def receiveThread():
global authenticated, user
while True:
msge = receive(client_socket, raw=True)
try:
msg = msge.decode('utf8')
except:
msg = ""
if (checkCMD('!login success', msg)
or checkCMD('!signup success', msg)):
action = "login" if checkCMD('!login success', msg) else "signup"
infodump = receive(client_socket, raw=True)
info = pickle.loads(infodump)
if (action == "login"):
with open("./data/" + info["id"], 'rb') as userfile:
user = pickle.load(userfile)
else:
user = User(info['id'], info['p'], info['g'])
with open("./data/" + user.id, 'wb+') as userfile:
pickle.dump(user, userfile)
send(str(user.publicKey), client_socket)
elif checkCMD("!new user", msg):
send("!new user", client_socket)
display("Adding user, please wait...")
while (True):
try:
publicKeys = pickle.loads(receive(client_socket, raw=True))
if (user.id not in publicKeys):
publicKeys[user.id] = user.publicKey
keyExchange(user, publicKeys)
send(pickle.dumps(user.encryptedSenderKeys),
client_socket,
raw=True)
tmp = receive(client_socket, raw=True)
otherSenderKeys = pickle.loads(tmp)
user.decryptSenderKeys(otherSenderKeys)
with open("./data/" + user.id, 'wb+') as userfile:
pickle.dump(user, userfile)
authenticated = True
break
except:
display("Waiting for server, please wait...")
time.sleep(0.5)
elif checkCMD('!quit', msg):
user.encryptSenderKeys()
with open("./data/" + user.id, 'wb+') as userfile:
pickle.dump(user, userfile)
display("Terminating connection")
client_socket.close()
os._exit(1)
elif checkCMD('!broadcast', msg):
display(msg[len("!broadcast"):])
else:
if (authenticated):
fromUser = msge[:USERNAME_LENGTH].decode('utf8').strip()
nonceRec, msgRec, tagRec = pickle.loads(msge[USERNAME_LENGTH:])
if fromUser == user.id:
decipher = AES.new(user.senderKey,
AES.MODE_EAX,
nonce=nonceRec)
else:
decipher = AES.new(user.decryptedSenderKeys[fromUser],
AES.MODE_EAX,
nonce=nonceRec)
decMsgRec = decipher.decrypt(msgRec)
try:
decipher.verify(tagRec)
except ValueError:
display(
"MAC verification failed. Message may have been tampered with or ratcheting got out of sync"
)
if (fromUser != user.id):
display(fromUser + ": " + decMsgRec.decode('utf8'))
user.decryptedSenderKeys[fromUser] = KDF(
user.decryptedSenderKeys[fromUser], RATCHETING_STEPS)
else:
display(fromUser + ": " + decMsgRec.decode('utf8'))
user.senderKey = KDF(user.senderKey, RATCHETING_STEPS)
else:
display(msg)
