | Key Derivation Function - Derives encryption keys from password |
| UEFI | Unified Extensible Firmware Interface - Modern firmware interface |
| ESP | EFI System Partition - FAT32 partition for UEFI boot files |
| VPN | Virtual Private Network - Encrypted network tunnel |
| WireGuard | Modern, high-performance VPN protocol |
| nftables | Linux packet filtering framework |
| IceWM | Ice Window Manager - Lightweight window manager |
| LightDM | Light Display Manager - Cross-desktop display manager |

---

## Appendix B: References

1. NIST SP 800-53: Security and Privacy Controls for Information Systems
2. NIST SP 800-111: Guide to Storage Encryption Technologies for End User Devices
3. ISO/IEC 27001:2013: Information Security Management Systems
4. CIS Benchmarks: Center for Internet Security Security Configuration Guides
5. DISA STIG: Defense Information Systems Agency Security Technical Implementation Guides
6. LUKS Specification: https://gitlab.com/cryptsetup/LUKS2-docs
7. WireGuard Protocol: https://www.wireguard.com/protocol/
8. Debian Live Manual: https://live-team.pages.debian.net/live-manual/

---

## Appendix C: Change History

| Version | Date | Author | Changes |
|---------|------|--------|---------|
| 1.0 | 2026-01-28 | KNEL-Football Team | Initial PRD with mandatory full disk encryption |

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**Copyright © 2026 Known Element Enterprises LLC**
**License: GNU Affero General Public License v3.0 only**

This PRD is maintained as part of the KNEL-Football project and is updated when requirements change or new features are added.