BiztProtoBois/client
BiztProtoBois/client
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use authenticated chacha20

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This commit is contained in:
Torma Kristóf 2021-04-26 16:58:16 +02:00
parent f8b947690b
commit 862c1f17af
Signed by: tormakris
GPG Key ID: DC83C4F2C41B1047
1 changed files with 27 additions and 19 deletions
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46
client/netwrapper.py
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@ -5,7 +5,7 @@ import json
from base64 import b64encode, b64decode
import pyDH
from Crypto.Hash import SHA512
from Crypto.Cipher import ChaCha20, PKCS1_OAEP
from Crypto.Cipher import ChaCha20_Poly1305, PKCS1_OAEP
from Crypto.PublicKey.RSA import RsaKey
from Crypto.Random import get_random_bytes
@ -66,11 +66,14 @@ class NetWrapper:
def authenticate(self, password: str):
message = f"LIN {self.username} {password}".encode('UTF-8')
cipher = ChaCha20.new(key=self.cipherkey, nonce=get_random_bytes(12))
ciphertext = cipher.encrypt(message)
nonce = b64encode(cipher.nonce).decode('ASCII')
ct = b64encode(ciphertext).decode('ASCII')
sendjson = json.dumps({'type': 'AUT', 'source': self.network.own_addr, 'nonce': nonce, 'message': ct}).encode(
cipher = ChaCha20_Poly1305.new(key=self.cipherkey)
header = json.dumps({'type': 'AUT', 'source': self.network.own_addr}).encode('UTF-8')
cipher.update(header)
ciphertext, tag = cipher.encrypt_and_digest(message)
nonce = b64encode(cipher.nonce).decode('UTF-8')
ct = b64encode(ciphertext).decode('UTF-8')
b64tag = b64encode(tag).decode('UTF-8')
sendjson = json.dumps({'header': b64encode(header).decode('UTF-8'), 'nonce': nonce, 'message': ct, 'tag': b64tag}).encode(
'UTF-8')
self.network.send_msg(self.serverAddr, sendjson)
b64 = {'source': '', 'type': ''}
@ -82,9 +85,11 @@ class NetWrapper:
try:
retnonce = b64decode(b64['nonce'])
retciphertext = b64decode(b64['message'])
retcipher = ChaCha20.new(key=self.cipherkey, nonce=retnonce)
plaintext = retcipher.decrypt(retciphertext).decode('UTF-8')
if plaintext != "OK":
retcipher = ChaCha20_Poly1305.new(key=self.cipherkey, nonce=retnonce)
retcipher.update(b64decode(b64['header']))
retheader = json.loads(b64decode(b64['header']).decode('UTF-8'))
plaintext = retcipher.decrypt_and_verify(retciphertext,b64decode(b64['tag'])).decode('UTF-8')
if plaintext != "OK" or not (retheader['source'] == self.serverAddr and retheader['type'] == 'AUT'):
raise Exception('Authentication error')
except Exception as e:
print(e)
@ -99,26 +104,29 @@ class NetWrapper:
self.authenticate(pw)
def sendMessage(self, message: bytes):
cipher = ChaCha20.new(key=self.cipherkey, nonce=get_random_bytes(12))
ciphertext = cipher.encrypt(message)
nonce = b64encode(cipher.nonce).decode('ASCII')
ct = b64encode(ciphertext).decode('ASCII')
sendjson = json.dumps({'type': 'CMD', 'source': self.network.own_addr, 'nonce': nonce, 'message': ct}).encode(
cipher = ChaCha20_Poly1305.new(key=self.cipherkey)
header = json.dumps({'type': 'CMD', 'source': self.network.own_addr}).encode('UTF-8')
cipher.update(header)
ciphertext, tag = cipher.encrypt_and_digest(message)
nonce = b64encode(cipher.nonce).decode('UTF-8')
ct = b64encode(ciphertext).decode('UTF-8')
sendjson = json.dumps({'header': b64encode(header).decode('UTF-8'), 'nonce': nonce, 'message': ct, 'tag': b64encode(tag).decode('UTF-8')}).encode(
'UTF-8')
self.network.send_msg(self.serverAddr, sendjson)
def recieveMessage(self) -> bytes:
b64 = {'source': '', 'type': ''}
while not (b64['source'] == self.serverAddr and b64['type'] == 'AUT'):
try:
status, msg = self.network.receive_msg(blocking=True)
if not status:
raise Exception('Network error during connection.')
b64 = json.loads(msg.decode('UTF-8'))
try:
retnonce = b64decode(b64['nonce'])
retciphertext = b64decode(b64['message'])
retcipher = ChaCha20.new(key=self.cipherkey, nonce=retnonce)
plaintext = retcipher.decrypt(retciphertext)
retcipher = ChaCha20_Poly1305.new(key=self.cipherkey, nonce=retnonce)
plaintext = retcipher.decrypt_and_verify(retciphertext,b64decode(b64['tag']))
retheader = json.loads(b64decode(b64['header']).decode('UTF-8'))
if not (retheader['source'] == self.serverAddr and retheader['type'] == 'CMD'):
return "ERROR".encode('UTF-8')
return plaintext
except Exception:
print("Incorrect decryption")