Use more straightforward calls of hashlib.sha1/sha256

telethon/crypto/auth_key.py

@@ -1,3 +1,5 @@
+from hashlib import sha1
+
 from .. import helpers as utils
 from ..utils import BinaryReader, BinaryWriter
 
@@ -6,7 +8,7 @@ class AuthKey:
     def __init__(self, data):
         self.key = data
 
-        with BinaryReader(utils.sha1(self.key)) as reader:
+        with BinaryReader(sha1(self.key).digest()) as reader:
             self.aux_hash = reader.read_long(signed=False)
             reader.read(4)
             self.key_id = reader.read_long(signed=False)

telethon/crypto/rsa.py

@@ -1,6 +1,6 @@
 import os
+from hashlib import sha1
 
-from .. import helpers as utils
 from ..utils import BinaryWriter
 
 
@@ -19,7 +19,7 @@ class RSAServerKey:
 
         with BinaryWriter() as writer:
             # Write SHA
-            writer.write(utils.sha1(data[offset:offset + length]))
+            writer.write(sha1(data[offset:offset + length]).digest())
             # Write data
             writer.write(data[offset:offset + length])
             # Add padding if required

telethon/helpers.py

@@ -1,4 +1,4 @@
-import hashlib
+from hashlib import sha1, sha256
 import os
 
 # region Multiple utilities
@@ -24,11 +24,12 @@ def calc_key(shared_key, msg_key, client):
     """Calculate the key based on Telegram guidelines, specifying whether it's the client or not"""
     x = 0 if client else 8
 
-    sha1a = sha1(msg_key + shared_key[x:x + 32])
-    sha1b = sha1(shared_key[x + 32:x + 48] + msg_key + shared_key[x + 48:x +
-                                                                  64])
-    sha1c = sha1(shared_key[x + 64:x + 96] + msg_key)
-    sha1d = sha1(msg_key + shared_key[x + 96:x + 128])
+    sha1a = sha1(msg_key + shared_key[x:x + 32]).digest()
+    sha1b = sha1(shared_key[x + 32:x + 48] + msg_key +
+                 shared_key[x + 48:x + 64]).digest()
+
+    sha1c = sha1(shared_key[x + 64:x + 96] + msg_key).digest()
+    sha1d = sha1(msg_key + shared_key[x + 96:x + 128]).digest()
 
     key = sha1a[0:8] + sha1b[8:20] + sha1c[4:16]
     iv = sha1a[8:20] + sha1b[0:8] + sha1c[16:20] + sha1d[0:8]
@@ -38,34 +39,20 @@ def calc_key(shared_key, msg_key, client):
 
 def calc_msg_key(data):
     """Calculates the message key from the given data"""
-    return sha1(data)[4:20]
+    return sha1(data).digest()[4:20]
 
 
 def generate_key_data_from_nonce(server_nonce, new_nonce):
     """Generates the key data corresponding to the given nonce"""
-    hash1 = sha1(bytes(new_nonce + server_nonce))
-    hash2 = sha1(bytes(server_nonce + new_nonce))
-    hash3 = sha1(bytes(new_nonce + new_nonce))
+    hash1 = sha1(bytes(new_nonce + server_nonce)).digest()
+    hash2 = sha1(bytes(server_nonce + new_nonce)).digest()
+    hash3 = sha1(bytes(new_nonce + new_nonce)).digest()
 
     key = hash1 + hash2[:12]
     iv = hash2[12:20] + hash3 + new_nonce[:4]
     return key, iv
 
 
-def sha1(data):
-    """Calculates the SHA1 digest for the given data"""
-    sha = hashlib.sha1()
-    sha.update(data)
-    return sha.digest()
-
-
-def sha256(data):
-    """Calculates the SHA256 digest for the given data"""
-    sha = hashlib.sha256()
-    sha.update(data)
-    return sha.digest()
-
-
 def get_password_hash(pw, current_salt):
     """Gets the password hash for the two-step verification.
        current_salt should be the byte array provided by invoking GetPasswordRequest()"""
@@ -76,6 +63,6 @@ def get_password_hash(pw, current_salt):
     data = pw.encode('utf-8')
 
     pw_hash = current_salt + data + current_salt
-    return sha256(pw_hash)
+    return sha256(pw_hash).digest()
 
 # endregion

telethon/network/authenticator.py

@@ -1,5 +1,6 @@
 import os
 import time
+from hashlib import sha1
 
 from .. import helpers as utils
 from ..crypto import AES, RSA, AuthKey, Factorization
@@ -162,11 +163,13 @@ def do_authentication(transport):
 
         with BinaryWriter() as client_dh_inner_data_with_hash_writer:
             client_dh_inner_data_with_hash_writer.write(
-                utils.sha1(client_dh_inner_data_writer.get_bytes()))
+                sha1(client_dh_inner_data_writer.get_bytes()).digest())
+
             client_dh_inner_data_with_hash_writer.write(
                 client_dh_inner_data_writer.get_bytes())
-            client_dh_inner_data_bytes = client_dh_inner_data_with_hash_writer.get_bytes(
-            )
+
+            client_dh_inner_data_bytes = \
+                client_dh_inner_data_with_hash_writer.get_bytes()
 
     # Encryption
     client_dh_inner_data_encrypted_bytes = AES.encrypt_ige(

telethon_tests/crypto_test.py

@@ -1,4 +1,5 @@
 import unittest
+from hashlib import sha1
 
 import telethon.helpers as utils
 from telethon.crypto import AES, Factorization
@@ -23,7 +24,7 @@ class CryptoTests(unittest.TestCase):
     def test_sha1():
         string = 'Example string'
 
-        hash_sum = utils.sha1(string.encode('utf-8'))
+        hash_sum = sha1(string.encode('utf-8')).digest()
         expected = b'\nT\x92|\x8d\x06:)\x99\x04\x8e\xf8j?\xc4\x8e\xd3}m9'
 
         assert hash_sum == expected, 'Invalid sha1 hash_sum representation (should be {}, but is {})'\