Various small fixes and cleanups

tests/vectors/*:
- removed noise-c-basic.txt test vectors

tests/test_vectors.py:
- removed workarounds related to noise-c test vectors

noise/builder.py:
- added some more type hinting

noise/state.py:
- CipherState is now consistent in raising NoiseMaxNonceError
and using MAX_NONCE constant for encrypt and decrypt methods

noise/functions.py:
- Keypair constructors now guarded from invalid length of given
public/private bytes
- _25519_generate_keypair now returns proper class instance

requirements.txt:
- specified versions of packages that are compatible with currently used source code

noise/builder.py

@@ -125,12 +125,12 @@ class NoiseBuilder(object):
             self.handshake_finished = True
         return buffer
 
-    def encrypt(self, data: bytes):
+    def encrypt(self, data: bytes) -> bytes:
         if not isinstance(data, bytes) or len(data) > MAX_MESSAGE_LEN:
             raise NoiseInvalidMessage('Data must be bytes and less or equal {} bytes in length'.format(MAX_MESSAGE_LEN))
         return self.noise_protocol.cipher_state_encrypt.encrypt_with_ad(None, data)
 
-    def decrypt(self, data: bytes):
+    def decrypt(self, data: bytes) -> bytes:
         if not isinstance(data, bytes) or len(data) > MAX_MESSAGE_LEN:
             raise NoiseInvalidMessage('Data must be bytes and less or equal {} bytes in length'.format(MAX_MESSAGE_LEN))
         try:

noise/functions.py

@@ -11,6 +11,7 @@ from cryptography.hazmat.primitives.asymmetric import x25519
 from cryptography.hazmat.primitives.ciphers.aead import AESGCM, ChaCha20Poly1305
 # from cryptography.hazmat.primitives.hmac import HMAC  # Turn back on when Cryptography gets fixed
 from noise.constants import MAX_NONCE
+from noise.exceptions import NoiseValueError
 from .crypto import X448
 
 backend = default_backend()
@@ -36,15 +37,19 @@ class DH(object):
     def _25519_generate_keypair(self) -> '_KeyPair':
         private_key = x25519.X25519PrivateKey.generate()
         public_key = private_key.public_key()
-        return _KeyPair(private_key, public_key, public_key.public_bytes())
+        return KeyPair25519(private_key, public_key, public_key.public_bytes())
 
     def _25519_dh(self, private_key: 'x25519.X25519PrivateKey', public_key: 'x25519.X25519PublicKey') -> bytes:
+        if not isinstance(private_key, x25519.X25519PrivateKey) or not isinstance(public_key, x25519.X25519PublicKey):
+            raise NoiseValueError('Invalid keys! Must be x25519.X25519PrivateKey and x25519.X25519PublicKey instances')
         return private_key.exchange(public_key)
 
     def _448_generate_keypair(self) -> '_KeyPair':
         return KeyPair448.new()
 
     def _448_dh(self, private_key: bytes, public_key: bytes) -> bytes:
+        if len(private_key) != self.dhlen or len(public_key) != self.dhlen:
+            raise NoiseValueError('Invalid length of keys! Should be {}'.format(self.dhlen))
         return X448.mul(private_key, public_key)
 
 
@@ -176,12 +181,16 @@ class _KeyPair(object):
 class KeyPair25519(_KeyPair):
     @classmethod
     def from_private_bytes(cls, private_bytes):
+        if len(private_bytes) != 32:
+            raise NoiseValueError('Invalid length of private_bytes! Should be 32')
         private = x25519.X25519PrivateKey._from_private_bytes(private_bytes)
         public = private.public_key()
         return cls(private=private, public=public, public_bytes=public.public_bytes())
 
     @classmethod
     def from_public_bytes(cls, public_bytes):
+        if len(public_bytes) != 32:
+            raise NoiseValueError('Invalid length of public_bytes! Should be 32')
         public = x25519.X25519PublicKey.from_public_bytes(public_bytes)
         return cls(public=public, public_bytes=public.public_bytes())
 
@@ -193,12 +202,16 @@ class KeyPair448(_KeyPair):
 
     @classmethod
     def from_private_bytes(cls, private_bytes):
+        if len(private_bytes) != 56:
+            raise NoiseValueError('Invalid length of private_bytes! Should be 56')
         private = private_bytes
         public = X448.mul_5(private)
         return cls(private=private, public=public, public_bytes=public)
 
     @classmethod
     def from_public_bytes(cls, public_bytes):
+        if len(public_bytes) != 56:
+            raise NoiseValueError('Invalid length of private_bytes! Should be 56')
         return cls(public=public_bytes, public_bytes=public_bytes)
 
     @classmethod

noise/state.py

@@ -36,7 +36,7 @@ class CipherState(object):
         :return: ciphertext bytes sequence
         """
         if self.n == MAX_NONCE:
-            raise Exception('Nonce has depleted!')
+            raise NoiseMaxNonceError('Nonce has depleted!')
 
         if not self.has_key():
             return plaintext
@@ -53,7 +53,7 @@ class CipherState(object):
         :param ciphertext: bytes sequence
         :return: plaintext bytes sequence
         """
-        if self.n == 2**64 - 1:
+        if self.n == MAX_NONCE:
             raise NoiseMaxNonceError('Nonce has depleted!')
 
         if not self.has_key():

requirements.txt

@@ -1,2 +1,2 @@
-pytest
-cryptography
+pytest>=3.2.2
+cryptography==2.0.3

tests/test_vectors.py

@@ -1,11 +1,9 @@
-import io
 import json
 import logging
 import os
 
 import pytest
 
-from noise.state import CipherState
 from noise.builder import NoiseBuilder, Keypair
 
 logger = logging.getLogger(__name__)
@@ -32,10 +30,6 @@ def _prepare_test_vectors():
             vectors_list = json.load(fd)
 
         for vector in vectors_list:
-            if 'name' in vector and not 'protocol_name' in vector:  # noise-c-* workaround
-                vector['protocol_name'] = vector['name']
-            if 'PSK' in vector['protocol_name']:  # no old NoisePSK tests
-                continue  # TODO REMOVE WHEN rev30 SUPPORT IS IMPLEMENTED/FIXED
             for key, value in vector.copy().items():
                 if key in byte_fields:
                     vector[key] = value.encode()

tests/vectors/README.md

@@ -1,4 +1,3 @@
 Test vectors:
 - cacophony.txt from https://github.com/centromere/cacophony/blob/master/vectors/cacophony.txt, stripped from outer dict (so that it is just a list of json objects)
-- noise-c-basic.txt from https://github.com/rweather/noise-c/blob/master/tests/vector/noise-c-basic.txt, stripped from outer dict (so that it is just a list of json objects)
 - snow-multipsk.txt from https://github.com/mcginty/snow/blob/master/tests/vectors/snow-multipsk.txt, stripped from outer dict (so that it is just a list of json objects)