Zero trust network architecture in Computer Networks - Step-by-Step Execution

Concept Flow - Zero trust network architecture

User or Device Requests Access

↓

Verify Identity and Device Health

↓

Check Access Policies

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Grant Least Privilege Access

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Monitor and Log Activity

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Re-evaluate Continuously

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Access Ends

This flow shows how zero trust verifies every access request by checking identity, device health, and policies before granting limited access, then continuously monitors activity.

Execution Sample

Computer Networks

User requests access
Verify user identity
Check device security
Apply access policy
Grant limited access
Monitor session continuously

This sequence shows the step-by-step process of how zero trust handles an access request.

Analysis Table

Step	Action	Check/Decision	Result/Output
1	User requests access	N/A	Access request received
2	Verify user identity	Is user authenticated?	Yes - proceed; No - deny access
3	Check device security	Is device compliant?	Yes - proceed; No - deny or limit access
4	Apply access policy	What permissions are allowed?	Grant least privilege access
5	Monitor session continuously	Is any suspicious activity detected?	If yes, revoke or limit access; else continue
6	Re-evaluate access	Is session still valid?	If no, end access; else continue monitoring

💡 Access ends when user logs out or session is revoked due to policy or suspicious activity

State Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 5	Final
User Identity	Unknown	Verified	Verified	Verified	Verified	Verified
Device Status	Unknown	Unknown	Compliant	Compliant	Compliant	Compliant
Access Level	None	None	None	Least Privilege	Least Privilege	Least Privilege
Session State	Inactive	Inactive	Inactive	Active	Active	Ended or Active

Key Insights - 3 Insights

Why does zero trust verify identity every time instead of trusting once?

Because zero trust assumes no user or device is inherently trusted, it verifies identity at each access attempt to prevent unauthorized access, as shown in steps 2 and 6 of the execution_table.

What does 'least privilege access' mean in zero trust?

It means granting only the minimum access rights needed for the task, reducing risk if credentials are compromised, as seen in step 4 where access policy limits permissions.

Why is continuous monitoring important in zero trust?

Because threats can arise anytime during a session, continuous monitoring (step 5) helps detect suspicious activity and revoke access promptly to protect resources.

Visual Quiz - 3 Questions

Look at the execution_table, what is the result after verifying user identity at step 2?

A Access request denied

B Yes - proceed; No - deny access

C Device compliance checked

D Session ended

💡 Hint

Check the 'Result/Output' column for step 2 in the execution_table

At which step does zero trust apply the principle of least privilege?

A Step 4 - Apply access policy

B Step 3 - Check device security

C Step 5 - Monitor session

D Step 6 - Re-evaluate access

💡 Hint

Look for where access permissions are granted in the execution_table

If the device is not compliant at step 3, what happens according to the execution_table?

A Access is granted fully

B User identity is re-verified

C Access is denied or limited

D Session monitoring starts

💡 Hint

Check the 'Check/Decision' and 'Result/Output' columns for step 3

Concept Snapshot

Zero trust network architecture means never trusting any user or device by default.
Every access request is verified for identity and device health.
Access is granted with least privilege needed.
Continuous monitoring detects threats during sessions.
Access is re-evaluated and revoked if suspicious activity occurs.

Full Transcript

Zero trust network architecture is a security approach where no user or device is trusted by default. Every access request goes through verification steps: first, the user's identity is checked to confirm they are who they say they are. Then, the device's security status is checked to ensure it meets compliance rules. Based on these checks, access policies are applied to grant only the minimum permissions needed, called least privilege. During the session, continuous monitoring watches for any suspicious activity. If any threat is detected or the session becomes invalid, access is revoked immediately. This approach helps protect resources by assuming breach and verifying every action.