BB84 Quantum Key Distribution Simulator

"Where quantum physics meets unbreakable encryption"

A hands-on journey through quantum cryptography - Experience the revolutionary BB84 protocol that uses the strange laws of quantum mechanics to create perfectly secure communication.

Why This Matters

In a world of increasing cyber threats, quantum cryptography offers:

• Provable security backed by physics laws
• Eavesdropper detection - know immediately if someone's listening
• Future-proof protection against quantum computers

This simulator makes these complex concepts visually intuitive and interactive.

How to Use

1. Alice prepares qubits in random states (|0⟩, |1⟩, |+⟩, |-⟩)
2. Bob measures them in random bases
3. Compare bases to distill a secret key
4. Toggle Eve to see how quantum mechanics exposes eavesdroppers

Run locally

git clone https://github.com/Luciferjimmy/BB84-Quantum-Key-Distribution-QKD-simulator.git cd BB84-Quantum-Key-Distribution-QKD-simulator python bb84_simulation.py

Key Features

Feature Description Realistic Qubit Visualization See photons in different polarization states Interactive Eve Watch how eavesdropping introduces detectable errors Error Rate Calculation Automatic QBER (Quantum Bit Error Rate) analysis

Simulation Output Example

Output- 🔁 Attempt 3 Sifted Key Length: 9 QBER: 22.22% Eve Detected: True Sifted Key (Alice): [1, 0, 1, 1, 0, 0, 1, 0, 1] Sifted Key (Bob): [1, 0, 0, 1, 1, 0, 1, 0, 1]

✅ Secure key established after 3 attempts!

The Science Behind It

The BB84 protocol leverages two quantum principles:

• Heisenberg Uncertainty Principle: Measuring quantum states disturbs them
• No-Cloning Theorem: Quantum states cannot be perfectly copied

When Eve intercepts:

• She guesses wrong basis 75% of the time
• Introduces ~25% error rate (detectable by Alice & Bob)
• Perfect security when QBER < 11%

Dependencies

Python 3.8+ Qiskit Matplotlib NumPy

Roadmap

• Add quantum channel noise simulation
• Implement error correction
• Add multi-qubit entanglement visualization

How to Contribute

We welcome quantum enthusiasts! To contribute:

• Fork the repository
• Create a feature branch (git checkout -b feature/quantum-magic)
• Commit your changes (git commit -m 'Add Schrödinger mode')
• Push to the branch (git push origin feature/quantum-magic)
• Open a Pull Request

License

MIT License - See LICENSE for details.

The quantum security revolution starts here. Clone the repo and experience the future of encryption today!

"The universe is not only stranger than we imagine, it's stranger than we can imagine." - J.B.S. Haldane