# I Created a JWT Auth Challenge… And AI Failed to Catch the Biggest Security Flaw 🔐

JWT authentication is everywhere.

Most apps use it.

And at first glance, it looks simple.

Encode user data → send token → verify → done.

But is it really that simple?

So I created a small challenge on VibeCode Arena to test this.

🚨 The Problem

The implementation looked like it worked.

• Token is generated
• Token is decoded
• Role is checked

Everything seems fine.

But there’s a serious issue.

The token is not signed.

Which means…

👉 Anyone can modify it.

🧠 What I Observed

When AI models tried this challenge:

• Some just decoded the token
• Some ignored tampering risks
• Some didn’t add expiration
• Very few treated it as a security problem

The code works.

But the system is completely unsafe.

🔥 Try It Yourself

I created this challenge to test real-world authentication thinking.

👉 Try it here:
https://vibecodearena.ai/share/5fa943aa-2697-4227-b6b3-edfdbd57ff29

Can you:

• Prevent token tampering?
• Add proper expiration?
• Design secure authentication flow?

💡 Final Thought

JWT is not just encoding data.

It’s about trust and verification.

If you don’t secure it properly…

You’re not authenticating users.

You’re trusting anyone.

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Would you trust AI with authentication logic?

Let’s discuss 👇