Added authenticator

utils/auth_key.py

@@ -0,0 +1,30 @@
+# This file is based on TLSharp
+# https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/MTProto/Crypto/AuthKey.cs
+from hashlib import sha1
+from utils.binary_writer import BinaryWriter
+from utils.binary_reader import BinaryReader
+
+
+class AuthKey:
+    def __init__(self, gab=None, data=None):
+        if gab:
+            self.key = gab.to_byte_array_unsigned()
+        elif data:
+            self.key = data
+        else:
+            raise AssertionError('Either a gab integer or data bytes array must be provided')
+
+        with BinaryReader(sha1(self.key)) as reader:
+            self.aux_hash = reader.read_long(signed=False)
+            reader.read(4)
+            self.key_id = reader.read_long(signed=False)
+
+
+    def calc_new_nonce_hash(self, new_nonce, number):
+        with BinaryWriter() as writer:
+            writer.write(new_nonce)
+            writer.write_byte(number)
+            writer.write_long(self.aux_hash, signed=False)
+
+            new_nonce_hash = sha1(writer.get_bytes())[4:20]
+            return new_nonce_hash

utils/factorizator.py

@@ -0,0 +1,46 @@
+# This file is based on TLSharp
+# https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/MTProto/Crypto/Factorizator.cs
+from random import randint
+from math import gcd
+
+
+class Factorizator:
+    @staticmethod
+    def find_small_multiplier_lopatin(what):
+        g = 0
+        for i in range(3):
+            q = (randint(0, 127) & 15) + 17
+            x = randint(1000000000) + 1
+            y = x
+            lim = 1 << (i + 18)
+            for j in range(1, lim):
+                a, b, c = x, x, q
+                while b != 0:
+                    if (b & 1) != 0:
+                        c += a
+                        if c >= what:
+                            c -= what
+                    a += a
+                    if a >= what:
+                        a -= what
+                    b >>= 1
+
+                x = c
+                z = y - x if x < y else x - y
+                g = gcd(z, what)
+                if g != 1:
+                    break
+
+                if (j & (j - 1)) == 0:
+                    y = x
+
+            if g > 1:
+                break
+
+        p = what // g
+        return min(p, g)
+
+    @staticmethod
+    def factorize(pq):
+        divisor = Factorizator.find_small_multiplier_lopatin(pq)
+        return divisor, pq // divisor

utils/helpers.py

@@ -59,3 +59,40 @@ def calc_msg_key_offset(data, offset, limit):
     # TODO untested, may not be offset like this
     # In the original code it was as parameters for the sha function, not slicing the array
     return sha1(data[offset:offset + limit])[4:20]
+
+
+def generate_key_data_from_nonces(serverNonce, newNonce):
+    # TODO unsure that this works
+    nonces = [0] * 48
+
+    nonces[00:32] = newNonce
+    nonces[32:48] = serverNonce
+    hash1 = hash(bytes(nonces))
+
+    nonces[00:16] = serverNonce
+    nonces[16:32] = newNonce
+    hash2 = hash(bytes(nonces))
+
+    nonces = [0] * 64
+    nonces[00:32] = newNonce
+    nonces[32:64] = newNonce
+    hash2 = hash(bytes(nonces))
+
+    with BinaryWriter() as keyBuffer:
+        with BinaryWriter() as ivBuffer:
+            """
+                using (var keyBuffer = new MemoryStream(32))
+                using (var ivBuffer = new MemoryStream(32))
+                {
+                    keyBuffer.Write(hash1, 0, hash1.Length);
+                    keyBuffer.Write(hash2, 0, 12);
+
+                    ivBuffer.Write(hash2, 12, 8);
+                    ivBuffer.Write(hash3, 0, hash3.Length);
+                    ivBuffer.Write(newNonce, 0, 4);
+
+                    return new AESKeyData(keyBuffer.ToArray(), ivBuffer.ToArray());
+                }
+            """
+            # TODO implement
+            raise NotImplementedError()