def test_diffie_hellman_exchange(self):
"""
Simulates a diffie-hellman key exchange
"""
# Alice and Bob agree for a secure generator and prime
base, modulus = Math.generate_generator_and_prime(128)
alice = DiffieHellman(base, modulus)
bob = DiffieHellman(base, modulus)
# Alice calculates her exponentiation
alice_result = alice.get_result()
# Bob calculates his exponentiation
bob_result = bob.get_result()
# so, they exchange the result and calculates the shared secret
secret_alice = alice.calculate_shared_secret(bob_result)
secret_bob = bob.calculate_shared_secret(alice_result)
# And if right, both secrets must be equal.
self.assertEqual(secret_alice, secret_bob)
def __establish_session(self, con):
generator, prime = self.__receive_generator_and_prime(con)
diffie_hellman = DiffieHellman(generator, prime)
result = diffie_hellman.get_result()
result_from_client = int(con.recv(1024))
con.send(bytes(str(result), 'utf8'))
self.__key = diffie_hellman.calculate_shared_secret(result_from_client)
self.__session_estabilished = True
print("Session key: " + str(self.__key))
self.__key = self.__key.to_bytes(32, byteorder = "big")
self.__aes = pyaes.AESModeOfOperationCTR(self.__key)
def establish_session(self):
generator, prime = Math.generate_generator_and_prime(256)
self.__tcp_client.send(bytes(str(generator), 'utf8'))
self.__tcp_client.send(bytes(str(prime), 'utf8'))
diffie_hellman = DiffieHellman(generator, prime)
result = diffie_hellman.get_result()
self.__tcp_client.send(bytes(str(result), 'utf8'))
result_from_server = int(self.__tcp_client.recv(1024))
self.__key = diffie_hellman.calculate_shared_secret(result_from_server)
print("Session key: " + str(self.__key))
self.__key = self.__key.to_bytes(32, byteorder="big")
self.__aes = pyaes.AESModeOfOperationCTR(self.__key)
