Zero Trust Security Complete Guide 2026

Zero Trust Principles:
├── Never trust, always verify
│   └── Every access request authenticated
│
├── Assume breach
│   └── Design for lateral movement prevention
│
├── Verify explicitly
│   └── All data sources and connections
│
├── Least privilege access
│   └── Minimize user access
│
└── Continuous monitoring
    └── Real-time threat detection

MFA Methods:
├── Something you know
│   ├── Password
│   └── PIN
│
├── Something you have
│   ├── Hardware token (YubiKey)
│   ├── Authenticator app (TOTP)
│   └── SMS (less secure)
│
└── Something you are
    ├── Fingerprint
    ├── Face recognition
    └── Voice recognition

# OAuth 2.0 / OIDC flow
class IdentityProvider:
    def __init__(self, client_id, client_secret, redirect_uri):
        self.client_id = client_id
        self.client_secret = client_secret
        self.redirect_uri = redirect_uri
    
    def authorize_url(self, state):
        """Generate authorization URL"""
        params = {
            'client_id': self.client_id,
            'redirect_uri': self.redirect_uri,
            'response_type': 'code',
            'scope': 'openid profile email',
            'state': state
        }
        return f"https://auth.example.com/authorize?{urlencode(params)}"
    
    def exchange_code(self, code):
        """Exchange authorization code for tokens"""
        response = requests.post(
            "https://auth.example.com/token",
            data={
                'grant_type': 'authorization_code',
                'code': code,
                'client_id': self.client_id,
                'client_secret': self.client_secret
            }
        )
        return response.json()

Micro-Segmentation Strategy:
├── Identify workloads
│   ├── Web tier
│   ├── Application tier
│   ├── Database tier
│   └── Admin tools
│
├── Define policies
│   ├── Allow: Web → App
│   ├── Allow: App → Database
│   ├── Deny: Web → Database
│   └── Allow: Admin → All (with MFA)
│
└── Implement controls
    ├── Network policies (Kubernetes)
    ├── Security groups (AWS/Azure)
    └── Firewall rules

Endpoint Security Components:
├── Mobile Device Management (MDM)
│   ├── Device inventory
│   ├── Policy enforcement
│   └── Remote wipe
│
├── Endpoint Detection and Response (EDR)
│   ├── Real-time monitoring
│   ├── Threat detection
│   └── Incident response
│
└── Network Access Control (NAC)
    ├── Device classification
    ├── Access control
    └── Quarantine

# Zero trust logging
class ZeroTrustLogger:
    def __init__(self, siem_client):
        self.siem = siem_client
    
    def log_access(self, event):
        """Log all access events"""
        log_entry = {
            'timestamp': datetime.utcnow().isoformat(),
            'event_type': 'access_attempt',
            'user': event.user,
            'resource': event.resource,
            'action': event.action,
            'result': event.result,
            'device': event.device_id,
            'ip': event.source_ip,
            'risk_score': self.calculate_risk(event)
        }
        self.siem.send(log_entry)
    
    def calculate_risk(self, event):
        """Calculate risk score"""
        score = 0
        
        if event.unusual_location:
            score += 30
        if event.new_device:
            score += 20
        if event.after_hours:
            score += 10
        
        return min(score, 100)