Removed PyCrypto code and translated to cryptography code

client-py3/full/src/uds/tools.py

@@ -29,10 +29,6 @@
 '''
 @author: Adolfo Gómez, dkmaster at dkmon dot com
 '''
-from __future__ import unicode_literals
-
-from base64 import b64decode
-
 import tempfile
 import string
 import random
@@ -41,8 +37,8 @@ import socket
 import stat
 import sys
 import time
+import base64
 
-import six
 
 from .log import logger
 
@@ -53,7 +49,7 @@ _execBeforeExit = []
 sys_fs_enc = sys.getfilesystemencoding() or 'mbcs'
 
 # Public key for scripts
-PUBLIC_KEY = '''-----BEGIN PUBLIC KEY-----
+PUBLIC_KEY = b'''-----BEGIN PUBLIC KEY-----
 MIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEAuNURlGjBpqbglkTTg2lh
 dU5qPbg9Q+RofoDDucGfrbY0pjB9ULgWXUetUWDZhFG241tNeKw+aYFTEorK5P+g
 ud7h9KfyJ6huhzln9eyDu3k+kjKUIB1PLtA3lZLZnBx7nmrHRody1u5lRaLVplsb
@@ -179,13 +175,21 @@ def verifySignature(script, signature):
     return: Boolean. True if the signature is valid; False otherwise.
     '''
     # For signature checking
-    from Crypto.PublicKey import RSA
-    from Crypto.Signature import PKCS1_v1_5
-    from Crypto.Hash import SHA256
+    from cryptography.hazmat.backends import default_backend
+    from cryptography.hazmat.primitives import serialization, hashes
+    from cryptography.hazmat.primitives.asymmetric import utils, padding
 
-    rsakey = RSA.importKey(PUBLIC_KEY)
-    signer = PKCS1_v1_5.new(rsakey)
-    digest = SHA256.new(script)  # Script is "binary string" here
-    if signer.verify(digest, b64decode(signature)):
-        return True
-    return False
+    public_key = serialization.load_pem_public_key(data=PUBLIC_KEY)
+
+    try:
+        public_key.verify(
+            base64.b64decode(signature),
+            script,
+            padding.PKCS1v15(),
+            hashes.SHA256()
+        )
+    except Exception:  # InvalidSignature
+        return False
+
+    # If no exception, the script was fine...
+    return True