What is Zero Trust?
Zero Trust is a modern cybersecurity model that operates on the principle:
“Never trust, always verify.”
It assumes that no user, device, or system—whether inside or outside the network—should be trusted by default. Every access request must be continuously authenticated, authorized, and validated based on user identity, device health, location, behavior, and other risk signals.
What is Implicit Trust?
Implicit Trust is the foundational flaw in traditional perimeter-based security models. Under this approach:
- The network perimeter (firewalls, VPNs) was seen as the primary barrier.
- Once inside that perimeter, users and devices were assumed to be safe.
- Internal traffic was largely unmonitored and unrestricted.
This model is like locking your front door, but leaving every room inside your house open and trusting anyone who walks through the door.
Key Differences
| Feature/Concept |
Implicit Trust (Perimeter Defense) |
Zero Trust Architecture |
| Trust Model |
Trust by default if inside the network |
No trust by default—verify every access attempt |
| Network Boundary |
Strong perimeter, weak internal segmentation |
No perimeter—trust boundaries are everywhere |
| Authentication |
One-time at login or network entry |
Continuous, context-based verification |
| Access Control |
Broad lateral access inside the network |
Least privilege, granular access to specific assets |
| User/Device Behavior |
Not continuously monitored |
Continuously evaluated for anomalies |
Real-World Example:
Scenario: An Employee’s Laptop is Compromised
- Implicit Trust Model (Perimeter Defense):
- The employee connects to the corporate VPN from a compromised device.
- Once authenticated, they have wide access across internal systems—files, email, apps.
- The attacker uses lateral movement to reach critical servers and deploy ransomware.
- Zero Trust Model:
- The device is flagged as risky based on unusual behavior and fails posture checks.
- Even if login credentials are correct, access is blocked or limited.
- The user must pass multi-factor authentication and device health checks.
- Access is segmented: they can only reach what’s needed for their role.
- Any abnormal activity triggers real-time monitoring and alerts.
Everyday Analogy
- Implicit Trust: Like giving someone access to an entire office building because they showed a valid ID at the front desk.
- Zero Trust: Like requiring a separate keycard, fingerprint scan, and security check at every door, based on who the person is and whether they should be in that room.
Summary