# Zero Trust Architecture Implementation

## Overview

The ETB-API security module now implements a comprehensive Zero Trust Architecture that goes beyond traditional perimeter-based security. This implementation provides context-aware, risk-based access control that continuously verifies and validates every access request.

## Core Zero Trust Principles

### 1. **Never Trust, Always Verify**
- Every access request is evaluated regardless of source
- Continuous verification of user identity and device trust
- No implicit trust based on network location

### 2. **Least Privilege Access**
- Users receive minimum necessary access based on context
- Dynamic permission adjustment based on risk assessment
- Time-limited access with automatic expiration

### 3. **Assume Breach**
- Continuous monitoring and threat detection
- Behavioral anomaly detection
- Rapid response to security incidents

## Zero Trust Components

### 1. Device Posture Assessment

**Purpose**: Evaluate the security posture of devices attempting to access the system.

**Features**:
- Device identification and fingerprinting
- Security configuration assessment (antivirus, firewall, encryption)
- Network type detection (corporate, home, public)
- VPN connection status
- Compliance verification
- Risk scoring (0-100)

**API Endpoints**:
```http
GET /security/api/device-postures/          # List user's devices
POST /security/api/device-postures/         # Register new device
POST /security/api/device-postures/{id}/update_posture/  # Update device info
POST /security/api/device-postures/register_device/      # Register device
```

**Example Device Registration**:
```json
{
  "device_id": "unique-device-identifier",
  "device_name": "John's Laptop",
  "device_type": "LAPTOP",
  "os_type": "WINDOWS",
  "os_version": "Windows 11",
  "is_managed": true,
  "has_antivirus": true,
  "firewall_enabled": true,
  "encryption_enabled": true,
  "screen_lock_enabled": true,
  "biometric_auth": true,
  "network_type": "Corporate",
  "vpn_connected": true
}
```

### 2. Geolocation-Based Access Control

**Purpose**: Control access based on geographic location and network context.

**Features**:
- Country, region, and city-based restrictions
- IP range allow/block lists
- Distance-based access control from office locations
- Time zone and working hours restrictions
- Risk-based location scoring

**API Endpoints**:
```http
GET /security/api/geolocation-rules/        # List geolocation rules
POST /security/api/geolocation-rules/       # Create new rule
POST /security/api/geolocation-rules/{id}/test_rule/  # Test rule
```

**Example Geolocation Rule**:
```json
{
  "name": "Bulgaria Office Access",
  "rule_type": "ALLOW",
  "allowed_countries": ["BG"],
  "allowed_cities": ["Sofia", "Plovdiv", "Varna"],
  "max_distance_from_office": 50.0,
  "office_latitude": 42.6977,
  "office_longitude": 23.3219,
  "working_hours_only": true,
  "working_hours_start": "08:00",
  "working_hours_end": "18:00",
  "working_days": [0, 1, 2, 3, 4]
}
```

### 3. Risk Assessment Engine

**Purpose**: Continuously assess risk for every access request using multiple factors.

**Risk Factors**:
- **Device Risk** (25%): Device security posture and compliance
- **Location Risk** (20%): Geographic and network location
- **Behavior Risk** (20%): User behavior patterns and anomalies
- **Network Risk** (15%): Network security and VPN status
- **Time Risk** (10%): Access time and working hours
- **User Risk** (10%): User account status and history

**Risk Levels**:
- **LOW** (0-25): Normal access granted
- **MEDIUM** (26-50): Step-up authentication required
- **HIGH** (51-75): Manual review required
- **CRITICAL** (76-100): Access denied

**API Endpoints**:
```http
GET /security/api/risk-assessments/         # List user's assessments
POST /security/api/risk-assessments/assess_access/  # Perform assessment
GET /security/api/risk-assessments/my_risk_profile/  # Get risk profile
```

### 4. Adaptive Authentication

**Purpose**: Dynamically adjust authentication requirements based on risk level.

**Features**:
- Risk-based authentication method selection
- Context-aware risk adjustment
- Behavioral analysis integration
- Machine learning support (optional)
- Fallback authentication methods

**Authentication Methods**:
- Password
- MFA TOTP
- MFA SMS/Email
- Biometric
- Hardware Token
- SSO
- Certificate

**API Endpoints**:
```http
GET /security/api/adaptive-auth/            # List adaptive auth configs
POST /security/api/adaptive-auth/{id}/test_auth_requirements/  # Test requirements
```

### 5. Behavioral Analysis

**Purpose**: Learn and detect anomalous user behavior patterns.

**Features**:
- Login time and location patterns
- Device usage patterns
- Access frequency analysis
- Session duration tracking
- Anomaly scoring (0-1)

**API Endpoints**:
```http
GET /security/api/behavior-profiles/        # List behavior profiles
POST /security/api/behavior-profiles/{id}/calculate_anomaly/  # Calculate anomaly
```

## Zero Trust Middleware

The system includes three middleware components that automatically apply Zero Trust principles:

### 1. ZeroTrustMiddleware
- Intercepts all requests
- Performs risk assessment
- Applies access policies
- Updates behavior profiles

### 2. DeviceRegistrationMiddleware
- Handles device registration requests
- Validates device information
- Creates device posture records

### 3. RiskBasedRateLimitMiddleware
- Applies rate limiting based on risk level
- Higher risk = stricter limits
- Prevents abuse and brute force attacks

## Configuration

### Settings Configuration

```python
# Zero Trust Architecture Settings
ZERO_TRUST_ENABLED = True
ZERO_TRUST_STRICT_MODE = False  # Set to True for maximum security

# Geolocation API Settings
GEO_API_KEY = "your-api-key"  # Set your geolocation API key
GEO_API_PROVIDER = 'ipapi'  # Options: 'ipapi', 'ipinfo', 'maxmind'

# Device Posture Assessment
DEVICE_POSTURE_ENABLED = True
DEVICE_POSTURE_STRICT_MODE = False
DEVICE_POSTURE_UPDATE_INTERVAL = 3600  # Update every hour

# Risk Assessment Settings
RISK_ASSESSMENT_ENABLED = True
RISK_ASSESSMENT_CACHE_TTL = 300  # Cache for 5 minutes
RISK_ASSESSMENT_ML_ENABLED = False  # Enable ML-based assessment

# Behavioral Analysis Settings
BEHAVIORAL_ANALYSIS_ENABLED = True
BEHAVIORAL_LEARNING_PERIOD = 30  # Days to learn behavior
BEHAVIORAL_ANOMALY_THRESHOLD = 0.7  # Anomaly threshold

# Adaptive Authentication Settings
ADAPTIVE_AUTH_ENABLED = True
ADAPTIVE_AUTH_FALLBACK_METHODS = ['PASSWORD', 'MFA_TOTP']
ADAPTIVE_AUTH_MAX_ATTEMPTS = 3
ADAPTIVE_AUTH_LOCKOUT_DURATION = 15  # minutes
```

## API Usage Examples

### 1. Check Zero Trust Status

```bash
curl -X GET "http://localhost:8000/security/api/zero-trust/status/" \
  -H "Authorization: Token your-token"
```

**Response**:
```json
{
  "zero_trust_enabled": true,
  "user_status": {
    "registered_devices": 2,
    "trusted_devices": 1,
    "latest_risk_level": "MEDIUM",
    "latest_risk_score": 35
  },
  "system_configuration": {
    "adaptive_auth_enabled": true,
    "geolocation_rules_count": 3,
    "behavioral_analysis_enabled": true,
    "device_posture_enabled": true
  },
  "recommendations": [
    {
      "type": "device",
      "priority": "medium",
      "message": "1 untrusted devices detected",
      "action": "improve_device_security"
    }
  ]
}
```

### 2. Perform Risk Assessment

```bash
curl -X POST "http://localhost:8000/security/api/zero-trust/assess/" \
  -H "Authorization: Token your-token" \
  -H "Content-Type: application/json" \
  -d '{
    "assessment_type": "ACCESS",
    "resource_type": "incident",
    "device_id": "device-123",
    "location_data": {
      "latitude": 42.6977,
      "longitude": 23.3219,
      "country_code": "BG",
      "city": "Sofia"
    }
  }'
```

**Response**:
```json
{
  "access_granted": true,
  "reason": "Access granted - low risk",
  "required_actions": [],
  "risk_level": "LOW",
  "risk_score": 25,
  "auth_requirements": ["PASSWORD"],
  "assessment_id": "uuid-here"
}
```

### 3. Register Device

```bash
curl -X POST "http://localhost:8000/security/api/device-postures/register_device/" \
  -H "Authorization: Token your-token" \
  -H "Content-Type: application/json" \
  -d '{
    "device_id": "unique-device-id",
    "device_name": "My Laptop",
    "device_type": "LAPTOP",
    "os_type": "WINDOWS",
    "is_managed": true,
    "has_antivirus": true,
    "firewall_enabled": true,
    "encryption_enabled": true
  }'
```

## Security Benefits

### 1. **Enhanced Security Posture**
- Continuous verification of all access requests
- Context-aware access decisions
- Reduced attack surface through least privilege

### 2. **Improved Compliance**
- Comprehensive audit trails
- Risk-based access controls
- Regulatory compliance support (GDPR, ISO 27001, SOC 2)

### 3. **Better User Experience**
- Adaptive authentication reduces friction for low-risk access
- Transparent security controls
- Self-service device registration

### 4. **Operational Efficiency**
- Automated risk assessment
- Reduced manual security reviews
- Proactive threat detection

## Implementation Considerations

### 1. **Performance**
- Risk assessments are cached for 5 minutes
- Geolocation lookups are optimized
- Database queries are indexed for performance

### 2. **Scalability**
- Middleware can be disabled for high-traffic scenarios
- Risk assessment can be moved to background tasks
- Caching strategies for large-scale deployments

### 3. **Privacy**
- User behavior data is anonymized
- Geolocation data is not stored permanently
- Compliance with data protection regulations

### 4. **Monitoring**
- Comprehensive audit logging
- Risk assessment metrics
- Security event correlation

## Future Enhancements

### 1. **Machine Learning Integration**
- ML-based risk scoring
- Behavioral pattern recognition
- Predictive threat detection

### 2. **Advanced Analytics**
- Risk trend analysis
- Security posture dashboards
- Compliance reporting

### 3. **Integration Capabilities**
- SIEM integration
- Threat intelligence feeds
- External security tools

## Conclusion

The Zero Trust Architecture implementation provides a robust, scalable, and comprehensive security framework that continuously adapts to changing threat landscapes while maintaining usability and compliance requirements. This implementation positions the ETB-API as a leader in enterprise security architecture.