def receiveMessages(sock, username, sip, sport, A, password, a):
while(1):
try:
# try to receive messages from the server
msg = sock.recv(40960) # changed here akshay
if msg != '':
msg1 = pickle.loads(msg)
#print("Received message:%s" %(msg1))
status = progress[username]
if(status == 1):
if(msg1 == 'ERROR'):
global EXIT_IN_ERROR
EXIT_IN_ERROR = True
sys.exit()
value = find_value_from_hash(msg1)
send_message(sock, value, sip, sport)
progress[username] = 2
if(status == 2):
challenge_pk_data = {}
data_for_kas = {}
final_to_server = {}
global shared_key
shared_key = compute_shared_key(A, msg1, username, password, a)
final_kas = util.MD5_HASH(shared_key)
challenge = util.get_random_number()
global NONCE_SENT
NONCE_SENT = challenge
data_for_kas.update({'CHALLENGE': challenge , 'PK_CLIENT': CLIENT_PUBLIC_KEY_STR})
Kas_encrypted_data = util.encrypt_message_KAS(data_for_kas, final_kas, GENERATED_IV)
# add IV here
challenge_pk_data.update({'CHALLENGE_PK': Kas_encrypted_data, 'CHALLENGE': challenge, 'IV': GENERATED_IV})
data_to_server = util.encrypt_message_PSK(challenge_pk_data, SERVER_KEY)
send_message(sock, data_to_server, sip, sport)
progress[username] = 3
if(status == 3):
hash_shared_key = util.MD5_HASH(shared_key)
nonce = util.decrypt_using_Kas(msg1, hash_shared_key, GENERATED_IV)
incremented_nonce = long(nonce) + 1
if incremented_nonce == NONCE_SENT:
print ("Login Success !")
return True
else:
print("Authentication pending!")
return False
else:
print("Connection with server is broken...")
sys.exit()
except KeyboardInterrupt:
sock.close()
# handling socket errors
except socket.error, s_error:
sock.close()
error_code = s_error[0]
error_message = s_error[1]
print('Error in reading messages: ', error_code, ' - ', error_message)
except Exception as e:
print('Error occured:', e)
sock.close()
sys.exit()
def non_blocking_listen(server, current_username):
global USERNAME_TO_PORT
global CHAT_NONCE
global shared_key
global g
global p
global a
global df_keys
global message_tracker
global IV_tracker
global df_progress
global port_tracker
udp_socket = create_udp_socket()
udp_socket.bind(server.getsockname())
read_sockets = [server, sys.stdin, udp_socket]
write_sockets = []
message_queue = {}
timeout = 30
try:
while(read_sockets):
#print("Waiting for read/write event...")
readable, writable, exceptional = select.select(read_sockets, write_sockets, read_sockets, timeout)
for s in readable:
if s == sys.stdin:
command = s.readline().strip()
if command.lower() == 'list' or command.lower() == 'logout':
global ACTION_NONCE
ACTION_NONCE = util.get_random_number()
message = {}
message.update({'ACTION': command.upper()})
message.update({'username': current_username})
message.update({'NONCE': ACTION_NONCE})
try:
final_kas = util.MD5_HASH(shared_key)
to_send = util.encrypt_message_KAS(message, final_kas, GENERATED_IV)
except Exception as e:
print "An error occured while encrypting the text message for ACTION. ", message, "! %s" %e
send_message(server, to_send, sip, sport)
# you are A
if command.split(" ")[0] == "send":
chat_text = command.split(" ")[1:]
sender_username = chat_text[0]
message_tracker[sender_username] = ' '.join(chat_text)
#udp_socket.sendto(' '.join(chat_text[1:]),('localhost',int(USERNAME_TO_PORT[sender_username])))
# update
CHAT_NONCE = util.get_random_number()
message = {}
message.update({'ACTION': 'CHAT'})
message.update({'A': current_username})
message.update({'B': sender_username})
message.update({'NONCE': CHAT_NONCE})
try:
final_kas = util.MD5_HASH(shared_key)
to_send = util.encrypt_message_KAS(message, final_kas, GENERATED_IV)
except Exception as e:
print "An error occured while encrypting the text message for ACTION. ", message, "! %s" %e
send_message(server, to_send, sip, sport)
# update ends
if s is server and s != sys.stdin:
data = s.recv(40960)
if data:
pickled_data = pickle.loads(data)
#print("Received data - %s from %s" %(pickled_data, s.getpeername()))
hash_shared_key = util.MD5_HASH(shared_key)
response = util.decrypt_using_Kas(pickled_data, hash_shared_key, GENERATED_IV)
d = ast.literal_eval(response)
valid = False
if(str(d['ACTION']).strip() == 'LIST'):
list_message = d['MESSAGE']
list_of_users = []
if type(list_message) == str:
print list_message
else:
print "~~~~~~~~~~~~~ Online Users ~~~~~~~~~~~~~"
for item in list_message:
username = item[0]
portip = item[1]
port = portip.split(":")[1]
USERNAME_TO_PORT.update({username:int(port)})
print username
print "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"
valid = True
if(str(d['ACTION']).strip() == 'LOGOUT'):
received_nonce = d['MESSAGE']
if(long(received_nonce) + 1 == ACTION_NONCE):
print "Confirming logout"
valid = True
if valid:
challenge_nonce = d['NONCE']
decrement_nonce = long(challenge_nonce) - 1
try:
final_kas = util.MD5_HASH(shared_key)
to_send = util.encrypt_message_KAS(decrement_nonce, final_kas, GENERATED_IV)
except Exception as e:
print "An error occured while encrypting the text message for ACTION. ", message, "! %s" %e
send_message(server, to_send, sip, sport)
if(str(d['ACTION']).strip() == 'LOGOUT'):
server.close()
for s in read_sockets:
if s != sys.stdin:
s.close()
for s in write_sockets:
s.close()
#sys.exit()
#message_queue[s].put(pickled_data)
# update starts
# you are A
if(str(d['ACTION']).strip() == 'CHAT'):
ticket = d['TICKET']
b_port = d['B_PORT']
b_ip = d['B_IP']
b_pk = d['B_PK']
b_iv = d['B_IV']
b = d['B']
IV_tracker[b] = b_iv
port_tracker[b] = int(b_port)
nonce = d['NONCE']
new_challenge = d['CHALLENGE']
if(long(nonce) + 1 == long(CHAT_NONCE)):
message = {}
message.update({'TICKET': ticket})
message.update({'NONCE': new_challenge})
a = random.randint(1, 9)
A = (g**a) % p
message.update({'A': A})
message.update({'g': g})
message.update({'p': p})
try:
msg = util.encrypt_with_PSK(message, b_pk)
#pickled_msg = pickle.dumps(msg)
except Exception as e:
print "An error occured while encrypting the text message - ", message, "! %s" %e
protocol_identity = {}
protocol_identity.update({'CIPHER': msg})
protocol_identity.update({'PROTOCOL': 'PUBLIC_KEY'})
pickled_msg = pickle.dumps(protocol_identity)
udp_socket.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 18000)
udp_socket.sendto(pickled_msg,('localhost',int(b_port)))
# update ends
else:
print("Connection closed")
if s in write_sockets:
write_sockets.remove(s)
read_sockets.remove(s)
close_socket(s)
del message_queue[s]
elif s == udp_socket:
# update begins
msg = s.recvfrom(30000)
if msg:
pickled_data = pickle.loads(msg[0])
protocol = pickled_data['PROTOCOL']
cipher = pickled_data['CIPHER']
if(protocol == 'PUBLIC_KEY'):
# You are user B
cipher2, e_iv , e_sym_key = extract_cipher_data(cipher)
decrypted_data = decrypt(cipher2, e_iv, e_sym_key)
if(decrypted_data.has_key('A')):
A = long(decrypted_data['A'])
g = long(decrypted_data['g'])
p = long(decrypted_data['p'])
ticket = decrypted_data['TICKET']
nonce = decrypted_data['NONCE']
b = random.randint(100, 999)
B = (g**b) % p
b_shared_key = (A**b) % p
hash_shared_key = util.MD5_HASH(shared_key)
response = util.decrypt_using_Kas(ticket, hash_shared_key, GENERATED_IV)
d = ast.literal_eval(response)
message = {}
message.update({'B': B})
# B's username
message.update({'username': current_username})
a_pk = d['A_PK']
a_ip = d['A_IP']
a_port = d['A_PORT']
# A's username
username = d['A']
ticket_nonce = d['NONCE']
if long(nonce) == long(ticket_nonce):
df_keys[username] = str(b_shared_key)
df_progress[current_username] = (2, username)
try:
msg = util.encrypt_with_PSK(message, a_pk)
#pickled_msg = pickle.dumps(msg)
except Exception as e:
print "An error occured while encrypting the text message - ", message, "! %s" %e
protocol_identity = {}
protocol_identity.update({'PROTOCOL': 'PUBLIC_KEY'})
protocol_identity.update({'CIPHER': msg})
pickled_msg = pickle.dumps(protocol_identity)
#udp_socket.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 20000)
udp_socket.sendto(pickled_msg,('localhost',int(a_port)))
else:
# you are user A
if(decrypted_data.has_key('B')):
B = long(decrypted_data['B'])
# B's username
username = decrypted_data['username']
ds_shared_key = (B ** a) % p
df_keys[username] = str(ds_shared_key)
B_IV = IV_tracker[username]
B_port = port_tracker[username]
message_to_send = message_tracker[username]
hmac_msg = util.get_hmac(message_to_send, B_IV)
to_send_dict = {}
to_send_dict.update({'MESSAGE': message_to_send})
to_send_dict.update({'HMAC': hmac_msg})
try:
final_kas = util.MD5_HASH(df_keys[username])
to_send = util.encrypt_message_KAS(to_send_dict, final_kas, B_IV)
except Exception as e:
print "An error occured while encrypting the text message for CHAT. ", message, "! %s" %e
protocol_identity = {}
protocol_identity.update({'PROTOCOL': 'SESSION_KEY'})
protocol_identity.update({'CIPHER': to_send})
pickled_msg = pickle.dumps(protocol_identity)
udp_socket.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 20000)
udp_socket.sendto(pickled_msg,('localhost',int(B_port)))
if(protocol == 'SESSION_KEY'):
# you are user B
progress_tuple = df_progress[current_username]
if (progress_tuple[0] == 2):
b_username = progress_tuple[1]
hash_shared_key = util.MD5_HASH(str(df_keys[b_username]))
response = util.decrypt_using_Kas(cipher, hash_shared_key, GENERATED_IV)
d = ast.literal_eval(response)
msg_received = d['MESSAGE']
msg_hmac = d['HMAC']
util.verify_with_hmac(msg_received, msg_hmac, GENERATED_IV)
print msg_received
del df_progress[current_username]
# update ends
for s in writable:
try:
next_msg = message_queue[s].get_nowait()
to_send = pickle.dumps(next_msg)
except Queue.Empty:
print("Queue Empty")
write_sockets.remove(s)
else:
print("Sending message - %s to %s" %(to_send, s.getpeername()))
s.send(to_send)
for s in exceptional:
print("Exceptional condition occurred for user - %s" %(s.getpeername()))
read_sockets.remove(s)
if s in write_sockets:
write_sockets.remove(s)
close_socket(s)
del message_queue[s]
except KeyboardInterrupt:
"Inside KeyboardInterrupt!!!!!!!!"
server.close()
for s in read_sockets:
if s != sys.stdin:
s.close()
for s in write_sockets:
s.close()
sys.exit()
except:
print 'Closing client .....'
server.close()
for s in read_sockets:
if s != sys.stdin:
s.close()
for s in write_sockets:
s.close()
sys.exit()
def non_blocking_listen(server):
server.listen(5)
read_sockets = [server]
write_sockets = []
message_queue = {}
timeout = 30
load_client_vault()
try:
while(read_sockets):
readable, writable, exceptional = select.select(read_sockets, write_sockets, read_sockets, timeout)
for s in readable:
if s is server:
conn, client_address = s.accept()
print("Received connection - %s from %s" %(conn, client_address))
conn.setblocking(0)
read_sockets.append(conn)
message_queue[conn] = Queue.Queue()
client_progress[conn] = (1,)
else:
data = s.recv(40960)
if data:
pickled_data = pickle.loads(data)
status = client_progress[s]
if(status[0] == 1):
#A, username = parse_data(pickled_data)
cipher, e_iv , e_sym_key = extract_cipher_data(pickled_data)
decrypted_data = decrypt(cipher, e_iv, e_sym_key)
A = str(decrypted_data["A"])
username = str(decrypted_data["username"])
if(not logged_users.has_key(username)):
num = util.get_random_challenge()
hashed_num = util.get_hash(num)
message_queue[s].put(hashed_num)
# num is added so u can check in the next step that value sent by client is same as num
client_progress[s] = (2, A, username, num)
else:
print 'User: %s is already logged in!' %(username)
message_queue[s].put('ERROR')
if(status[0] == 2):
salt = util.get_random_number() #Salt
user_tuple = client_progress[s]
username = user_tuple[2]
numCheck = user_tuple[3]
if user_tuple[1] and user_tuple[2] and pickled_data == numCheck:
salt_and_B_dict = {}
A = user_tuple[1]
B, v, b = get_params(user_tuple[2], user_tuple[1], salt)
u = util.H(A,B)
signed_salt = util.sign_document(private_key, str(salt).encode())
signed_B = util.sign_document(private_key, str(B).encode())
salt_and_B_dict.update({'SALT': salt})
salt_and_B_dict.update({'SIGNED_SALT': signed_salt})
salt_and_B_dict.update({'B': B})
salt_and_B_dict.update({'SIGNED_B': signed_B})
message_queue[s].put(salt_and_B_dict)
Kas = util.get_server_shared_key(A, v, u, b)
client_progress[s] = (3, util.MD5_HASH(Kas), username)
if(status[0] == 3):
user_tuple = client_progress[s]
cipher, e_iv , e_sym_key = extract_cipher_data(pickled_data)
decrypted_data = decrypt(cipher, e_iv, e_sym_key)
Challenge_PK = decrypted_data['CHALLENGE_PK']
IV = decrypted_data['IV']
final_decrypted_data = util.decrypt_using_Kas(Challenge_PK, user_tuple[1], IV)
d= ast.literal_eval(final_decrypted_data)
if str(d['CHALLENGE']) == str(decrypted_data['CHALLENGE']):
print 'Challenge matches'
#global logged_users
client_ip = s.getpeername()[0]
client_port = s.getpeername()[1]
ip_port = str(client_ip) + ":" + str(client_port)
logged_users[username] = (user_tuple[1], s, d['PK_CLIENT'],ip_port, IV) # .................
else:
print 'Challenge does not match'
nonce = d['CHALLENGE']
subtracted_nonce = long(nonce) - 1
#iv = os.urandom(16)
encrypted_nonce = util.encrypt_message_KAS(str(subtracted_nonce), user_tuple[1], IV)
message_queue[s].put(encrypted_nonce)
client_progress[s] = (4, util.MD5_HASH(Kas), username, IV)
if(status[0] == 4):
user_tuple = client_progress[s]
IV = user_tuple[3]
final_decrypted_data = util.decrypt_using_Kas(pickled_data, user_tuple[1], IV)
d= ast.literal_eval(final_decrypted_data)
if(type(d) != long):
valid = False
if(action_progress.has_key(s)):
action_status = action_progress[s]
status_2 = action_status[1]
valid = (status_2 == 3)
else:
valid = True
if (valid):
if(d['ACTION'] == 'LIST'):
A_ip_port = ''
all_users = []
for username, value in logged_users.items():
if not username == d['username']:
A_ip_port = value[3]
all_users.append((username, A_ip_port))
if len(all_users) == 0:
all_users = 'No user is online currently'
action_challenge = util.get_random_number()
user_list = {}
user_list.update({'MESSAGE': all_users})
user_list.update({'NONCE': action_challenge})
user_list.update({'ACTION': 'LIST'})
final_kas = user_tuple[1]
try:
to_send = util.encrypt_message_KAS(user_list, final_kas, IV)
except:
print "An error occured while encrypting the text message for ACTION. ", message, "! %s" %e
message_queue[s].put(to_send)
action_progress[s] = ('LIST', 2, action_challenge)
if(d['ACTION'] == 'LOGOUT'):
user_to_remove = d['username']
challenge_received = d['NONCE']
decrement_nonce = long(challenge_received) - 1
new_nonce = util.get_random_number()
user_list = {}
user_list.update({'MESSAGE': decrement_nonce})
user_list.update({'NONCE': new_nonce})
user_list.update({'ACTION': 'LOGOUT'})
final_kas = user_tuple[1]
try:
to_send = util.encrypt_message_KAS(user_list, final_kas, IV)
except:
print "An error occured while encrypting the text message for ACTION. ", message, "! %s" %e
message_queue[s].put(to_send)
action_progress[s] = ('LOGOUT', 2, new_nonce)
# UPDATE START
if(d['ACTION'] == 'CHAT'):
A_ipport = ''
B_ipport = ''
A_PK = ''
B_PK = ''
Kbs = ''
Kas = ''
for username, value in logged_users.items():
if username == d['A']:
A_ipport = value[3]
Kas = value[0]
A_PK = str(value[2])
if username == d['B']:
B_ipport = value[3]
Kbs = value[0]
B_PK = value[2]
A_IP = A_ipport.split(":")[0]
A_PORT = A_ipport.split(":")[1]
username_A = d['A']
N6 = util.get_random_number()
TICKET = {}
ticket_and_stuff = {}
TICKET.update({'A_PORT':A_PORT})
TICKET.update({'A_IP':A_IP})
TICKET.update({'A_PK':A_PK})
TICKET.update({'A':username_A})
TICKET.update({'NONCE':N6})
final_kas = user_tuple[1]
username_B = str(d['B'])
# use B's IV
login_tuple = logged_users[username_B]
B_IV = login_tuple[4]
Kbs_encrypted_ticket = util.encrypt_message_KAS(TICKET, Kbs, B_IV)
N4 = d['NONCE']
B_IP = B_ipport.split(":")[0]
B_PORT = B_ipport.split(":")[1]
N4_minus_1 = long(N4) - 1
ticket_and_stuff.update({'TICKET':Kbs_encrypted_ticket})
ticket_and_stuff.update({'B_PORT':B_PORT})
ticket_and_stuff.update({'B_IP':B_IP})
ticket_and_stuff.update({'B_PK':B_PK})
ticket_and_stuff.update({'NONCE':N4_minus_1})
ticket_and_stuff.update({'CHALLENGE':N6})
ticket_and_stuff.update({'ACTION':'CHAT'})
ticket_and_stuff.update({'B_IV': B_IV})
ticket_and_stuff.update({'B': username_B})
Kas_final_encrypt = util.encrypt_message_KAS(ticket_and_stuff, Kas, IV)
message_queue[s].put(Kas_final_encrypt)
#UPDATE END
else:
action_status = action_progress[s]
if(action_status[1] == 2 and action_status[0] == 'LIST'):
action_progress[s] = (action_status[0], 3)
if(action_status[1] == 2 and action_status[0] == 'LOGOUT'):
earlier_nonce = action_status[2]
if(long(final_decrypted_data) == long(earlier_nonce) - 1):
print ' deleting user info '
del logged_users[user_to_remove]
print 'Deleting user: '******' Did not receive logout confirmation '
else:
print 'Message ignored'
#message_queue[s].put(pickled_data)
if s not in write_sockets:
write_sockets.append(s)
else:
if (client_progress.has_key(s)):
client_status = client_progress[s]
if(client_status[0] > 1):
print("Connection closed ...... !")
del logged_users[client_status[2]]
print 'Deleting user: '******'Closing server .....'
server.close()
for s in read_sockets:
s.close()
for s in write_sockets:
s.close()
