This Python script simulates the process of secure key exchange using quantum cryptography. The simulator provides a graphical user interface (GUI) that allows users to type in their messages, encrypt them with QKD techniques, and observe the encrypted and decrypted outcomes.
- Quantum Key Distribution (QKD), a secure communication method that uses the properties of quantum mechanics to establish a shared secret key between two parties.
- Quantum Gates which are operations performed on qubits to manipulate their states, such as the Hadamard gate (H), Pauli gates (X, Y, Z), and measurement gates.
- Quantum Measurement to extract information from qubits into classical bits. This measurement collapses the superposition and provides classical information based on the qubit's state.
- Classical Communication for the exchange of classical information between two parties to compare measurement bases and sift the key.
- Error Correction to detect and correct errors introduced during the transmission of qubits.
- Privacy Amplification to distill a shorter, secure key from a longer sifted key. The simulator applies a hash function to the sifted key, reducing its size while maintaining its cryptographic strength.
- Hash Functions which are cryptographic algorithms that transform data into fixed-length values. The simulator utilises a hash function (SHA-256) to amplify privacy and generate a secure key from the sifted key.
- random module for random number generation.
- hashlib module for the SHA-256 hash function.
- qiskit library for quantum circuit simulation.
- tkinter library for GUI development.
- Initialisation. The necessary components, including a quantum circuit and a graphical user interface (GUI) using tkinter, are set up in the init method of the QKDSimulator class.
- Key Generation. The user enters a message through the GUI. The generate_random_key method generates a random key of 0s and 1s. The prepare_qubits method prepares the qubits in the quantum circuit using quantum gates and the key values.
- Qubit Exchange. The exchange_qubits_with_noise method simulates the exchange of qubits between two parties (Alicia and David) and introduces random errors (noise) to the qubits.
- Key Sifting. The compare_bases method compares the bases used by Alicia and David, identifying matching bases. The sift_key method sifts the key based on the indices of the matching bases.
- Eavesdropping Detection. The detect_eavesdropping method checks for potential eavesdropping by comparing the length of the sifted key with the number of matching bases. If they differ, potential eavesdropping is detected.
- Error Correction and Privacy Amplification. The error_correction method performs error correction on the sifted key, and the privacy_amplification method applies a hash function to reduce information leakage in the final key.
- Classical Communication. The classical_communication method converts the user's message into binary form (ASCII) and a list of bits.
- Message Encryption. The encrypt_message_bits method encrypts the message bits using a bitwise exclusive OR (XOR) operation with the sifted key.
- Message Decryption. The decrypt_message method decrypts the ciphertext by performing an XOR operation between the ciphertext and the sifted key.
- Output Display. The encrypted and decrypted messages, in ASCII format, are displayed in the GUI.
- Incorporating this into practical applications like messaging.
- Implementating advanced cryptography algorithms to address future security challenges.
- Implementating visualisation and analysis methods to analyse the quantum operations, measurement outcomes, and security properties of the simulated QKD process.
Contributions are welcome! Feel free to reach out with your suggestions, bug reports, or feature requests.
This project is licensed under the MIT License.