def find_value_from_hash(msg):
for i in range(10000, 99999):
value = util.get_hash(i)
if (value == msg):
return i
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()
