class TestDiffieHellman(unittest.TestCase):
def setUp(self):
self.alice = DiffieHellman()
self.bob = DiffieHellman()
def test_equality_of_keys(self):
self.alice.generate_public_key()
self.bob.generate_public_key()
alices_shared_key = self.alice.generate_shared_secret(self.bob.public_key)
bobs_shared_key = self.bob.generate_shared_secret(self.alice.public_key)
self.assertEqual(alices_shared_key, bobs_shared_key,
"There is a mismatch between two shared secrets. Both shared secrets should be the same. This is bad.")
def test_decorators_private_key(self):
self.alice.generate_public_key()
self.assertIn("_DiffieHellman__private_key", self.alice.__dict__)
def test_generate_private_key(self):
self.alice.generate_private_key()
self.assertIn("_DiffieHellman__private_key", self.alice.__dict__)
def test_generate_public_key(self):
self.alice.generate_public_key()
self.assertIn("public_key", self.alice.__dict__)
def test_verify_public_key(self):
self.alice.generate_public_key()
self.bob.generate_public_key()
self.assertTrue(self.alice.verify_public_key(self.bob.public_key))
self.assertFalse(self.alice.verify_public_key(2))
self.assertFalse(self.alice.verify_public_key(self.alice.prime - 1))
class Node:
def __init__(self, node_id):
self.node_id = node_id
self.authorised_users = []
self.transaction_history = []
# Set up crypto
self.diffie = DiffieHellman()
self.exchange_keys()
self.sync()
print("Node Established.")
def sync(self):
conn = socket.socket()
conn.connect((SERVER_IP, SERVER_PORT))
conn.send(self.crypt(b"SYNC"))
def update_authorised_users(self):
pass
def send_transactions(self):
pass
def main_loop(self):
pass
def exchange_keys(self):
self.diffie.generate_public_key()
conn = socket.socket()
conn.connect((SERVER_IP, SERVER_PORT))
conn.send(self.crypt(self.node_id.zfill(8).encode()))
conn.send(b"KEYX")
key_len = str(len(str(self.diffie.public_key))).zfill(4).encode()
conn.send(key_len)
conn.send(str(self.diffie.public_key).encode())
server_key_len = int(conn.recv(4))
server_key = int(conn.recv(server_key_len))
self.diffie.generate_shared_secret(server_key)
conn.close()
def crypt(self, text):
key = self.diffie.shared_key
if type(text) == str:
text = text.encode()
if type(key) == str:
key = key.encode()
assert type(text) == type(key) == bytes
output_values = []
for i, b in enumerate(text):
output_values.append(b ^ key[i % len(key)])
return bytes(output_values)
class MessangerClient(asyncore.dispatcher):
def __init__(self, host, port, login, password):
asyncore.dispatcher.__init__(self)
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
self.connect((host, port))
self.login = login
self.password = password
self.Key = DiffieHellman()
self.Key.generate_public_key()
self.buffer = json.dumps({'action': 'handshake', 'data': {'pubkey': int_to_base_str(self.Key.public_key)}}).encode()
self.cipher = None
def handle_connect(self):
pass
def handle_close(self):
self.close()
def handle_read(self):
data = self.recv(4024).decode('utf-8')
if data:
if self.cipher is not None:
j = json.loads(self.cipher.decrypt(data))
else:
j = json.loads(data)
print(j)
if j["action"] == "handshake":
tmp = base_str_to_int(j["data"]["pubkey"])
h = SHA.new(j["data"]["pubkey"].encode()).digest()
self.Key.generate_shared_secret(tmp)
SignR = int(j["data"]["SignR"])
SignS = int(j["data"]["SignS"])
if not ElGamalKey.verify(h, (SignR, SignS)):
raise("BAD SIGNATURE")
self.cipher = AESCipher(str(self.Key.shared_key).encode())
self.buffer = json.dumps({'action': 'auth', 'data': {'login': login, 'pass': password}}).encode('utf-8')
def writable(self):
return len(self.buffer) > 0
def handle_write(self):
if self.cipher is not None:
sent = self.send(self.cipher.encrypt(self.buffer.decode()))
self.buffer = self.buffer[sent:]
else:
sent = self.send(self.buffer)
self.buffer = self.buffer[sent:]
def main():
"""Main loop
See vpn.md for details
"""
# Create the socket
server_sckt = socket(AF_INET, SOCK_STREAM)
server_sckt.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
server_sckt.bind((HOST, PORT))
server_sckt.listen()
print(f"Listening on {HOST}:{PORT}")
conn, client = server_sckt.accept()
print(f"New client: {client[0]}:{client[1]}")
# Negotiating the cipher
print("Negotiating the cipher")
msg_in = conn.recv(4096).decode('utf-8')
proposed = parse_proposal(msg_in)
cipher_name, key_size = select_cipher(SUPPORTED_CIPHERS, proposed)
print(f"We are going to use {cipher_name}{key_size}")
msg_out = generate_cipher_response(cipher_name, key_size)
conn.send(msg_out.encode())
# Negotiating the key
print("Negotiating the key")
dh = DiffieHellman()
dh.generate_public_key()
msg_in = conn.recv(4096).decode('utf-8')
client_public_key = parse_dhm_request(msg_in)
dh.generate_shared_secret(client_public_key)
msg_out = generate_dhm_response(dh.public_key)
conn.send(msg_out.encode())
cipher, key, iv = get_key_and_iv(dh.shared_key, cipher_name, key_size)
print("The key has been established")
print("Initializing cryptosystem")
crypto = cipher.new(key, cipher.MODE_CBC, iv)
hashing = HMAC.new(key, digestmod=SHA256)
print("All systems ready")
while True:
msg_in = conn.recv(4096)
if len(msg_in) < 1:
conn.close()
break
msg, hmac = read_message(msg_in, crypto)
validate_hmac(msg_in, hmac, hashing)
print(f"Received: {msg}")
msg_out = f"Server says: {msg[::-1]}"
conn.send(msg_out.encode())
def main():
"""Main event loop
See vpn.md for details
"""
# Start the server
client_sckt = socket(AF_INET, SOCK_STREAM)
client_sckt.connect((HOST, PORT))
print(f"Connected to {HOST}:{PORT}")
# Negotiating the cipher
print("Negotiating the cipher")
# Send proposal to the server
msg_out = generate_cipher_proposal(SUPPORTED_CIPHERS)
client_sckt.send(msg_out.encode())
msg_in = client_sckt.recv(4096).decode('utf-8')
cipher_name, key_size = parse_cipher_selection(msg_in)
print(f"We are going to use {cipher_name}{key_size}")
# Negotiating the key
print("Negotiating the key")
dh = DiffieHellman()
dh.generate_public_key()
msg_out = generate_dhm_request(dh.public_key)
client_sckt.send(msg_out.encode())
msg_in = client_sckt.recv(4096).decode('utf-8')
server_public_key = parse_dhm_response(msg_in)
dh.generate_shared_secret(server_public_key)
cipher, key, iv = get_key_and_iv(dh.shared_key, cipher_name, key_size)
print("The key has been established")
# Initialize Cryptosystem
print("Initializing cryptosystem")
crypto = cipher.new(key, cipher.MODE_CBC, iv)
hashing = HMAC.new(key, digestmod=SHA256)
print("All systems ready")
while True:
msg = input("Enter message: ")
if msg == "\\quit":
client_sckt.close()
break
ciph_out, hmac_out = encrypt_message(msg, crypto, hashing)
client_sckt.send(ciph_out + hmac_out.encode())
msg_in = client_sckt.recv(4096)
print(msg_in.decode("utf-8"))
def key_exchange(self, conn, addr):
diffie = DiffieHellman()
diffie.generate_public_key()
public_key = diffie.public_key
key_to_send = str(public_key).encode()
key_len = str(len(key_to_send)).zfill(4).encode()
client_key_len = int(conn.recv(4))
client_key = int(conn.recv(client_key_len))
conn.send(key_len)
conn.send(key_to_send)
diffie.generate_shared_secret(client_key)
client_id = crypt(conn.recv(8), diffie.shared_key).decode()
conn.close()
self.store_node(client_id, addr, diffie.shared_key)
def session(self):
alice = DiffieHellman(group=5, key_length=200)
alice.generate_public_key()
self.Message_send.message = str(alice.public_key)
# send puzzle answer and ga mod p
self.send_message()
# receive the session key of server
self.receive_message()
alice.generate_shared_secret(int(self.Message_rec.gb_mod_p))
# set up the session key Kas
self.Kas = str(alice.shared_secret)[:16].encode()
self.iv = self.Message_rec.iv
# print("Shared secret is:", int.from_bytes(self.Kas, sys.byteorder))
# Decryption
plain_text = self.decryption_with_timestamp()
# Verify signature
correct_message = str(
alice.public_key) + "|" + self.Message_rec.gb_mod_p
correct_message = correct_message.encode()
## load public key
with open("public_key.der", "rb") as key_file:
public_key = serialization.load_der_public_key(
key_file.read(), backend=default_backend())
## verify the signature
try:
public_key.verify(
plain_text, correct_message,
paddings.PSS(mgf=paddings.MGF1(hashes.SHA256()),
salt_length=paddings.PSS.MAX_LENGTH),
hashes.SHA256())
# print("Signature verify success!")
except:
print('Error in verifying the signature!')
sys.exit(1)
class TestDiffieHellman(unittest.TestCase):
def setUp(self):
self.alice = DiffieHellman()
self.bob = DiffieHellman()
def test_equality_of_keys(self):
self.alice.generate_public_key()
self.bob.generate_public_key()
alices_shared_key = self.alice.generate_shared_secret(
self.bob.public_key)
bobs_shared_key = self.bob.generate_shared_secret(
self.alice.public_key)
self.assertEqual(
alices_shared_key, bobs_shared_key,
"There is a mismatch between two shared secrets. Both shared secrets should be the same. This is bad."
)
def test_decorators_private_key(self):
self.alice.generate_public_key()
self.assertIn("_DiffieHellman__private_key", self.alice.__dict__)
def test_generate_private_key(self):
self.alice.generate_private_key()
self.assertIn("_DiffieHellman__private_key", self.alice.__dict__)
def test_generate_public_key(self):
self.alice.generate_public_key()
self.assertIn("public_key", self.alice.__dict__)
def test_verify_public_key(self):
self.alice.generate_public_key()
self.bob.generate_public_key()
self.assertTrue(self.alice.verify_public_key(self.bob.public_key))
self.assertFalse(self.alice.verify_public_key(2))
self.assertFalse(self.alice.verify_public_key(self.alice.prime - 1))
class Sender:
def __init__(self):
self._sock_to_receiver = socket.socket(socket.AF_INET,
socket.SOCK_STREAM)
self._sock_to_mb = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self._df = DiffieHellman()
self._df.generate_private_key()
self._df.generate_public_key()
self._session_key = None
self._k = None
self._k_rand = None
def connect(self, address):
"""
The sender(S) in this connect method will attempt to connect
to the receiver(R) by a regular sock connection. If the
connection is set up successfully, S and R will execute a key
exchange protocol then both of them will get a shared secret
key. After that three keys (a session key Kssl, a key K used in our
detection protocol, and a key Krand used as a seed) will be derived
from this secret key. Then, S will try to connect to the middle-
box by another regular sock connection. If the connection is
set up successfully, S will execute a secure computation with MB
so that MB can obtain rules encrypted with key K without knowing K.
:param address: the receiver's address
:return:
"""
try:
self._sock_to_receiver.connect(address)
except socket.error as error:
print(f'Could not connect with the receiver: {error}')
exit(1)
except TypeError as error:
print(f'Type error: {error}')
exit(1)
else:
self._key_exchange(self._df.public_key)
self._derive_from_secret()
print('session key', self._session_key)
try:
self._sock_to_mb.connect(BLINDBOX_ADDRESS)
except socket.error as error:
print(f'Could not connect with blindBox: {error}')
exit(1)
except TypeError as error:
print(f'Type error: {error}')
exit(1)
else:
self._rule_preparation()
def _key_exchange(self, public_key):
"""
After a key exchange using Diffie-Hellman algorithm,
the sender will agree on a shared secret with the receiver.
:param public_key: The sender's public key for key exchange.
:return: None
"""
key_to_bytes = str(public_key).encode()
self._sock_to_receiver.sendall(key_to_bytes)
data = self._sock_to_receiver.recv(20480)
print(f'data received from the receiver {data}')
try:
pk_from_receiver = int(data)
except ValueError:
print('Invalid data type!')
else:
if self._df.verify_public_key(pk_from_receiver):
self._df.generate_shared_secret(pk_from_receiver)
print('I got the shared key:', self._df.shared_key)
else:
raise ValueError('Invalid public key from the sender!')
def _derive_from_secret(self):
"""
Use the shared key to derive three keys by using a pseudorandom
generator.
_session_key: used to encrypt the traffic in the socket.
_k: used in the detection protocol
_k_rand: used as a seed for randomness. Since both end-points have the same seed,
they will generate the same randomness.
:return: None
"""
key_to_bytes = str(self._df.shared_key).encode()
randoms = Randoms()
self._session_key = derive_key(key_to_bytes, randoms.random1)
self._k = derive_key(key_to_bytes, randoms.random2)
self._k_rand = derive_key(key_to_bytes, randoms.random3)
def _rule_preparation(self):
"""
Sender will use garbled circuits to compute AES(r,k) with the BlindBox while
the sender do not know the rule and the BlindBox do not know the key k.
:return:
"""
key_numbers = int(self._sock_to_mb.recv(1024))
for i in range(key_numbers):
output = subprocess.getoutput(OBLIVC_AES_PATH + "/a.out 1235 -- " +
self._k.decode())
while output == "TCP accept failed":
output = subprocess.getoutput(OBLIVC_AES_PATH +
"/a.out 1235 -- " +
self._k.decode())
def send(self, data):
encrypted_data = aes_encrypt(data.encode(), self._session_key)
self._sock_to_mb.sendall(encrypted_data)
sleep(0.4)
tokens = nltk.word_tokenize(data)
encrypted_tokens = b''
for token in tokens:
encrypted_tokens += dpi_encrypt(token.encode(), self._session_key)
encrypted_tokens += b' '
self._sock_to_mb.sendall(encrypted_tokens)
class Client:
def __init__(self, node_table):
self.next_node = ""
self.id = "client"
self.node_table = node_table
self.send_ops = {
OP.CREATE: self.get_create_packet,
OP.EXTEND: self.get_extend_packet
}
self.setup_keys()
self.connect_to_signals()
def setup_keys(self):
self.aes_keys = {}
self.dhke = DiffieHellman()
self.dhke.generate_public_key()
self.dh_pub = str(self.dhke.public_key).encode('utf8')
self.__dh_sharedkey = None
def connect_to_signals(self):
dispatcher.connect(self.handle_created, signal=OP.CREATED, sender=dispatcher.Any)
dispatcher.connect(self.handle_extended, signal=OP.EXTENDED, sender=dispatcher.Any)
dispatcher.connect(self.handle_extended, signal=OP.EXTEND, sender=dispatcher.Any)
def get_create_packet(self, receivers):
iniciopKp=time.time()
receiver = self.node_table[receivers[0]]
msg = self.dh_pub
enc_msg = rsa.encrypt(msg, receiver.pubkey)
packet = Packet(src_id="client", op=OP.CREATE,
dest=receiver.id, payload=(enc_msg, None))
print("client: Sending CREATE packet to {}".format(receiver))
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
return packet
def send_message(self, receivers, op):
iniciopKp=time.time()
receivers = receivers.split()
self.next_node = receivers[len(receivers) - 1]
packet = self.send_ops[op](receivers)
dispatcher.send(signal=op, sender=self, packet=packet)
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
def handle_created(self, packet):
if packet.dest != self.id:
return
iniciopKp=time.time()
print("client: Handling CREATED packet from {}".format(packet.src))
(other_key, key_hash) = packet.msg
# Generate the shared key
self.dhke.generate_shared_secret(other_key)
shared = self.dhke.shared_key
m_key_hash = hashlib.sha1(str(shared).encode("utf-8")).hexdigest()
if m_key_hash == key_hash:
print("{}: DH Hash Comparison from {} SUCCESS".format(self.id, packet.src))
self.__dh_sharedkey = shared
self.aes_keys[packet.src] = shared
print("client: Entry node is now set to: ", self.next_node)
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
return
print("{}: DH Hash Comparison from {} FAIL".format(self.id, packet.src))
def handle_extended(self, packet):
if packet.dest != self.id:
return
iniciopKp=time.time()
print("client: Handling CREATED packet from {}".format(packet.src))
if not packet.decrypt_aes(self.aes_keys[packet.src]):
print("{}: Decryption of EXTENDED packet from {} FAIL".format(self.id, packet.src))
return
print("{}: Decryption of EXTENDED packet from {} SUCCESS".format(self.id, packet.src))
(other_key, key_hash) = tuple(packet.msg.split('|||'))
other_key = int(other_key)
key_hash = key_hash.strip()
self.dhke.generate_shared_secret(other_key)
shared = self.dhke.shared_key
m_key_hash = hashlib.sha1(str(shared).encode("utf-8")).hexdigest()
if m_key_hash == key_hash: # Only go through if hash matches
print("{}: DH Hash Comparison from {} SUCCESS".format(self.id, packet.src))
self.__dh_sharedkey = shared
self.aes_keys[packet.src] = shared
print("client: Connection established with {}".format(self.next_node))
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
return
print("{}: DH Hash Comparison from {} FAIL".format(self.id, packet.src))
# Extend always gets wrapped with everything in the the AES Keys list
def get_extend_packet(self, receivers):
msg = "Type: Extend"
iniciopKp=time.time()
extend_messages = {}
for j in range(len(receivers) - 1):
extend_messages[receivers[j]] = aes_encrypt(msg, self.aes_keys[receivers[j]])
def recursive_extend(recs, node_index):
if node_index == len(recs) - 1:
create_packet = self.get_create_packet(recs[node_index:])
create_packet.src = recs[node_index - 1]
return create_packet
return Packet(src_id="client", op=OP.EXTEND, dest=recs[0],
payload=(extend_messages[recs[node_index]], recursive_extend(recs, node_index + 1)))
packet = recursive_extend(receivers, 0)
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
return packet
def login_proto(self):
print("something")
Message = COMM_MESSAGE()
data, temp = self.connection_from_client.recvfrom(4096)
print(temp)
Message.ParseFromString(data)
if Message.type == Message.TYPE.LOGIN:
N1 = os.urandom(16)
N1 = N1.hex()
print(N1)
digest = sha256()
digest.update(N1.encode())
Message.N1_hash = digest.hexdigest()
Message.message = N1[5:]
self.connection_from_client.sendall(Message.SerializeToString())
data, temp = self.connection_from_client.recvfrom(4096)
print(temp)
Message.ParseFromString(data)
if Message.N1 == N1:
print("Puzzle figured out!")
else:
print("Wrong!")
bob = DiffieHellman(group=5, key_length=200)
bob.generate_public_key()
Message.gb_mod_p = str(bob.public_key)
bob.generate_shared_secret(int(Message.message))
Kas = str(bob.shared_secret)[:16].encode()
# Kas = (bob.shared_secret).to_bytes(16,sys.byteorder)
print("Shared secret is:", int.from_bytes(Kas, sys.byteorder))
Message.gb_mod_p = str(bob.public_key)
#### loading private key
with open("private_key.pem", "rb") as key_file:
private_key = serialization.load_pem_private_key(
key_file.read(), password=None, backend=default_backend())
#### encryption
plain_text_sign = Message.message + "|" + Message.gb_mod_p
plain_text_sign = plain_text_sign.encode()
### sign the text
signature = private_key.sign(
plain_text_sign,
paddings.PSS(mgf=paddings.MGF1(hashes.SHA256()),
salt_length=paddings.PSS.MAX_LENGTH),
hashes.SHA256())
#### Timestamp
timestamp = str(int(time.time()))
timestamp = timestamp.encode()
plain_text = signature + timestamp
iv = os.urandom(16)
Message.iv = iv
padder = padding.PKCS7(128).padder()
padded_data = padder.update(plain_text)
padded_data += padder.finalize()
plain_text_padded = padded_data
authenticate_data = b'Final Project'
# self.Message.authenticate_data = authenticate_data
# GCM Mode, we also need an IV
# encrypt
cipher = Cipher(algorithms.AES(Kas),
modes.GCM(iv),
backend=default_backend())
encryptor = cipher.encryptor()
encryptor.authenticate_additional_data(authenticate_data)
cipher_text = encryptor.update(
plain_text_padded) + encryptor.finalize()
Message.cipher_text = cipher_text
Message.tag = encryptor.tag
self.connection_from_client.sendall(Message.SerializeToString())
### Decrypt and verify the client:
data = self.connection_from_client.recv(4096)
Message.ParseFromString(data)
# AES decryption
decryptor = Cipher(algorithms.AES(Kas),
modes.GCM(iv, Message.tag),
backend=default_backend()).decryptor()
decryptor.authenticate_additional_data(authenticate_data)
decrypted_plain_text = decryptor.update(
Message.cipher_text) + decryptor.finalize()
# unpad
unpadder = padding.PKCS7(128).unpadder()
plain_text = unpadder.update(
decrypted_plain_text) + unpadder.finalize()
# Verify timestamp
plain_text_timestamp = plain_text[-10:]
message_timestamp = int(plain_text_timestamp)
if ((int(time.time()) - message_timestamp) < 60):
print("Timestamp verified")
else:
print("Timestamp failed!")
###
plain_text = plain_text[0:len(plain_text) - 10]
plain_text = plain_text.decode()
username = plain_text.split("|")[0]
password = plain_text.split("|")[1]
#if username == "Yushen" and password == "123":
# verify = "Success"
#else:
# verify = "Fail"
verify = "Fail"
if username in self.identities.keys():
pass_digest = sha256()
pass_digest.update(password.encode())
pass_digest.update(self.identities[username]["salt"].encode())
pass_hash = pass_digest.hexdigest()
print(pass_hash, "is the passhash")
if pass_hash == self.identities[username]["passhash"]:
verify = "Success"
####
plain_text = verify.encode()
timestamp = str(int(time.time()))
timestamp = timestamp.encode()
plain_text = plain_text + timestamp
padder = padding.PKCS7(128).padder()
padded_data = padder.update(plain_text)
padded_data += padder.finalize()
plain_text_padded = padded_data
cipher = Cipher(algorithms.AES(Kas),
modes.GCM(iv),
backend=default_backend())
encryptor = cipher.encryptor()
encryptor.authenticate_additional_data(authenticate_data)
cipher_text = encryptor.update(
plain_text_padded) + encryptor.finalize()
Message.cipher_text = cipher_text
Message.tag = encryptor.tag
self.connection_from_client.sendall(Message.SerializeToString())
# connection_from_client.shutdown(0)
# self.socket_from_client.shutdown(0)
self.connection_from_client.close()
self.socket_from_client.close()
BS = 16
unpad = lambda s: s[:-ord(s[len(s) - 1:])]
pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS)
while True:
#ta emot nytt meddelande
data, addr = sock.recvfrom(4096)
temp = data.decode()
#handshake
if temp.startswith("Handshake,"):
data = temp.split(",")[1]
sock.sendto(str(bob.public_key).encode(), (UDP_IP, 13000))
print("Public key of Server:", bob.public_key)
print("Public key of Client:", data)
test = int(data)
bob.generate_shared_secret(test, echo_return_key=True)
hash = SHA256.new()
hash.update(str(bob.shared_key).encode())
hash = hash.digest()
print("Symmetric shared key: ", bob.shared_key)
session, addr = sock.recvfrom(4096)
session = decrypt(session)
print("Sesssion number:", session.decode('utf-8'))
session_number = 1
else:
print("------------------------------------")
print("Meddelande innan decode: ", data.decode('utf-8'))
data = decrypt(data)
if data.startswith(session):
session_number_msg = str(data.decode('utf-8')).split(",")[2]
#!/usr/bin/env python3 # -*- coding: utf-8 -*- from diffiehellman.diffiehellman import DiffieHellman alice = DiffieHellman(group=18, key_length=1024) bob = DiffieHellman(group=18, key_length=1024) alice.generate_public_key() # automatically generates private key bob.generate_public_key() alice.generate_shared_secret(bob.public_key, echo_return_key=True) bob.generate_shared_secret(alice.public_key, echo_return_key=True) a = alice.shared_key b = bob.shared_key
def encrypt(raw):
raw = pad(raw)
iv = Random.new().read(AES.block_size)
cipher = AES.new(hash, AES.MODE_CBC, iv)
return base64.b64encode(iv + cipher.encrypt(raw.encode("utf8")))
#--------------------------------------------------------------------------------------------------------
#sock setup
sock = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
sock.bind((UDP_IP, 13000))
#Handshake
sock.sendto(("Handshake,"+str(alice.public_key)).encode(), (UDP_IP, UDP_PORT))
data, addr = sock.recvfrom(4096)
test = int(data.decode())
alice.generate_shared_secret(test,echo_return_key=True)
print(alice.shared_key)
hash = SHA256.new()
hash.update(str(alice.shared_key).encode())
hash = hash.digest()
session = random.getrandbits(128)
print(session)
test = pad(str(session))
iv = Random.new().read( AES.block_size )
obj = AES.new(hash,AES.MODE_CBC, iv)
encrypted_message = base64.b64encode(iv + obj.encrypt(test.encode("utf8")))
print(encrypted_message)
sock.sendto(encrypted_message, (UDP_IP, UDP_PORT))
session_number=1
while True:
message = input("Send message")
def client_setup_connection(self, dest):
client_sk = socket.socket()
client_sk.connect(('127.0.0.1', int(self.user_online[dest][1])))
self.socket_list[dest] = []
self.socket_list[dest].append(client_sk)
port = client_sk.getsockname()[1]
# print ("Port is:", port)
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.bind(("127.0.0.1", port))
#########################
### Set up ######
### the connection ######
#########################
MessageSend = COMM_MESSAGE()
MessageRec = COMM_MESSAGE()
MessageSend.type = COMM_MESSAGE.TYPE.CLIENT_TO_CLIENT
MessageSend.ticket = self.user_online[dest][4]
MessageSend.ticket_tag = self.user_online[dest][5]
kabtemp = self.user_online[dest][2].encode()
ivtemp = self.user_online[dest][3].encode()
y = os.urandom(8)
x = y.hex()
N1 = int(x, 16)
plain_text = str(N1).encode() + str(int(time.time())).encode()
MessageSend = self.encryption_in_client(MessageSend, kabtemp, ivtemp,
plain_text)
self.socket_list[dest][0].sendall(MessageSend.SerializeToString())
data = self.socket_list[dest][0].recv(4096)
MessageRec.ParseFromString(data)
plain_text = self.decryption_with_timestamp_in_client(
MessageRec, kabtemp, ivtemp)
plain_text = plain_text.decode()
N1_rec = int(plain_text.split(" ")[0])
if N1 - 1 == N1_rec:
MessageSend = COMM_MESSAGE()
MessageSend.type = COMM_MESSAGE.TYPE.CLIENT_TO_CLIENT
### Set up the new Kab ###
alice = DiffieHellman(group=5, key_length=200)
alice.generate_public_key()
MessageSend.message = str(alice.public_key)
alice.generate_shared_secret(int(MessageRec.gb_mod_p))
# set up the session key Kas
self.socket_list[dest].append(
str(alice.shared_secret)[:16].encode())
N2_rec = int(plain_text.split(" ")[1])
N2_send = N2_rec - 1
plain_text = str(N2_send).encode() + str(int(time.time())).encode()
MessageSend.iv = self.user_online[dest][3].encode()
MessageSend = self.encryption_in_client(MessageSend, kabtemp,
ivtemp, plain_text)
self.socket_list[dest][0].sendall(MessageSend.SerializeToString())
data = self.socket_list[dest][0].recv(4096)
MessageRec.ParseFromString(data)
plain_text = self.decryption_with_timestamp_in_client(
MessageRec, self.socket_list[dest][1], MessageRec.iv)
plain_text = plain_text.decode()
if plain_text.split(" ")[0] == "Confirm" and plain_text.split(
" ")[1] == dest:
self.socket_list[dest].append(MessageRec.iv)
plain_text = ("Confirm " + self.client_name).encode() + str(
int(time.time())).encode()
MessageSend = COMM_MESSAGE()
MessageSend.type = COMM_MESSAGE.TYPE.CLIENT_TO_CLIENT
MessageSend.iv = self.socket_list[dest][2]
self.socket_list[dest].append(server)
client_thread_listen_from_existing_connection = threading.Thread(
target=self.listen_from_existed_connection,
args=(dest, )) # 把sock 加入线程内
client_thread_listen_from_existing_connection.start() # 启动线程
MessageSend = self.encryption_in_client(
MessageSend, self.socket_list[dest][1],
self.socket_list[dest][2], plain_text)
self.socket_list[dest][0].sendall(
MessageSend.SerializeToString())
# print ("I have succeed in setting up connection with", dest)
# print("We use this socket to chatting:", self.socket_list[dest][0])
else:
print("Set up connection with", dest, "failed!")
sys.exit(1)
else:
print("N1 verify failed!")
sys.exit(1)
class Node:
def __init__(self, id):
self.setup_keys()
self.connect_to_signals()
self.id = id
self.send_ops = {
OP.CREATED: self.get_created_packet,
OP.EXTENDED: self.get_extended_packet
}
self.hop_table = {1: HopPair(prev=None, next=None)}
def setup_keys(self):
self.dhke = DiffieHellman(key_length=1024)
self.dhke.generate_public_key()
self.__dh_sharedkey = None
self.dh_pub = str(self.dhke.public_key).encode('utf8')
(self.pubkey, self.__privkey) = rsa.newkeys(1024)
def connect_to_signals(self):
dispatcher.connect(self.handle_extend, signal=OP.EXTEND, sender=dispatcher.Any)
dispatcher.connect(self.handle_create,
signal=OP.CREATE, sender=dispatcher.Any)
dispatcher.connect(self.handle_created, signal=OP.CREATED, sender=dispatcher.Any)
def handle_extend(self, packet):
if packet.dest != self.id:
return None
iniciopKp=time.time()
print("{}: Handling EXTEND packet from {}".format(self.id, packet.src))
if packet.decrypt_aes(self.__dh_sharedkey):
print("{}: Decryption of EXTEND packet from {} SUCCESS".format(self.id, packet.src))
forward_packet = packet.payload
self.hop_table[1].next = packet.dest
dispatcher.send(signal=forward_packet.op, sender=self, packet=forward_packet)
return
print("{}: Decryption of EXTEND packet from {} FAIL".format(self.id, packet.src))
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
def handle_create(self, packet):
if packet.dest != self.id:
return None
iniciopKp=time.time()
print("{}: Handling CREATE packet from {}".format(self.id, packet.src))
if not packet.decrypt_rsa(self.__privkey):
print("{}: Decryption of CREATE packet from {} FAIL".format(self.id, packet.src))
return
print("{}: Decryption of CREATE packet from {} SUCCESS".format(self.id, packet.src))
other_key = int(packet.payload)
self.dhke.generate_shared_secret(other_key)
self.__dh_sharedkey = self.dhke.shared_key
self.hop_table[1].prev = packet.src
self.send_packet(self.hop_table[1].prev, OP.CREATED)
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
def send_packet(self, receiver, op, payload=None):
iniciopKp=time.time()
packet = self.send_ops[op](receiver, payload)
dispatcher.send(signal=op, sender=self, packet=packet)
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
def get_created_packet(self, receiver, payload=None):
iniciopKp=time.time()
key_hash = hashlib.sha1(
str(self.__dh_sharedkey).encode("utf-8")).hexdigest()
msg = (self.dhke.public_key, key_hash)
packet = Packet(src_id=self.id, op=OP.CREATED,
dest=receiver, payload=(msg, None))
print("{}: Sending CREATED packet to {}".format(self.id, receiver))
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
return packet
def get_extended_packet(self, receiver, payload):
iniciopKp=time.time()
packet = Packet(self.id, OP.EXTENDED, receiver, payload)
print("{}: Sending EXTENDED packet to {}".format(self.id, receiver))
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
return packet
def handle_created(self, packet):
if packet.dest != self.id:
return None
iniciopKp=time.time()
print("{}: Handling CREATE packet from {}".format(self.id, packet.src))
dh_pub_key, key_hash = packet.msg
encrypted_dh_pair = aes_encrypt("{}|||{}".format(dh_pub_key, key_hash), self.__dh_sharedkey)
self.send_packet(self.hop_table[1].prev, OP.EXTENDED, (encrypted_dh_pair, None))
finpKp=time.time()
print('########## Tiempo ##########:',(finpKp-iniciopKp), 'segundos')
def __str__(self):
return self.id
def requestHandler(conn, addr):
'''
This method handles a new download request
'''
# First generate a public-private key pair
dh = DiffieHellman()
dh.generate_public_key()
publicKey = dh.public_key
# Next, send the public key using KEY_EXCHANGE. The segment size is 2479.
conn.sendall(('KEY_EXCHANGE\n' + str(publicKey)).encode('utf-8',
errors='ignore'))
# Receive a similar segment from client. This segment contains the client's public key.
data = receiveData(conn, 2479)
messageType = data.decode('utf-8', errors='ignore').split('\n')[0]
if messageType != 'KEY_EXCHANGE':
print("The client sent an illegal response. Closing connection..")
conn.close()
return
clientPublicKey = int(data.decode('utf-8', errors='ignore').split('\n')[1])
sharedKey = ''
# Generate the shared key using Diffie Hellman algorithm and the public key of client and server
try:
dh.generate_shared_secret(clientPublicKey)
sharedKey = bytes.fromhex(dh.shared_key)
except Exception as e:
print("The client sent an illegal response. Closing connection..")
conn.close()
return
print('Key exchange successful: ' + dh.shared_key)
print('Generating Ciphers..')
# Generate a cipher which will use the shared key to encrypt all outgoing data
cipher = AES.new(sharedKey, AES.MODE_CBC,
'jdirlfhixhtkwlif'.encode('utf-8'))
print('Encrypting File list..')
# Encrypt the file list with the cipher
sharedFilesList = []
for i in sharedFiles:
sharedFilesList.append(i)
fileList = ('\n'.join(sharedFilesList)).encode('utf-8')
encryptedFileList = cipher.encrypt(pad(fileList, AES.block_size))
requiredSize = len(encryptedFileList)
# Send the file list size. We use FILELIST to send the file list size
print('Sending File List..')
conn.sendall(
('FILELIST\n' + padInteger(requiredSize, 20)).encode('utf-8',
errors='ignore'))
# Wait till the server doesn't receive READY signal indicating that the client is ready to take the data
data = receiveData(conn, 5).decode('utf-8', errors='ignore')
if data != 'READY':
print('Client is not ready to receive file list..')
conn.close()
return
# Send the encrypted file list now. The segments contain only body and no header
conn.sendall(encryptedFileList)
# Wait for acknowloedgement
data = receiveData(conn, 3).decode('utf-8', errors='ignore')
if data == 'ACK':
print('File list was received successfully by client..')
else:
print('No Acknowledgement received..')
conn.close()
return
# Wait for a file request
print('Waiting for request..')
data = receiveData(conn, 28).decode('utf-8', errors='ignore').split('\n')
idx = int(data[1])
if data[0] != 'REQUEST':
print('The client sent an illegal response. Closing connection..')
conn.close()
else:
if idx < 0 or idx >= len(sharedFilesList):
print(
'\n\nThe client sent an illegal response. Closing connection..'
)
conn.close()
return
else:
# Open the requested file. Encrypt it with the cipher and send it.
fileName = sharedFilesList[idx].split('/')
fileName = fileName[len(fileName) - 1]
file = open(sharedFilesList[idx], 'rb')
unencryptedData = file.read()
file.close()
cipher = AES.new(sharedKey, AES.MODE_CBC,
'jdirlfhixhtkwlif'.encode('utf-8'))
encryptedData = cipher.encrypt(pad(unencryptedData,
AES.block_size))
requiredPackets = len(encryptedData)
# Send the file size. We use FILE to send the file size
conn.sendall(('FILE\n' + padInteger(requiredPackets, 20)).encode(
'utf-8', errors='ignore'))
# Wait for the ready signal
data = receiveData(conn, 5).decode('utf-8', errors='ignore')
if data != 'READY':
print('Client is not ready to receive the file..')
conn.close()
return
print("Sending the file '" + fileName + "'.")
# Sent the encrypted file
conn.sendall(encryptedData)
print("Sent! Awaiting Acknowledgement..")
# Wait for acknowledgement
data = receiveData(conn, 3).decode('utf-8', errors='ignore')
if data == 'ACK':
print('Client received the file successfully')
conn.close()
else:
print('An unknown error occured in file transfer')
conn.close()
class MessageHandler(asyncore.dispatcher_with_send):
def __init__(self, sock):
asyncore.dispatcher_with_send.__init__(self, sock)
self.name = 0
self.Key = DiffieHellman()
self.Key.generate_public_key()
self.cipher = None
def handle_read(self):
data = self.recv(4096).decode()
print("data: ", data)
if data:
if self.cipher is not None:
j = json.loads(self.cipher.decrypt(data))
else:
j = json.loads(data)
print("loginfo: " + json.dumps(j))
if j["action"] == "register" and self.cipher:
try:
if not j["data"]["login"] in users.keys():
users[j["data"]["login"]] = j["data"]["pass"]
self.name = j["data"]["login"]
clients[self.name] = self
self.send(self.cipher.encrypt(json.dumps({"action": "register", "status": "AUTH_OK"})))
else:
self.send(self.cipher.encrypt(json.dumps({"action": "register", "status": "AUTH_ERR"})))
self.close()
except Exception:
self.send(self.cipher.encrypt(json.dumps({"action": "register", "status": "AUTH_ERR"})))
self.close()
elif j["action"] == "auth" and self.cipher:
try:
if users[j["data"]["login"]] == j["data"]["pass"]:
self.name = j["data"]["login"]
clients[self.name] = self
self.send(self.cipher.encrypt(json.dumps({"action": "auth", "status": "AUTH_OK"})))
else:
self.send(self.cipher.encrypt(json.dumps({"action": "auth", "status": "AUTH_ERR"})))
self.close()
except Exception:
self.send(self.cipher.encrypt(json.dumps({"action": "auth", "status": "AUTH_ERR"})))
self.close()
elif j["action"] == "test":
s = j["data"].encode()
print(s)
elif j["action"] == "message" and self.cipher:
try:
chel = clients[j["data"]["to"]]
chel.send(chel.cipher.encrypt(json.dumps({"action": "message", "data": {"from": self.name, "message": j["data"]["message"]}})))
except Exception:
self.send(self.cipher.encrypt(json.dumps({"action": "message", "status": "MESSAGE_ERR"})))
elif j["action"] == "handshake":
try:
h = SHA.new(int_to_base_str(self.Key.public_key).encode()).digest()
while 1:
k = random.StrongRandom().randint(1, ElGamalObjKey.p-1)
if GCD(k, ElGamalObjKey.p-1) == 1:
break
(SignR, SignS) = ElGamalObjKey.sign(h, k)
self.send(json.dumps({"action": "handshake", "status": "HANDSHAKE_OK", "data": {"pubkey": int_to_base_str(self.Key.public_key), "SignR": SignR, "SignS": SignS}}).encode())
print("pubkey: " + str(base_str_to_int(j["data"]["pubkey"])))
self.Key.generate_shared_secret(base_str_to_int(j["data"]["pubkey"]))
self.cipher = AESCipher(str(self.Key.shared_key).encode())
except Exception as e:
print("ERROR: ", e)
self.send(json.dumps({"action": "handshake", "status": "HANDSHAKE_ERR"}).encode())
else:
print("WATAFA")
class ClientCipher:
def __init__(self, mode, hmac_hash_type):
self.mode = mode
self.hmac_hash_type = hmac_hash_type
# store client app keys
self.client_app_keys = self.generate_keys()
# load server pub. key
self.server_pub_key = serialization.load_pem_public_key(
open(SERVER_PUB_KEY, "rb").read(), backend=default_backend())
# Diffie Hellman
self.client_dh = None
# save session key
self.session_key = None
# warrant nounces
self.warrant_nounces = {}
# how many requests were made to the server
self.request_to_server = 1
def generate_keys(self):
private_key = rsa.generate_private_key(public_exponent=65537,
key_size=2048,
backend=default_backend())
public_key = private_key.public_key()
return private_key, public_key
"""
ASYMMETRIC CIPHER
"""
def asym_cipher(self, pub_key, raw_data):
pickle_dumps = pickle.dumps(raw_data)
return pub_key.encrypt(
pickle_dumps,
_aspaadding.OAEP(mgf=_aspaadding.MGF1(algorithm=hashes.SHA256()),
algorithm=hashes.SHA256(),
label=None))
def asym_decipher(self, private_key, ciphered_data):
data = private_key.decrypt(
ciphered_data,
_aspaadding.OAEP(mgf=_aspaadding.MGF1(algorithm=hashes.SHA256()),
algorithm=hashes.SHA256(),
label=None))
return pickle.loads(data)
def asym_sign(self, private_key, data):
return private_key.sign(
data,
_aspaadding.PSS(mgf=_aspaadding.MGF1(hashes.SHA256()),
salt_length=_aspaadding.PSS.MAX_LENGTH),
hashes.SHA256())
def asym_validate_sign(self, data, sign_data, public_key):
verifier = public_key.verifier(
sign_data,
_aspaadding.PSS(mgf=_aspaadding.MGF1(hashes.SHA256()),
salt_length=_aspaadding.PSS.MAX_LENGTH),
hashes.SHA256())
verifier.update(data)
return verifier.verify()
"""
SYMMETRIC KEY CIPHER
"""
def sym_cipher(self, obj, ks, iv=os.urandom(16), mode=None):
"""
:param iv: key to cipher the object
:param obj: object to be ciphered
:param ks: key to cipher the object
:param mode:
"""
if mode is None:
mode = modes.CTR
cipher = Cipher(algorithms.AES(ks),
mode(iv),
backend=default_backend())
# pickle makes the serialization of the object
pickle_dumps = pickle.dumps(
[obj, os.urandom(RANDOM_ENTROPY_GENERATOR_SIZE)])
# encrypt obj dumped data
encryptor = cipher.encryptor()
ciphered_obj = encryptor.update(pickle_dumps) + encryptor.finalize()
return iv, ciphered_obj
def sym_decipher(self, obj, ks, iv, mode=None):
"""
:param obj:
:param ks:
:param iv:
:param mode:
:return:
"""
if mode is None:
mode = modes.CTR
cipher = Cipher(algorithms.AES(ks),
mode(iv),
backend=default_backend())
decryptor = cipher.decryptor()
deciphered_data = decryptor.update(obj) + decryptor.finalize()
data, random = pickle.loads(deciphered_data)
return data
"""
HYBRID A-SYMMETRIC KEY CIPHER
"""
def hybrid_decipher(self, obj, private_key, ks=None):
obj, random_pickle = pickle.loads(base64.b64decode(obj))
# decipher using rsa private key
if ks is None:
ks = self.asym_decipher(private_key, base64.b64decode(obj["key"]))
# decipher using rsa private key
iv = self.asym_decipher(private_key, base64.b64decode(obj["iv"]))
# decipher using symmetric AES CTR
return self.sym_decipher(base64.b64decode(obj["obj"]), ks, iv)
def hybrid_cipher(self,
obj,
public_key,
ks=os.urandom(32),
cipher_key=True):
# cipher using symmetric cipher AES CTR
# returns the ciphered obj with the IV
iv, ciphered_obj = self.sym_cipher(obj, ks)
# iv ciphered with the public key
iv_encrypted = self.asym_cipher(public_key, iv)
# key ciphered with the public_key
if cipher_key:
# send ks to the server
key_encrypted = self.asym_cipher(public_key, ks)
pickle_dumps = pickle.dumps(
[{
"obj": base64.b64encode(ciphered_obj).decode(),
"iv": base64.b64encode(iv_encrypted).decode(),
"key": base64.b64encode(key_encrypted).decode()
},
os.urandom(RANDOM_ENTROPY_GENERATOR_SIZE)])
return base64.b64encode(pickle_dumps)
else:
pickle_dumps = pickle.dumps(
[{
"obj": base64.b64encode(ciphered_obj).decode(),
"iv": base64.b64encode(iv_encrypted).decode()
},
os.urandom(RANDOM_ENTROPY_GENERATOR_SIZE)])
return base64.b64encode(pickle_dumps)
"""
KEY DERIVATION FUNCTION GIVEN THE MASTER KEY
"""
def key_derivation(self,
masterkey,
salt=os.urandom(32),
iterations=100000):
kdf = PBKDF2HMAC(algorithm=hashes.SHA512(),
length=32,
salt=salt,
iterations=iterations,
backend=default_backend())
return kdf.derive(masterkey), salt
"""
HMAC - create
"""
def hmac_update_finalize(self, key, data):
if not isinstance(key, bytes) and isinstance(key, str):
key = key.encode()
if not isinstance(data, bytes):
data = pickle.dumps(data)
h = hmac.HMAC(key, self.hmac_hash_type(), backend=default_backend())
h.update(data)
return h.finalize()
"""
HMAC - verify
"""
def hmac_verify(self, key, hmac_data, data):
if not isinstance(key, bytes) and isinstance(key, str):
key = key.encode()
if not isinstance(data, bytes):
data = pickle.dumps(data)
h = hmac.HMAC(key, self.hmac_hash_type(), backend=default_backend())
h.update(data)
return h.verify(hmac_data)
"""
SECURE LAYER ENCAPSULATION
"""
def secure_layer_encrypt(self, msg: bytes):
# generate a nounce that will be a warrant of the message
# the nounce will be stored with the respective session key iteration
# after retrieved it will be deleted and then the message exchanged between
# the server and the client will be never deciphered again
nounce = sha256(json.dumps(msg).encode() +
os.urandom(32)).hexdigest().encode()
key, salt = self.key_derivation(self.session_key,
iterations=self.request_to_server)
iv = os.urandom(16)
# saving the iterations ans salt used for the given nounce
self.warrant_nounces[nounce] = {
"iterations": self.request_to_server,
"salt": salt,
"seq": self.request_to_server
}
# salt (the salt used to the KDF), nounce (the genuineness warrant), iv (used in the cipher)
sec_data = pickle.dumps({
"salt": salt,
"nounce": nounce,
"iv": iv,
"seq": self.request_to_server
})
# sec_data ciphered
sec_data_ciphered = self.hybrid_cipher(sec_data, self.server_pub_key)
# HMAC
hmac_key = sha256(key).hexdigest()
hmac_data = self.hmac_update_finalize(hmac_key, msg)
msg = [msg, hmac_data]
pickle_dumps = pickle.dumps(msg)
# cipher with symmetric cipher the message content
iv, ciphered_obj = self.sym_cipher(pickle_dumps,
key,
iv=iv,
mode=self.mode)
# message to be signed and sent to the server
return_message = {
"data": base64.b64encode(ciphered_obj).decode(),
"sec_data": base64.b64encode(sec_data_ciphered).decode()
}
self.request_to_server += 1
# dump the return message
pickle_dumps = pickle.dumps(return_message)
return base64.b64encode(pickle_dumps)
def secure_layer_decrypt(self, msg: bytes):
msg = pickle.loads(base64.b64decode(msg))
# get sec_data content
sec_data = pickle.loads(
self.hybrid_decipher(base64.b64decode(msg["sec_data"]),
self.client_app_keys[0]))
nounce = sec_data["nounce"]
if nounce not in self.warrant_nounces:
print(
"Something went wrong with the nounce in the secure layer decrypt."
)
exit(1)
if sec_data["seq"] != (self.warrant_nounces[nounce]["seq"] + 1):
print("Received wrong sequence number by the server")
exit(1)
# the nounce warrant allow us to retrieve the iterations and the salt used to derive the key
iterations = self.warrant_nounces[nounce]["iterations"]
salt = self.warrant_nounces[nounce]["salt"]
# now it can be deleted
del self.warrant_nounces[nounce]
key, salt = self.key_derivation(self.session_key,
iterations=iterations,
salt=salt)
raw_msg = pickle.loads(
self.sym_decipher(base64.b64decode(msg["data"]),
ks=key,
iv=sec_data["iv"],
mode=self.mode))
# verify hmac
hmac_key = sha256(key).hexdigest()
self.hmac_verify(hmac_key, raw_msg[1], raw_msg[0])
return raw_msg[0]
"""
CLIENT SERVER SESSION KEY NEGOTIATION
"""
def negotiate_session_key(self, phase, val=None):
"""
First the Application loads the server public key that is distributed into the client application.
It's ok to publicly distribute the Public Key but it must be verified if the public key
of the server is still the same. If not, it must be updated. Another way is to request the public key
of the server and ask for the user fingerprint verification. {verification missing}
After that, the client app generate DH values (private and public) to exchange with the server in order to
get the shared secret session key.
Phase 1: [CLIENT]: send generated DH public key to the server (signed) and the app client rsa public key (signed too).
The sent values will be ciphered with a random key and signed.
Phase 2: [SERVER]: the server generates the private and public DH pair. Then using the server private key, the
server decipher the DH public received encrypted value. Using again the server private key, the server deciphers
the client public key and loads it into memory.
Then, using the client public key, validates the signature made for the DH public value and public key received.
Using the received client public key, the server will make a hybrid cipher (AES and RSA) of the DH server
generated public key. After the cipher, the server will sign with the server private key the data ciphered.
Phase 3: [CLIENT]: using the stored server public key the client will validate the signature received. After
that using the client private key, the client will decipher the DH public value received from the server. Then
using the DH public value, the client will generate the DH shared secret and using PBKDF2HMAC will use a key
derivation function. The master key will be the secret DH shared value and will have 100 000 iterations. The
salt is random and so, it will be ciphered and sent to the server.
The session key has been generated.
Phase 4: [SERVER]: Using the client public key it will be verified the signature of the received value. Using
the server private key and a hybrid cipher the PBKDF2 salt will be deciphered. Using the key derivation
function the session key will be obtained in the server.
Then, there is a secure channel between the server and the client.
:param val: value sent by the server
:param phase: 1, 2, 3 or 4
:return: value to send to the server
"""
if phase == 1:
# client generate DH private and public key
self.client_dh = DiffieHellman(key_length=256)
self.client_dh.generate_public_key()
# cipher DH public key with server pub. key
# cipher the client DH public key
client_dh_ciphered = self.hybrid_cipher(self.client_dh.public_key,
self.server_pub_key)
# cipher the client public key
pem = self.client_app_keys[1].public_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PublicFormat.SubjectPublicKeyInfo)
client_public_key_ciphered = self.hybrid_cipher(
pem, self.server_pub_key)
return {
"data":
client_dh_ciphered.decode(),
"data_signature":
base64.b64encode(
self.asym_sign(self.client_app_keys[0],
client_dh_ciphered)).decode(),
"public_key":
client_public_key_ciphered.decode(),
"public_key_signature":
base64.b64encode(
self.asym_sign(self.client_app_keys[0],
client_public_key_ciphered)).decode(),
"phase":
2,
"cipher":
"AES&RSA",
"mode":
self.mode.name,
"hmac_hash":
self.hmac_hash_type.name
}
elif phase == 3:
# validate the DH received value
self.asym_validate_sign(
val["data"].encode(),
base64.b64decode(val["data_signature"].encode()),
self.server_pub_key)
# decipher the received DH value
server_dh_pub = self.hybrid_decipher(val["data"],
self.client_app_keys[0])
# generate shared secret (client session key)
self.client_dh.generate_shared_secret(server_dh_pub)
# save the session key
self.session_key, salt = self.key_derivation(
str(self.client_dh.shared_secret).encode())
salt_ciphered = self.hybrid_cipher(salt, self.server_pub_key)
return {
"phase":
4,
"data":
salt_ciphered.decode(),
"data_signature":
base64.b64encode(
self.asym_sign(self.client_app_keys[0],
salt_ciphered)).decode()
}
class Receiver:
def __init__(self):
self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self._sock_to_mb = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self._sock.bind(ADDRESS)
self._sock.listen(10)
self._df = DiffieHellman()
self._df.generate_private_key()
self._df.generate_public_key()
self._session_key = None
self._k = None
self._k_rand = None
def connection_setup(self):
while True:
# Wait for a connection
connection, address = self._sock.accept()
self._key_exchange(connection, self._df.public_key)
print('My shared key:', self._df.shared_key)
self._derive_from_secret()
print('session key', self._session_key)
try:
self._sock_to_mb.connect(BLINDBOX_ADDRESS)
except socket.error as error:
print(f'Could not connect with blindBox: {error}')
exit(1)
except TypeError as error:
print(f'Type error: {error}')
exit(1)
else:
self._rule_preparation()
def _key_exchange(self, connection, public_key):
"""
After a key exchange using Diffie-Hellman algorithm,
the sender will agree on a shared secret with the receiver.
:param public_key: The sender's public key for key exchange.
:return: None
"""
data = connection.recv(20480)
print(f'data received from the sender: {data}')
try:
pk_from_sender = int(data)
except ValueError:
print('Invalid data type!')
else:
if self._df.verify_public_key(pk_from_sender):
self._df.generate_shared_secret(pk_from_sender)
print('I got the shared key:', self._df.shared_key)
connection.sendall(str(public_key).encode())
else:
raise ValueError('Invalid public key from the sender!')
def _derive_from_secret(self):
"""
Use the shared secret to derive three keys by using a pseudorandom
generator.
_session_key: used to encrypt the traffic in the socket.
_k: used in our detection protocol
_k_rand: used as a seed for randomness. Since both end-points have the same seed,
they will generate the same randomness.
:return: None
"""
key_to_bytes = str(self._df.shared_key).encode()
randoms = Randoms()
self._session_key = derive_key(key_to_bytes, randoms.random1)
self._k = derive_key(key_to_bytes, randoms.random2)
self._k_rand = derive_key(key_to_bytes, randoms.random3)
def _rule_preparation(self):
"""
Sender will use garbled circuits to compute AES(r,k) with the BlindBox while
the sender do not know the rule and the BlindBox do not know the key k.
:return:
"""
key_numbers = int(self._sock_to_mb.recv(1024))
for i in range(key_numbers):
output = subprocess.getoutput(OBLIVC_AES_PATH + "/a.out 5321 -- " +
self._k.decode())
while output == "TCP accept failed":
output = subprocess.getoutput(OBLIVC_AES_PATH +
"/a.out 5321 -- " +
self._k.decode())
def receive(self):
encrypted_traffic = self._sock_to_mb.recv(20480)
encrypted_tokens = self._sock_to_mb.recv(20480)
traffic = aes_decrypt(encrypted_traffic)
self.check_tokens(traffic, encrypted_tokens)
def check_tokens(self, traffic, encrypted_tokens):
pass
if messageType != 'KEY_EXCHANGE':
print("The server sent an illegal response. Closing connection..")
s.close()
exit(0)
serverPublicKey = int(data.decode('utf-8', errors='ignore').split('\n')[1])
# Send the client public key
s.sendall(('KEY_EXCHANGE\n' + str(publicKey)).encode('utf-8', errors='ignore'))
# Generate the shared key using Diffie Hellman algorithm and the public key of client and server
sharedKey = ''
try:
dh.generate_shared_secret(serverPublicKey)
sharedKey = bytes.fromhex(dh.shared_key)
except Exception as e:
print("The server sent an illegal response. Closing connection..")
s.close()
exit(0)
print('Key exchange successful: ' + dh.shared_key)
# Generate a cipher which will use the shared key to decrypt all incoming data
print('Generating Ciphers..')
cipher = AES.new(sharedKey, AES.MODE_CBC, 'jdirlfhixhtkwlif'.encode('utf-8'))
print('Waiting for file list..')
class EncryptionPacket:
PACKET_MAGIC_CODE = struct.pack('>BBBB', 0x43, 0x52, 0x59, 0x54)
FUNCTION_INITIALIZE_HANDSHAKE = 0x00
FUNCTION_SECURE_COMMUNICATION = 0x02
def __init__(self, device, other):
self.device = device
self.other = other
self._user = None
def generate_key(self):
self._user = DiffieHellman()
self._user.generate_public_key()
def send_complete_public_data(self):
data = bytearray(EncryptionPacket.PACKET_MAGIC_CODE) + struct.pack(
">BB", EncryptionPacket.FUNCTION_INITIALIZE_HANDSHAKE, 0x55)
self.other.send(data)
def recv_public_data(self, data):
hash_length = data[0]
hash_value = data[1:hash_length + 1]
hash_str = str()
for i in range(0, len(hash_value)):
hash_str += '{:02x}'.format(int(hex(hash_value[i]), 16))
print("Digest: {}".format(hash_str))
public_key_data = data[hash_length + 1:]
public_key = str()
for i in range(0, len(public_key_data)):
public_key += '{:02X}'.format(int(hex(public_key_data[i]), 16))
m = hashlib.sha256()
m.update(public_key.encode('utf-8'))
other_hash_value = m.hexdigest()
print("Calculated digest: {}".format(other_hash_value))
# the public key is not matched
if hash_str != other_hash_value:
return -1
# Convert str to big-integer
received_public_key = int(public_key)
self._user.generate_shared_secret(received_public_key)
print("Shared key: {}".format(self._user.shared_key))
return 0
def init_encryption_data(self, generated=True, mode=0):
if generated:
self.generate_key()
if self.other is None:
raise ConnectionError("You need to connect the other deivce!")
else:
print("Initializing encryption handshake ...", end='')
key = str(self._user.public_key)
key_array = bytearray()
for i in range(0, len(key), 2):
hex_number = key[i:i + 2]
hex_number = '0x' + str(hex_number)
key_array += struct.pack(">B", int(hex_number, base=16))
print("Generated public key -> len=[{}]".format(len(key_array)))
print("Sending the public key ...")
m = hashlib.sha256()
m.update(key.encode('utf-8'))
result_hash = m.hexdigest()
result_hash_array = bytearray()
for i in range(0, len(result_hash), 2):
hex_number = result_hash[i:i + 2]
hex_number = '0x' + str(hex_number)
result_hash_array += struct.pack(">B", int(hex_number,
base=16))
fih = struct.pack(">B",
EncryptionPacket.FUNCTION_INITIALIZE_HANDSHAKE)
hash_str_length = struct.pack(">B", len(result_hash_array))
self.other.send(EncryptionPacket.PACKET_MAGIC_CODE + fih +
struct.pack(">B", mode) + hash_str_length +
result_hash_array + key_array)
if mode == 0:
print("Awaiting the received public key ...")
class Client:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mujAES = None
cli = None
cislo = 0
def __init__(self, adress):
self.sock.connect((adress, 9876))
if os.path.isfile('User.private.pem') == False or os.path.isfile(
'client1.cert.pem') == False:
createCSR('User', 'heslo', {'CN': 'USER_FQDN'})
self.poslatCertReq()
print("ZADAM SI CERTIFIKAT")
else:
print("NACITAM ZE SLOZKY JAK BOSSs")
self.cert = OpenSSL.crypto.load_certificate(
crypto.FILETYPE_PEM,
open('client1.cert.pem').read())
self.poslatCert()
self.cli = DiffieHellman()
self.cli.generate_public_key()
#presunout do runu
self.vyzadatKlic()
iThread = threading.Thread(target=self.sendMessage)
iThread.daemon = True
iThread.start()
self.run()
def run(self):
while True:
data = self.sock.recv(BUFSIZE)
#misto na hrani si s daty
if not data:
#ukonceni komunikace
break
elif data[0:1] == b"\x66":
with open('client1.cert.pem', 'wb') as cert:
cert.write(data[1:])
self.nastavitCert(data[1:])
#self.cert=OpenSSL.crypto.load_certificate(crypto.FILETYPE_PEM,data[1:])
elif data[0:1] == b"\x11":
#kdyz prijde ridici znak x11-posleme na vyzadani klic
self.poslatKlic()
elif data[0:1] == b"\x98":
createCSR('User', 'heslo', {'CN': 'USER_FQDN'})
self.poslatCertReq()
elif data[0:1] == b"\x12":
#kdyz prijde ridici znak x12 tak si nastavime klic ktery nasleduje po tomto bytu
self.nastavitKlic(data[1:])
elif data[0:1] == b"\x13":
#nezasifrovana komunikace
print(data.decode())
#vynuceni DH pokud prijde nezasifrovana zprava
#self.sock.send(b'\x11')
elif data[0:1] == b"\x14":
#nastaveni klice v pripade ze byl vyzadan nebo tak neco
self.jinenastaveniklice(data[1:])
elif data[0:1] == b'\x20':
self.nastavitCert(data[1:])
else:
#vychozi stav- prijdou data bez ridiciho znaku-> predpokladame ze jsou zasifrovana AESem podle dohodnuteho hesla
data = self.mujAES.decrypt(data)
try:
print("client " + str(self.cislo) + ":" + data.decode())
except:
continue
def vyzadatCert(self):
self.sock.send(b'\x65')
def nastavitCert(self, data):
#self.cert=OpenSSL.crypto.load_certificate_request(crypto.FILETYPE_PEM, data)
self.cert = OpenSSL.crypto.load_certificate(crypto.FILETYPE_PEM, data)
def poslatCert(self):
text = OpenSSL.crypto.dump_certificate(crypto.FILETYPE_PEM, self.cert)
self.sock.send(b'\x33' + text)
def poslatCertReq(self):
#posle certifikat na podepsani¨
with open('User.CSR.pem') as cert:
certificate = OpenSSL.crypto.load_certificate_request(
crypto.FILETYPE_PEM, cert.read())
certext = OpenSSL.crypto.dump_certificate_request(
crypto.FILETYPE_PEM, certificate)
print(certext)
self.sock.send(b'\x15' + certext)
def poslatKlic(self):
#posle ridici znak nasledovany klicem
self.sock.send(b'\x12' + str(self.cli.public_key).encode())
def jinenastaveniklice(self, data):
#dela zajimave veci, ale jen v urcitem pripade
self.cli.generate_shared_secret(int(data.decode()),
echo_return_key=True)
superklic = str(self.cli.shared_secret)
xy = hashlib.sha256(superklic.encode()).hexdigest()[:32]
print("2222222222222222222222222222")
self.cislo = 2
print(xy)
self.mujAES = Encryptor.Encryptor(xy)
def nastavitKlic(self, data):
#nastavuje klic na zaklade dat ktere dostane
self.cli.generate_shared_secret(int(data.decode()),
echo_return_key=True)
superklic = str(self.cli.shared_secret)
xy = hashlib.sha256(superklic.encode()).hexdigest()[:32]
print("111111111111111111111")
self.cislo = 1
print(xy)
self.mujAES = Encryptor.Encryptor(xy)
self.sock.send(b'\x14' + str(self.cli.public_key).encode())
def vyzadatKlic(self):
#nemam klic ale chci, poslu ridici znak
self.sock.send(b'\x11')
def sendMessage(self):
#hlavni chatova smycka
while True:
msg = str(input(""))
if self.mujAES is not None:
msg = self.mujAES.encrypt(msg.encode())
self.sock.send(msg)
else:
msg = msg.encode()
self.sock.send(b'\x13' + msg)
def handle_sock(self, sock, addr): # sock 的流程
##############################
#### Handle a new request#####
#### #####
##############################
while True:
data = sock.recv(4096)
# print ("I have received a new message!")
MessageRec = COMM_MESSAGE()
MessageRec.ParseFromString(data)
if (MessageRec.type == COMM_MESSAGE.TYPE.LOGOUT):
plain_text = self.decryption_with_timestamp_in_client(
MessageRec, self.socket_from_list[src][1],
self.socket_from_list[src][2])
plain_text = plain_text.decode()
print("I received log out request_1")
print(plain_text)
if (plain_text == "log out"):
MessageSend = COMM_MESSAGE()
MessageSend.type = COMM_MESSAGE.TYPE.CONFIRM
plain_text = 'log out confirmed'.encode() + str(
int(time.time())).encode()
MessageSend = self.encryption_in_client(
MessageSend, self.socket_from_list[src][1],
self.socket_from_list[src][2], plain_text)
self.socket_from_list[src][0].sendall(
MessageSend.SerializeToString())
self.socket_from_list[src][0].close()
del self.socket_from_list[src]
del self.user_online[src]
if (MessageRec.type == COMM_MESSAGE.TYPE.CLIENT_TO_CLIENT):
plain_text = self.decryption_of_ticket_with_timestamp(
MessageRec.ticket, MessageRec.ticket_tag)
plain_text = plain_text.decode()
src = plain_text.split(" ")[0]
# self.socket_from_list[src] = []
# self.socket_from_list[src].append (sock)
kab_temp = plain_text.split(" ")[1].encode()
iv_temp = plain_text.split(" ")[2].encode()
plain_text = self.decryption_with_timestamp_in_client(
MessageRec, kab_temp, iv_temp)
plain_text = plain_text.decode()
N1 = int(plain_text)
y = os.urandom(8)
x = y.hex()
N2 = int(x, 16)
plain_text = (str(N1 - 1) + " " + str(N2)).encode() + str(
int(time.time())).encode()
# .encode() + " ".encode + str(N2).encode()
MessageSend = COMM_MESSAGE()
bob = DiffieHellman(group=5, key_length=200)
bob.generate_public_key()
MessageSend.gb_mod_p = str(bob.public_key)
MessageSend = self.encryption_in_client(
MessageSend, kab_temp, iv_temp, plain_text)
sock.sendall(MessageSend.SerializeToString())
MessageRec = COMM_MESSAGE()
data = sock.recv(4096)
MessageRec.ParseFromString(data)
plain_text = self.decryption_with_timestamp_in_client(
MessageRec, kab_temp, iv_temp)
N2_rec = int(plain_text.decode())
if N2 - 1 == N2_rec:
bob.generate_shared_secret(int(MessageRec.message))
kas = str(bob.shared_secret)[:16].encode()
# self.socket_list[src].append(str(bob.shared_secret)[:16].encode())
temp = os.urandom(16)
iv = temp.hex()[:16].encode()
# self.socket_list[src].append(iv)
plain_text = ("Confirm " +
self.client_name).encode() + str(
int(time.time())).encode()
MessageSend = COMM_MESSAGE()
MessageSend.iv = iv
MessageSend = self.encryption_in_client(
MessageSend, kas, iv, plain_text)
sock.sendall(MessageSend.SerializeToString())
MessageRec = COMM_MESSAGE()
data = sock.recv(4096)
MessageRec.ParseFromString(data)
plain_text = self.decryption_with_timestamp_in_client(
MessageRec, kas, iv)
plain_text = plain_text.decode()
if plain_text.split(
" ")[0] == "Confirm" and plain_text.split(
" ")[1] == src:
client_sk = socket.socket()
client_sk.connect(('127.0.0.1', addr[1]))
# print ("I will use this socket to talk to",src,":", client_sk)
self.socket_from_list[src] = []
self.socket_from_list[src].append(client_sk)
self.socket_from_list[src].append(kas)
self.socket_from_list[src].append(iv)
# print("I have succeed in setting up connection with", src, "with session key:", kas)
# print("We use this socket to chatting:", sock)
else:
print("The adversary modify the CONFIRM message")
else:
print("N2 puzzle wrong!")
sys.exit(1)
else:
plain_text = self.decryption_with_timestamp_in_client(
MessageRec, self.socket_from_list[src][1],
self.socket_from_list[src][2])
plain_text = plain_text.decode()
print("From", src, ":", plain_text)
class Client:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mujAES = None
cli = None
def __init__(self, adress='127.0.0.1'):
self.sock.connect((adress, 9876))
self.cli = DiffieHellman()
self.cli.generate_public_key()
self.vyzadatKlic()
iThread = threading.Thread(target=self.sendMessage)
iThread.daemon = True
iThread.start()
self.run()
def run(self):
while True:
data = self.sock.recv(BUFSIZE)
#misto na hrani si s daty
if not data:
#ukonceni komunikace
break
elif data[0:1] == b"\x11":
#kdyz prijde ridici znak x11-posleme na vyzadani klic
self.poslatKlic()
elif data[0:1] == b"\x12":
#kdyz prijde ridici znak x12 tak si nastavime klic ktery nasleduje po tomto bytu
self.nastavitKlic(data[1:])
elif data[0:1] == b"\x13":
#nezasifrovana komunikace
print(data.decode())
elif data[0:1] == b"\x14":
#nastaveni klice v pripade ze byl vyzadan nebo tak neco
self.jinenastaveniklice(data[1:])
else:
#vychozi stav- prijdou data bez ridiciho znaku-> predpokladame ze jsou zasifrovana AESem podle dohodnuteho hesla
data = self.mujAES.decrypt(data)
print(data.decode())
def poslatKlic(self):
#posle ridici znak nasledovany klicem
self.sock.send(b'\x12' + str(self.cli.public_key).encode())
def jinenastaveniklice(self, data):
#dela zajimave veci, ale jen v urcitem pripade
self.cli.generate_shared_secret(int(data.decode()),
echo_return_key=True)
superklic = str(self.cli.shared_secret)
xy = hashlib.sha256(superklic.encode()).hexdigest()[:32]
print("2222222222222222222222222222")
print(xy)
self.mujAES = Encryptor(xy)
def nastavitKlic(self, data):
#nastavuje klic na zaklade dat ktere dostane
self.cli.generate_shared_secret(int(data.decode()),
echo_return_key=True)
superklic = str(self.cli.shared_secret)
xy = hashlib.sha256(superklic.encode()).hexdigest()[:32]
print("111111111111111111111")
print(xy)
self.mujAES = Encryptor(xy)
self.sock.send(b'\x14' + str(self.cli.public_key).encode())
def vyzadatKlic(self):
#nemam klic ale chci, poslu ridici znak
self.sock.send(b'\x11')
def sendMessage(self):
#hlavni chatova smycka
while True:
msg = str(input(""))
if self.mujAES is not None:
msg = self.mujAES.encrypt(msg.encode())
self.sock.send(msg)
else:
msg = msg.encode()
self.sock.send(b'\x13' + msg)
IP_address = '192.168.168.184'
Port = 8202
server.connect((IP_address, Port))
bob = DiffieHellman()
bob.generate_public_key()
x = {"bob":bob.public_key}
server.send(json.dumps(x).encode("utf-8"))
total_data=""
# ########################################## REC #############################################
while True:
try:
message = ""
message = server.recv(100)
while message is not "":
total_data+=message.decode("utf-8")
message = ""
message = server.recv(100)
else:
break
except socket.error as ex:
print(ex)
break
# ########################################## REC #############################################
f= json.loads(total_data)
bob.generate_shared_secret(f["alice"], echo_return_key=True)
print(bob.shared_key)
class ServerCipher:
def __init__(self):
# load server pub. key
self.server_pub_key = serialization.load_pem_public_key(
open(SERVER_PUB_KEY, "rb").read(), backend=default_backend())
# load server priv. key
self.server_priv_key = serialization.load_pem_private_key(
open(SERVER_PRIV_KEY, "rb").read(),
password=None,
backend=default_backend())
# Diffie Hellman
self.server_dh = None
# session key
self.session_key = None
# client public key
self.client_public_key = None
# number of requests received
self.requests_received = 1
# load cc libraries
self.cc = CitizenCard()
# mode CTR, CFB, OFB
self.mode = None
"""
ASYMMETRIC CIPHER
"""
def asym_cipher(self, pub_key, raw_data):
pickle_dumps = pickle.dumps(raw_data)
return pub_key.encrypt(
pickle_dumps,
_aspaadding.OAEP(mgf=_aspaadding.MGF1(algorithm=hashes.SHA256()),
algorithm=hashes.SHA256(),
label=None))
def asym_decipher(self, private_key, ciphered_data):
data = private_key.decrypt(
ciphered_data,
_aspaadding.OAEP(mgf=_aspaadding.MGF1(algorithm=hashes.SHA256()),
algorithm=hashes.SHA256(),
label=None))
return pickle.loads(data)
def asym_sign(self, private_key, data):
return private_key.sign(
data,
_aspaadding.PSS(mgf=_aspaadding.MGF1(hashes.SHA256()),
salt_length=_aspaadding.PSS.MAX_LENGTH),
hashes.SHA256())
def asym_validate_sign(self, data, sign_data, public_key):
verifier = public_key.verifier(
sign_data,
_aspaadding.PSS(mgf=_aspaadding.MGF1(hashes.SHA256()),
salt_length=_aspaadding.PSS.MAX_LENGTH),
hashes.SHA256())
verifier.update(data)
return verifier.verify()
"""
SYMMETRIC KEY CIPHER
"""
def sym_cipher(self, obj, ks, iv=os.urandom(16), mode=None):
"""
:param iv: key to cipher the object
:param obj: object to be ciphered
:param ks: key to cipher the object
"""
if mode is None:
mode = modes.CTR
cipher = Cipher(algorithms.AES(ks),
mode(iv),
backend=default_backend())
# pickle makes the serialization of the object
pickle_dumps = pickle.dumps(
[obj, os.urandom(RANDOM_ENTROPY_GENERATOR_SIZE)])
# encrypt obj dumped data
encryptor = cipher.encryptor()
ciphered_obj = encryptor.update(pickle_dumps) + encryptor.finalize()
return iv, ciphered_obj
def sym_decipher(self, obj, ks, iv, mode=None):
"""
:param obj:
:param ks:
:param iv:
:return:
"""
if mode is None:
mode = modes.CTR
cipher = Cipher(algorithms.AES(ks),
mode(iv),
backend=default_backend())
decryptor = cipher.decryptor()
deciphered_data = decryptor.update(obj) + decryptor.finalize()
data, random = pickle.loads(deciphered_data)
return data
"""
HYBRID A-SYMMETRIC KEY CIPHER
"""
def hybrid_decipher(self, obj, private_key, ks=None):
obj, random_pickle = pickle.loads(base64.b64decode(obj))
# decipher using rsa private key
if ks is None:
ks = self.asym_decipher(private_key, base64.b64decode(obj["key"]))
# decipher using rsa private key
iv = self.asym_decipher(private_key, base64.b64decode(obj["iv"]))
# decipher using symmetric AES CTR
return self.sym_decipher(base64.b64decode(obj["obj"]), ks, iv)
def hybrid_cipher(self,
obj,
public_key,
ks=os.urandom(32),
cipher_key=True):
# cipher using symmetric cipher AES CTR
# returns the ciphered obj with the IV
iv, ciphered_obj = self.sym_cipher(obj, ks)
# iv ciphered with the public key
iv_encrypted = self.asym_cipher(public_key, iv)
# key ciphered with the public_key
if cipher_key:
# send ks to the server
key_encrypted = self.asym_cipher(public_key, ks)
pickle_dumps = pickle.dumps(
[{
"obj": base64.b64encode(ciphered_obj).decode(),
"iv": base64.b64encode(iv_encrypted).decode(),
"key": base64.b64encode(key_encrypted).decode()
},
os.urandom(RANDOM_ENTROPY_GENERATOR_SIZE)])
return base64.b64encode(pickle_dumps)
else:
pickle_dumps = pickle.dumps(
[{
"obj": base64.b64encode(ciphered_obj).decode(),
"iv": base64.b64encode(iv_encrypted).decode()
},
os.urandom(RANDOM_ENTROPY_GENERATOR_SIZE)])
return base64.b64encode(pickle_dumps)
"""
KEY DERIVATION FUNCTION GIVEN THE MASTER KEY
"""
def key_derivation(self,
masterkey,
salt=os.urandom(32),
iterations=100000):
kdf = PBKDF2HMAC(algorithm=hashes.SHA512(),
length=32,
salt=salt,
iterations=iterations,
backend=default_backend())
return kdf.derive(masterkey), salt
"""
HMAC - create
"""
def hmac_update_finalize(self, key, data):
if not isinstance(key, bytes):
key = key.encode()
if not isinstance(data, bytes):
data = pickle.dumps(data)
h = hmac.HMAC(key, self.hmac_hash(), backend=default_backend())
h.update(data)
return h.finalize()
"""
HMAC - verify
"""
def hmac_verify(self, key, hmac_data, data):
if not isinstance(key, bytes):
key = key.encode()
if not isinstance(data, bytes):
data = pickle.dumps(data)
h = hmac.HMAC(key, self.hmac_hash(), backend=default_backend())
h.update(data)
return h.verify(hmac_data)
"""
SECURE LAYER ENCAPSULATION
"""
def secure_layer_encrypt(self, msg: bytes, sec_data: dict):
# the nounce has been already generated by the client
# the iterations number will be the number of requests received by the server for that client
# the number that counts is the decrypt number
key, salt = self.key_derivation(masterkey=self.session_key,
salt=sec_data["salt"],
iterations=sec_data["iterations"])
# HMAC
hmac_key = sha256(key).hexdigest()
hmac_data = self.hmac_update_finalize(hmac_key, msg)
pickle_dumps = pickle.dumps([msg, hmac_data])
iv, ciphered_msg = self.sym_cipher(pickle_dumps,
ks=key,
mode=self.mode)
sec_data = pickle.dumps({
"nounce": sec_data["nounce"],
"seq": sec_data["seq"],
"iv": iv
})
# sec_data ciphered
sec_data_ciphered = self.hybrid_cipher(sec_data,
self.client_public_key)
return_message = {
"data": base64.b64encode(ciphered_msg).decode(),
"sec_data": base64.b64encode(sec_data_ciphered).decode()
}
# dump the return message
pickle_dumps = pickle.dumps(return_message)
return base64.b64encode(pickle_dumps)
def secure_layer_decrypt(self, msg: bytes):
msg = pickle.loads(base64.b64decode(msg))
data = msg["data"].encode()
sec_data = base64.b64decode(msg["sec_data"])
iterations = self.requests_received
self.requests_received += 1
# decipher the sec_data
sec_data = pickle.loads(
self.hybrid_decipher(sec_data, self.server_priv_key))
salt = sec_data["salt"]
nounce = sec_data["nounce"]
iv = sec_data["iv"]
key, salt = self.key_derivation(self.session_key,
iterations=iterations,
salt=salt)
raw_msg = pickle.loads(
self.sym_decipher(base64.b64decode(data), key, iv, self.mode))
# verify hmac
hmac_key = sha256(key).hexdigest()
self.hmac_verify(hmac_key, raw_msg[1], raw_msg[0])
data = {
"nounce": nounce,
"salt": salt,
"iterations": iterations,
"seq": sec_data["seq"] + 1
}
return raw_msg[0], data
"""
CLIENT SERVER SESSION KEY NEGOTIATION
"""
def negotiate_session_key(self, phase, val=None):
"""
First the Application loads the server public key that is distributed into the client application.
It's ok to publicly distribute the Public Key but it must be verified if the public key
of the server is still the same. If not, it must be updated. Another way is to request the public key
of the server and ask for the user fingerprint verification. {verification missing}
After that, the client app generate DH values (private and public) to exchange with the server in order to
get the shared secret session key.
Phase 1: [CLIENT]: send generated DH public key to the server (signed) and the app client rsa public key (signed too).
The sent values will be ciphered with a random key and signed.
Phase 2: [SERVER]: the server generates the private and public DH pair. Then using the server private key, the
server decipher the DH public received encrypted value. Using again the server private key, the server deciphers
the client public key and loads it into memory.
Then, using the client public key, validates the signature made for the DH public value and public key received.
Using the received client public key, the server will make a hybrid cipher (AES and RSA) of the DH server
generated values. After the cipher, the server will sign with the server private key the data ciphered.
Phase 3: [CLIENT]: using the stored server public key the client will validate the signature received. After
that using the client private key, the client will decipher the DH public value received from the server. Then
using the DH public value, the client will generate the DH shared secret and using PBKDF2HMAC will use a key
derivation function. The master key will be the secret DH shared value and will have 100 000 iterations. The
salt is random and so, it will be ciphered and sent to the server.
The session key has been generated.
Phase 4: [SERVER]: Using the client public key it will be verified the signature of the received value. Using
the server private key and a hybrid cipher the PBKDF2 salt will be deciphered. Using the key derivation
function the session key will be retrieved in the server.
Then, there is a secure channel between the server and the client.
:param phase: negotiation phase
:param val: value sent by the client
:return: value to send to the client
"""
if phase == 2:
# server generate DH private and public key, 1024 para cima ou curva elipticas
self.server_dh = DiffieHellman(key_length=256)
self.server_dh.generate_public_key()
# get mode
if val["mode"] == "CTR":
self.mode = modes.CTR
elif val["mode"] == "CFB":
self.mode = modes.CFB
elif val["mode"] == "OFB":
self.mode = modes.OFB
else:
print("Wrong input!")
exit(1)
if val["hmac_hash"] == "sha256":
self.hmac_hash = hashes.SHA256
elif val["hmac_hash"] == "sha512":
self.hmac_hash = hashes.SHA512
# decipher the received DH value
client_dh_pub = self.hybrid_decipher(val["data"],
self.server_priv_key)
# decipher client public key PEM format
client_public_key_pem = self.hybrid_decipher(
val["public_key"], self.server_priv_key)
# load the client public key
self.client_public_key = serialization.load_pem_public_key(
client_public_key_pem, backend=default_backend())
# validate signed data [data = dh value]
self.asym_validate_sign(
val["data"].encode(),
base64.b64decode(val["data_signature"].encode()),
self.client_public_key)
# validate signature of client public key
self.asym_validate_sign(
val["public_key"].encode(),
base64.b64decode(val["public_key_signature"].encode()),
self.client_public_key)
# cipher the server DH public key with the client public key
server_dh_ciphered = self.hybrid_cipher(self.server_dh.public_key,
self.client_public_key)
# generate the DH shared secret (client session key)
self.server_dh.generate_shared_secret(client_dh_pub)
return {
"data":
server_dh_ciphered.decode(),
"data_signature":
base64.b64encode(
self.asym_sign(self.server_priv_key,
server_dh_ciphered)).decode(),
"phase":
3
}
elif phase == 4:
# validate signature of the received salt
self.asym_validate_sign(
val["data"].encode(),
base64.b64decode(val["data_signature"].encode()),
self.client_public_key)
# decipher the salt for PBKDF2
pbkdf2_salt = self.hybrid_decipher(val["data"],
self.server_priv_key)
# save the session key
self.session_key, salt = self.key_derivation(
str(self.server_dh.shared_secret).encode(), pbkdf2_salt)