Quantum Password Cracking with Grover's Algorithm

Demo comparing Classical Brute Force vs Qiskit Aer Simulator vs IBM Quantum Hardware for password cracking using Grover's algorithm.

🚀 Quick Start

1. Install Dependencies

pip install -r requirements.txt

2. Configure IBM Quantum Credentials

Add your IBM Quantum credentials in .env:

IBM_QUANTUM_TOKEN=7....
IBM_QUANTUM_INSTANCE=crn:.....

3. Run the Demo

python grover.py

📊 What It Does

The program will:

1. Auto-load your IBM Quantum credentials from .env
2. Connect to IBM Quantum and list available quantum computers
3. Prompt you to choose a backend (or use least busy)
4. Ask for a password to crack (2-3 characters recommended)
5. Run three methods:
   • Classical brute force (sequential search)
   • Qiskit Aer simulator (local quantum simulation)
   • IBM Quantum hardware (real quantum computer)
6. Compare results in a table

🎯 Example Usage

Enter password length (2-3 recommended): 2
Enter a 2-character password: Hi

Executing three methods:
  1. Classical brute force
  2. Qiskit Aer simulator (local)
  3. IBM Quantum hardware (ibm_brisbane)

⚡ Three-Way Comparison

You'll see output like:

Method               Result          Time                 Iterations/Attempts  Accuracy
--------------------------------------------------------------------------------
Classical            'Hi'            0.0045s              2,945                100%
Qiskit Aer (sim)     'Hi'            0.3241s              48                   98.2%
IBM ibm_brisbane     'Hi'            45.2341s             48                   87.5%

🔑 Key Insights

🔍 Why Low Accuracy? The main issue: Your 12-qubit, 48-iteration Grover circuit transpiled to 714,861 gates!

Real quantum computers have:

Gate errors: ~0.1-1% error per gate Decoherence: Qubits lose information over time With 714K gates: Error accumulates massively → random results

• Classical: Tries thousands of combinations sequentially
• Quantum: Only √N Grover iterations needed (huge speedup!)
• Aer: Simulates quantum operations (slow on classical hardware)
• IBM Quantum: Runs on real quantum computer (true quantum advantage)

⚠️ Important Notes

• Password Length: Use 2-3 characters for best results
  • 2 chars = ~3,844 combinations, 12 qubits, 48 Grover iterations
  • 3 chars = ~238,328 combinations, 18 qubits, 383 iterations
• IBM Queue Time: Real quantum hardware jobs may wait in queue
• Noise: Real quantum computers have decoherence/errors (lower accuracy)

📝 Files

• grover.py - Main quantum password cracker
• .env - IBM Quantum credentials (keep secret!)
• requirements.txt - Python dependencies
• README.md - This file

🔒 Security Note

DO NOT commit .env to GitHub! It contains your API credentials.

Add to .gitignore:

.env

🎓 Learn More

• IBM Quantum Documentation
• Qiskit Textbook
• Grover's Algorithm