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ac:laboratoare:11 [2025/11/06 10:29] marios.choudary |
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| For this you can either modify the work you did above to use a post-quantum key exchange method such as ML-KEM in Python. | For this you can either modify the work you did above to use a post-quantum key exchange method such as ML-KEM in Python. | ||
| + | To do this in Python you can use a library such as [[https://pypi.org/project/mlkem/|ml-kem]]. | ||
| + | You can install this as follows: | ||
| + | <code> | ||
| + | pip install ml-kem | ||
| + | </code> | ||
| + | |||
| + | Below is an example of how to use this library in a simple client-server scenario. Note: this example is provided by Gemini AI, so use it with caution and double-check it: | ||
| + | <code> | ||
| + | # Install the library first: pip install ml-kem | ||
| + | |||
| + | from mlkem.ml_kem import ML_KEM | ||
| + | from mlkem.parameter_set import ML_KEM_768 # Recommended security level | ||
| + | import secrets | ||
| + | |||
| + | # --- Server (Alice) Side --- | ||
| + | |||
| + | def server_keygen(): | ||
| + | """Alice generates her ML-KEM key pair.""" | ||
| + | # Initialize ML-KEM with the desired security level | ||
| + | ml_kem = ML_KEM(parameters=ML_KEM_768, randomness=secrets.token_bytes) | ||
| + | | ||
| + | # Generate the encapsulation key (ek, public) and decapsulation key (dk, private) | ||
| + | ek, dk = ml_kem.key_gen() | ||
| + | | ||
| + | print("Alice: Generated Public Key (ek) and Private Key (dk).") | ||
| + | return ek, dk, ml_kem | ||
| + | |||
| + | def server_decapsulate(dk, c, ml_kem): | ||
| + | """Alice decapsulates the ciphertext to get the shared secret.""" | ||
| + | try: | ||
| + | K_prime = ml_kem.decaps(dk, c) | ||
| + | print("Alice: Successfully decapsulated the Shared Secret (K').") | ||
| + | return K_prime | ||
| + | except ValueError as e: | ||
| + | print(f"Alice: Decapsulation failed! {e}") | ||
| + | return None | ||
| + | |||
| + | # --- Client (Bob) Side --- | ||
| + | |||
| + | def client_encapsulate(ek): | ||
| + | """Bob encapsulates a shared secret using Alice's public key.""" | ||
| + | ml_kem = ML_KEM(parameters=ML_KEM_768, randomness=secrets.token_bytes) | ||
| + | | ||
| + | # Encapsulate to get the shared secret (K) and the ciphertext (c) | ||
| + | K, c = ml_kem.encaps(ek) | ||
| + | | ||
| + | print("Bob: Encapsulated a Shared Secret (K) and created Ciphertext (c).") | ||
| + | return K, c | ||
| + | |||
| + | # --- Communication Flow Simulation --- | ||
| + | |||
| + | # 1. Server (Alice) Key Generation | ||
| + | ek_server, dk_server, ml_kem_instance = server_keygen() | ||
| + | |||
| + | # 2. Public Key Transmission (ek_server is sent to the client) | ||
| + | print("\n--- Network Transmission: ek sent to Bob ---") | ||
| + | |||
| + | # 3. Client (Bob) Encapsulation | ||
| + | K_client, c_client = client_encapsulate(ek_server) | ||
| + | |||
| + | # 4. Ciphertext Transmission (c_client is sent back to the server) | ||
| + | print("\n--- Network Transmission: c sent to Alice ---") | ||
| + | |||
| + | # 5. Server (Alice) Decapsulation | ||
| + | K_server = server_decapsulate(dk_server, c_client, ml_kem_instance) | ||
| + | |||
| + | # 6. Verification | ||
| + | print("\n--- Verification ---") | ||
| + | if K_client is not None and K_server is not None: | ||
| + | if K_client == K_server: | ||
| + | print("Success! Alice's and Bob's shared secrets match.") | ||
| + | # The shared secret can now be used as an AES key, e.g., K_client | ||
| + | # The shared secret is bytes: | ||
| + | # print(f"Shared Secret: {K_client.hex()}") | ||
| + | else: | ||
| + | print("Failure! Shared secrets do not match.") | ||
| + | else: | ||
| + | print("Failure in key exchange process.") | ||
| + | </code> | ||
| + | |||
| Otherwise, you can start from the Diffie-Hellman key exchange lab we did in OpenSSL/C. You may start from {{:ac:laboratoare:lab_dhe_solved.zip|this}} code, that provides a working solution for the Diffie-Hellman lab in OpenSSL. | Otherwise, you can start from the Diffie-Hellman key exchange lab we did in OpenSSL/C. You may start from {{:ac:laboratoare:lab_dhe_solved.zip|this}} code, that provides a working solution for the Diffie-Hellman lab in OpenSSL. | ||
