Overview

This Continuous-Variable Quantum Key Distribution (CV-QKD) simulation demonstrates the effectiveness of a wave attack on noise levels during quantum key distribution. The project allows a comparison between normal and attack scenarios, illustrating how the wave attack maintains low noise levels, thus showing its effectiveness in going undetected.

This simulation is inspired by concepts from the paper: Quantum Hacking on Quantum Key Distribution using Homodyne Detection.

Features

• Wave Attack Simulation: Simulates a wave attack to assess its effectiveness in maintaining noise levels similar to a normal scenario.
• Normal Scenario Comparison: Provides a baseline noise comparison without attack.
• Noise Calculation: Calculates noise levels under randomized attenuation conditions, giving realistic noise distributions.
• Statistical Output: Outputs mean noise levels and standard deviation for both normal and attack scenarios.

Requirements

Install the required packages via pip:

pip install pennylane numpy

Usage

1. Run the Simulation: Use the provided code to simulate noise in both normal and attack scenarios.

   # Run simulations for normal and wave attack scenarios
   normal_noises = simulate_scenario(alpha_vals, wavelengths["normal"])
   attack_noises = simulate_scenario(alpha_vals, wavelengths["wave_attack"])
   

2. Analyze the Results: The code prints the mean and standard deviation of noise for each scenario, allowing you to observe how the wave attack maintains similar noise levels to the normal scenario.

   print(f'--- Normal Scenario ---')
   print(f'Mean Noise Level: {np.mean(normal_noises):.4f}')
   print(f'Standard Deviation of Noise: {np.std(normal_noises):.4f}')
   
   print(f'\n--- Wave Attack Scenario ---')
   print(f'Mean Noise Level: {np.mean(attack_noises):.4f}')
   print(f'Standard Deviation of Noise: {np.std(attack_noises):.4f}')
   

Functions

• calculate_noise: Computes noise based on channel efficiency, shot noise, and attenuation ratios.
• measure_x_quadrature & measure_p_quadrature: Separate QNodes for measuring quadrature values under specified transmittance conditions.
• simulate_scenario: Conducts the main simulation, calculating noise levels for either normal or wave attack scenarios.

Example Output

Sample output from the simulation:

--- Normal Scenario ---
Mean Noise Level: 0.5123
Standard Deviation of Noise: 0.0234

--- Wave Attack Scenario ---
Mean Noise Level: 0.5121
Standard Deviation of Noise: 0.0232