From 94ed33bb1534d5dd06b5c1778e0292ec35199f3a Mon Sep 17 00:00:00 2001
From: Anton Grigoryev <mail@griganton.ru>
Date: Tue, 17 Mar 2015 02:02:01 +0300
Subject: [PATCH] Start of refactoring

A lot of work to be done
---
 TL.py      | 145 +++++++++++++++++++++++
 mtproto.py | 331 ++++++++++++++++++++++++++---------------------------
 testing.py | 136 +---------------------
 3 files changed, 309 insertions(+), 303 deletions(-)
 create mode 100644 TL.py

diff --git a/TL.py b/TL.py
new file mode 100644
index 00000000..643df50a
--- /dev/null
+++ b/TL.py
@@ -0,0 +1,145 @@
+__author__ = 'agrigoryev'
+import os
+import struct
+import json
+import io
+import numbers
+
+class TlConstructor:
+    def __init__(self, json_dict):
+        self.id = int(json_dict['id'])
+        self.type = json_dict['type']
+        self.predicate = json_dict['predicate']
+        self.params = []
+        # case of vector
+        for param in json_dict['params']:
+            if param['type'] == "Vector<long>":
+                param['type'] = "Vector t"
+                param['subtype'] = "long"
+            else:
+                param['subtype'] = None
+            self.params.append(param)
+
+class TlMethod:
+    def __init__(self, json_dict):
+        self.id = int(json_dict['id'])
+        self.type = json_dict['type']
+        self.method = json_dict['method']
+        self.params = json_dict['params']
+
+
+class TL:
+    def __init__(self, filename):
+        with open(filename, 'r') as f:
+           TL_dict = json.load(f)
+
+        # Read constructors
+
+        self.constructors = TL_dict['constructors']
+        self.constructor_id = {}
+        self.constructor_type = {}
+        for elem in self.constructors:
+            z = TlConstructor(elem)
+            self.constructor_id[z.id] = z
+            self.constructor_type[z.predicate] = z
+
+        self.methods = TL_dict['methods']
+        self.method_id = {}
+        self.method_name = {}
+        for elem in self.methods:
+            z = TlMethod(elem)
+            self.method_id[z.id] = z
+            self.method_name[z.method] = z
+
+
+## Loading TL_schema (should be placed in the same directory as mtproto.py
+tl = TL(os.path.join(os.path.dirname(__file__), "TL_schema.JSON"))
+
+
+def serialize_obj(bytes_io, type_, **kwargs):
+    try:
+        tl_constructor = tl.constructor_type[type_]
+    except KeyError:
+        raise Exception("Could not extract type: %s" % type_)
+    bytes_io.write(struct.pack('<i', tl_constructor.id))
+    for arg in tl_constructor.params:
+        serialize_param(bytes_io, type_=arg['type'],  value=kwargs[arg['name']])
+
+
+def serialize_method(bytes_io, type_, **kwargs):
+    try:
+        tl_method = tl.method_name[type_]
+    except KeyError:
+        raise Exception("Could not extract type: %s" % type_)
+    bytes_io.write(struct.pack('<i', tl_method.id))
+    for arg in tl_method.params:
+        serialize_param(bytes_io, type_=arg['type'], value=kwargs[arg['name']])
+
+
+def serialize_param(bytes_io, type_, value):
+    if type_ == "int":
+        assert isinstance(value, int)
+        bytes_io.write(struct.pack('<i', value))
+    elif type_ == "long":
+        assert isinstance(value, numbers.Real)
+        bytes_io.write(struct.pack('<q', value))
+    elif type_ in ["int128", "int256"]:
+        assert isinstance(value, bytes)
+        bytes_io.write(value)
+    elif type_ == 'string' or 'bytes':
+        l = len(value)
+        if l < 254: # short string format
+            bytes_io.write(struct.pack('<b', l))  # 1 byte of string
+            bytes_io.write(value)   # string
+            bytes_io.write(b'\x00'*((-l-1) % 4))  # padding bytes
+        else:
+            bytes_io.write(b'\xfe')  # byte 254
+            bytes_io.write(struct.pack('<i', l)[:3])  # 3 bytes of string
+            bytes_io.write(value) # string
+            bytes_io.write(b'\x00'*(-l % 4))  # padding bytes
+
+def deserialize(bytes_io, type_=None, subtype=None):
+    """
+    :type bytes_io: io.BytesIO object
+    """
+    assert isinstance(bytes_io, io.BytesIO)
+
+    # Built-in bare types
+    if   type_ == 'int':    x = struct.unpack('<i', bytes_io.read(4))[0]
+    elif type_ == '#':      x = struct.unpack('<I', bytes_io.read(4))[0]
+    elif type_ == 'long':   x = struct.unpack('<q', bytes_io.read(8))[0]
+    elif type_ == 'double': x = struct.unpack('<d', bytes_io.read(8))[0]
+    elif type_ == 'int128': x = bytes_io.read(16)
+    elif type_ == 'int256': x = bytes_io.read(32)
+    elif type_ == 'string' or type_ == 'bytes':
+        l = struct.unpack('<B', bytes_io.read(1))[0]
+        assert l <= 254  # In general, 0xFF byte is not allowed here
+        if l == 254:
+            # We have a long string
+            long_len = struct.unpack('<I', bytes_io.read(3)+b'\x00')[0]
+            x = bytes_io.read(long_len)
+            bytes_io.read(-long_len % 4)  # skip padding bytes
+        else:
+            # We have a short string
+            x = bytes_io.read(l)
+            bytes_io.read(-(l+1) % 4)  # skip padding bytes
+        assert isinstance(x, bytes)
+    elif type_ == 'vector':
+        assert subtype is not None
+        count = struct.unpack('<l', bytes_io.read(4))[0]
+        x = [deserialize(bytes_io, type_=subtype) for i in range(count)]
+    else:
+        # Boxed types
+        i = struct.unpack('<i', bytes_io.read(4))[0]  # read type ID
+        try:
+            tl_elem = tl.constructor_id[i]
+        except KeyError:
+            raise Exception("Could not extract type: %s" % type_)
+        base_boxed_types = ["Vector t", "Int", "Long", "Double", "String", "Int128", "Int256"]
+        if tl_elem.type in base_boxed_types:
+            x = deserialize(bytes_io, type_=tl_elem.predicate, subtype=subtype)
+        else:  # other types
+            x = {}
+            for arg in tl_elem.params:
+                x[arg['name']] = deserialize(bytes_io, type_=arg['type'], subtype=arg['subtype'])
+    return x
\ No newline at end of file
diff --git a/mtproto.py b/mtproto.py
index 9774d654..56b0c9ad 100644
--- a/mtproto.py
+++ b/mtproto.py
@@ -6,10 +6,7 @@ Created on Tue Sep  2 19:26:15 2014
 @author: Sammy Pfeiffer
 """
 from binascii import crc32 as originalcrc32
-MIN_SUPPORTED_PY3_VERSION = (3, 2, 0)
 import numbers
-def crc32(data):
-    return originalcrc32(data) & 0xffffffff
 from datetime import datetime
 from time import time
 import io
@@ -18,6 +15,19 @@ import json
 import socket
 import struct
 
+# pycrypto module
+from Crypto.Hash import SHA
+from Crypto.PublicKey import RSA
+from Crypto.Util.strxor import strxor
+
+# local modules
+import crypt
+import prime
+import TL
+
+def crc32(data):
+    return originalcrc32(data) & 0xffffffff
+
 def vis(bs):
     """
     Function to visualize byte streams. Split into bytes, print to console.
@@ -32,156 +42,22 @@ def vis(bs):
         print(str((i+1)*symbols_in_one_line)+" | "+" ".join(["%02X" % b for b in bs[(i+1)*symbols_in_one_line:]])+"\n") # for last line
 
 
-class TlConstructor:
-    def __init__(self, json_dict):
-        self.id = int(json_dict['id'])
-        self.type = json_dict['type']
-        self.predicate = json_dict['predicate']
-        self.params = []
-        # case of vector
-        for param in json_dict['params']:
-            if param['type'] == "Vector<long>":
-                param['type'] = "Vector t"
-                param['subtype'] = "long"
-            else:
-                param['subtype'] = None
-            self.params.append(param)
 
-class TlMethod:
-    def __init__(self, json_dict):
-        self.id = int(json_dict['id'])
-        self.type = json_dict['type']
-        self.method = json_dict['method']
-        self.params = json_dict['params']
-
-
-class TL:
-    def __init__(self, filename):
-        with open(filename, 'r') as f:
-           TL_dict = json.load(f)
-
-        # Read constructors
-
-        self.constructors = TL_dict['constructors']
-        self.constructor_id = {}
-        self.constructor_type = {}
-        for elem in self.constructors:
-            z = TlConstructor(elem)
-            self.constructor_id[z.id] = z
-            self.constructor_type[z.predicate] = z
-
-        self.methods = TL_dict['methods']
-        self.method_id = {}
-        self.method_name = {}
-        for elem in self.methods:
-            z = TlMethod(elem)
-            self.method_id[z.id] = z
-            self.method_name[z.method] = z
-
-
-## Loading TL_schema (should be placed in the same directory as mtproto.py
-tl = TL(os.path.join(os.path.dirname(__file__), "TL_schema.JSON"))
-
-
-def serialize_obj(bytes_io, type_, **kwargs):
-    try:
-        tl_constructor = tl.constructor_type[type_]
-    except KeyError:
-        raise Exception("Could not extract type: %s" % type_)
-    bytes_io.write(struct.pack('<i', tl_constructor.id))
-    for arg in tl_constructor.params:
-        serialize_param(bytes_io, type_=arg['type'],  value=kwargs[arg['name']])
-
-
-def serialize_method(bytes_io, type_, **kwargs):
-    try:
-        tl_method = tl.method_name[type_]
-    except KeyError:
-        raise Exception("Could not extract type: %s" % type_)
-    bytes_io.write(struct.pack('<i', tl_method.id))
-    for arg in tl_method.params:
-        serialize_param(bytes_io, type_=arg['type'], value=kwargs[arg['name']])
-
-
-def serialize_param(bytes_io, type_, value):
-    if type_ == "int":
-        assert isinstance(value, int)
-        bytes_io.write(struct.pack('<i', value))
-    elif type_ == "long":
-        assert isinstance(value, numbers.Real)
-        bytes_io.write(struct.pack('<q', value))
-    elif type_ in ["int128", "int256"]:
-        assert isinstance(value, bytes)
-        bytes_io.write(value)
-    elif type_ == 'string' or 'bytes':
-        l = len(value)
-        if l < 254: # short string format
-            bytes_io.write(struct.pack('<b', l))  # 1 byte of string
-            bytes_io.write(value)   # string
-            bytes_io.write(b'\x00'*((-l-1) % 4))  # padding bytes
-        else:
-            bytes_io.write(b'\xfe')  # byte 254
-            bytes_io.write(struct.pack('<i', l)[:3])  # 3 bytes of string
-            bytes_io.write(value) # string
-            bytes_io.write(b'\x00'*(-l % 4))  # padding bytes
-
-def deserialize(bytes_io, type_=None, subtype=None):
-    """
-    :type bytes_io: io.BytesIO object
-    """
-    assert isinstance(bytes_io, io.BytesIO)
-
-    # Built-in bare types
-    if   type_ == 'int':    x = struct.unpack('<i', bytes_io.read(4))[0]
-    elif type_ == '#':      x = struct.unpack('<I', bytes_io.read(4))[0]
-    elif type_ == 'long':   x = struct.unpack('<q', bytes_io.read(8))[0]
-    elif type_ == 'double': x = struct.unpack('<d', bytes_io.read(8))[0]
-    elif type_ == 'int128': x = bytes_io.read(16)
-    elif type_ == 'int256': x = bytes_io.read(32)
-    elif type_ == 'string' or type_ == 'bytes':
-        l = struct.unpack('<B', bytes_io.read(1))[0]
-        assert l <= 254  # In general, 0xFF byte is not allowed here
-        if l == 254:
-            # We have a long string
-            long_len = struct.unpack('<I', bytes_io.read(3)+b'\x00')[0]
-            x = bytes_io.read(long_len)
-            bytes_io.read(-long_len % 4)  # skip padding bytes
-        else:
-            # We have a short string
-            x = bytes_io.read(l)
-            bytes_io.read(-(l+1) % 4)  # skip padding bytes
-        assert isinstance(x, bytes)
-    elif type_ == 'vector':
-        assert subtype is not None
-        count = struct.unpack('<l', bytes_io.read(4))[0]
-        print("count is: " + str(count))
-        x = [deserialize(bytes_io, type_=subtype) for i in range(count)]
-    else:
-        # Boxed types
-        i = struct.unpack('<i', bytes_io.read(4))[0]  # read type ID
-        try:
-            tl_elem = tl.constructor_id[i]
-        except KeyError:
-            raise Exception("Could not extract type: %s" % type_)
-        base_boxed_types = ["Vector t", "Int", "Long", "Double", "String", "Int128", "Int256"]
-        if tl_elem.type in base_boxed_types:
-            x = deserialize(bytes_io, type_=tl_elem.predicate, subtype=subtype)
-        else:  # other types
-            x = {}
-            for arg in tl_elem.params:
-                x[arg['name']] = deserialize(bytes_io, type_=arg['type'], subtype=arg['subtype'])
-    return x
 
 
 class Session:
     """ Manages TCP Transport. encryption and message frames """
-    def __init__(self, ip, port, auth_key_id=None):
+    def __init__(self, ip, port, auth_key=None):
         # creating socket
         self.sock = socket.socket()
         self.sock.connect((ip, port))
-        self.auth_key_id = auth_key_id
         self.number = 0
 
+        if auth_key is None:
+            self.create_auth_key()
+        else:
+            self.auth_key = auth_key
+
     def __del__(self):
         # closing socket when session object is deleted
         self.sock.close()
@@ -203,7 +79,7 @@ class Session:
 
         return (b'\x00\x00\x00\x00\x00\x00\x00\x00' +
                 struct.pack('<Q', msg_id) +
-                struct.pack('<L', len(message)))
+                struct.pack('<I', len(message)))
 
     # TCP Transport
 
@@ -219,16 +95,14 @@ class Session:
         Forming the message frame and sending message to server
         :param message: byte string to send
         """
-
-
         data = self.header_unencrypted(message) + message
-        step1 = struct.pack('<LL', len(data)+12, self.number) + data
-        step2 = step1 + struct.pack('<L', crc32(step1))
+        step1 = struct.pack('<II', len(data)+12, self.number) + data
+        step2 = step1 + struct.pack('<I', crc32(step1))
         self.sock.send(step2)
         self.number += 1
         # Sending message visualisation to console
-        print('>>')
-        vis(step2)
+#        print('>>')
+ #       vis(step2)
 
     def recv_message(self):
         """
@@ -237,27 +111,13 @@ class Session:
         packet_length_data = self.sock.recv(4)  # reads how many bytes to read
 
         if len(packet_length_data) > 0:  # if we have smth. in the socket
-            packet_length = struct.unpack("<L", packet_length_data)[0]
+            packet_length = struct.unpack("<I", packet_length_data)[0]
             packet = self.sock.recv(packet_length - 4)  # read the rest of bytes from socket
-
-            # Received message visualisation to console
-            print('<<')
-            vis(packet_length_data+packet)
-
-            (x, auth_key_id, message_id, message_length)= struct.unpack("<L8s8sI", packet[0:24])
+            (x, auth_key_id, message_id, message_length)= struct.unpack("<I8s8sI", packet[0:24])
             data = packet[24:24+message_length]
             crc = packet[-4:]
-            # print("crc is: " + str(crc))
-            # print("type of crc: " + str(type(crc)))
-            # print("crc.__repr__(): " + crc.__repr__())
-            # print("struct.unpack('<L', crc): (next line)")
-            # print(struct.unpack('<L', crc))
-            # print("crc32(packet_length_data + packet[0:-4]): " + str(crc32(packet_length_data + packet[0:-4])))
-            # print("crc32(packet_length_data + packet[0:-4]).__repr__(): " + crc32(packet_length_data + packet[0:-4]).__repr__())
-
             # Checking the CRC32 correctness of received data
-            if crc32(packet_length_data + packet[0:-4]) == struct.unpack('<L', crc)[0]:
-
+            if crc32(packet_length_data + packet[0:-4]) == struct.unpack('<I', crc)[0]:
                 return data
             else:
                 raise Exception("CRC32 was not correct!")
@@ -266,7 +126,7 @@ class Session:
 
     def method_call(self, method, **kwargs):
         z=io.BytesIO()
-        serialize_method(z, method, **kwargs)
+        TL.serialize_method(z, method, **kwargs)
         # z.getvalue() on py2.7 returns str, which means bytes
         # on py3.4 returns bytes
         # bytearray is closer to the same data type to be shared
@@ -276,4 +136,137 @@ class Session:
         # print("len of z_val: " + str(len(z_val)))
         self.send_message(z_val)
         server_answer = self.recv_message()
-        return deserialize(io.BytesIO(server_answer))
+        return TL.deserialize(io.BytesIO(server_answer))
+
+    def create_auth_key(self):
+
+        nonce = os.urandom(16)
+        print("Requesting PQ")
+
+        ResPQ = self.method_call('req_pq', nonce=nonce)
+        server_nonce = ResPQ['server_nonce']
+
+        # TODO: selecting RSA public key based on this fingerprint
+        public_key_fingerprint = ResPQ['server_public_key_fingerprints'][0]
+
+        PQ_bytes = ResPQ['pq']
+
+        # TODO: from_bytes here
+        PQ = struct.unpack('>q', PQ_bytes)[0]
+        [p, q] = prime.primefactors(PQ)
+        if p > q: (p, q) = (q, p)
+        assert p*q == PQ and p < q
+
+        print("Factorization %d = %d * %d" % (PQ, p, q))
+
+        # TODO: to_bytes here
+        P_bytes = struct.pack('>i', p)
+        Q_bytes = struct.pack('>i', q)
+
+        f = open(os.path.join(os.path.dirname(__file__), "rsa.pub"))
+
+        key = RSA.importKey(f.read())
+
+        z = io.BytesIO()
+
+        new_nonce = os.urandom(32)
+
+        TL.serialize_obj(z, 'p_q_inner_data',
+                              pq=PQ_bytes,
+                              p=P_bytes,
+                              q=Q_bytes,
+                              nonce=nonce,
+                              server_nonce=server_nonce,
+                              new_nonce=new_nonce)
+        data = z.getvalue()
+
+        sha_digest = SHA.new(data).digest()
+        random_bytes = os.urandom(255-len(data)-len(sha_digest))
+        to_encrypt = sha_digest + data + random_bytes
+        encrypted_data = key.encrypt(to_encrypt, 0)[0]
+
+        print("Starting Diffie Hellman key exchange")
+        server_DH_params = self.method_call('req_DH_params',
+                                nonce=nonce, # 16 bytes
+                                server_nonce=server_nonce,
+                                p=P_bytes,
+                                q=Q_bytes,
+                                public_key_fingerprint=public_key_fingerprint,
+                                encrypted_data=encrypted_data)
+        assert nonce == server_DH_params['nonce']
+        assert server_nonce == server_DH_params['server_nonce']
+
+        encrypted_answer = server_DH_params['encrypted_answer']
+
+        tmp_aes_key = SHA.new(new_nonce + server_nonce).digest() + SHA.new(server_nonce + new_nonce).digest()[0:12]
+        tmp_aes_iv = SHA.new(server_nonce + new_nonce).digest()[12:20] + SHA.new(new_nonce + new_nonce).digest() + new_nonce[0:4]
+
+        crypter = crypt.IGE(tmp_aes_key, tmp_aes_iv)
+
+        answer_with_hash = crypter.decrypt(encrypted_answer)
+
+        answer_hash = answer_with_hash[:20]
+        answer = answer_with_hash[20:]
+        # TODO: SHA hash assertion here
+
+        server_DH_inner_data = TL.deserialize(io.BytesIO(answer))
+        assert nonce == server_DH_inner_data['nonce']
+        assert server_nonce == server_DH_inner_data['server_nonce']
+        dh_prime_str = server_DH_inner_data['dh_prime']
+        g = server_DH_inner_data['g']
+        g_a_str = server_DH_inner_data['g_a']
+        server_time = server_DH_inner_data['server_time']
+        self.timedelta = server_time - time()
+        print("Server-client time delta = %.1f s" % self.timedelta)
+
+        dh_prime = int.from_bytes(dh_prime_str,'big')
+        g_a = int.from_bytes(g_a_str,'big')
+        assert prime.isprime(dh_prime)
+        retry_id = 0
+        while retry_id<25:
+            try:
+                b_str = os.urandom(256)
+                b = int.from_bytes(b_str,'big')
+                g_b = pow(g,b,dh_prime)
+
+                g_b_str = int.to_bytes(g_b, g_b.bit_length() // 8 + 1, 'big')
+
+                z = io.BytesIO()
+                TL.serialize_obj(z, 'client_DH_inner_data',
+                                      nonce=nonce,
+                                      server_nonce=server_nonce,
+                                      retry_id=retry_id,
+                                      g_b=g_b_str)
+                data = z.getvalue()
+                data_with_sha = SHA.new(data).digest()+data
+                data_with_sha_padded = data_with_sha + os.urandom(-len(data_with_sha) % 16)
+                encrypted_data = crypter.encrypt(data_with_sha_padded)
+
+                Set_client_DH_params_answer = self.method_call('set_client_DH_params',
+                                                                   nonce=nonce,
+                                                                   server_nonce=server_nonce,
+                                                                   encrypted_data=encrypted_data)
+
+                auth_key = pow(g_a, b, dh_prime)
+                auth_key_str = int.to_bytes(auth_key, auth_key.bit_length() // 8 + 1, 'big')
+                auth_key_sha = SHA.new(auth_key_str).digest()
+                auth_key_hash = auth_key_sha[-8:]
+                auth_key_aux_hash = auth_key_sha[:8]
+
+                new_nonce_hash1 = SHA.new(new_nonce+b'\x01'+auth_key_aux_hash).digest()[-16:]
+                new_nonce_hash2 = SHA.new(new_nonce+b'\x02'+auth_key_aux_hash).digest()[-16:]
+                new_nonce_hash3 = SHA.new(new_nonce+b'\x03'+auth_key_aux_hash).digest()[-16:]
+
+                assert Set_client_DH_params_answer['nonce'] == nonce
+                assert Set_client_DH_params_answer['server_nonce'] == server_nonce
+                assert Set_client_DH_params_answer['new_nonce_hash1'] == new_nonce_hash1
+                print("Diffie Hellman key exchange processed successfully")
+
+                self.server_salt = strxor(new_nonce[0:8], server_nonce[0:8])
+                self.auth_key = auth_key_str
+                print("Auth key generated")
+                break
+            except:
+                print("Retry DH key exchange")
+                retry_id += 1
+
diff --git a/testing.py b/testing.py
index 4d1c9a2f..294626a8 100644
--- a/testing.py
+++ b/testing.py
@@ -7,14 +7,8 @@ try: # this only works in py2.7
     import configparser
 except ImportError:
     import ConfigParser as configparser
-from Crypto.Hash import SHA
-from Crypto.PublicKey import RSA
-from Crypto.Util.strxor import strxor
-
-# local modules
-import crypt
 import mtproto
-import prime
+
 
 
 config = configparser.ConfigParser()
@@ -25,130 +19,4 @@ if not config.read('credentials'):
 ip = config.get('App data', 'ip_address')
 port = config.getint('App data', 'port')
 
-Session = mtproto.Session(ip, port)
-client_nonce = os.urandom(16)
-x = Session.method_call('req_pq', nonce=client_nonce)
-
-server_nonce = x['server_nonce']
-public_key_fingerprint = x['server_public_key_fingerprints'][0]
-# TODO: selecting RSA public key based on this fingerprint
-PQ_bytes = x['pq']
-
-# doing len(PQ_bytes) I saw it was 8 bytes, so we unpack with Q
-# as in the docs: https://docs.python.org/2/library/struct.html
-PQ = struct.unpack('>q', PQ_bytes)[0]
-[p, q] = prime.primefactors(PQ)
-if p > q: (p, q) = (q, p)
-assert p*q == PQ and p < q
-
-print("PQ = %d\np = %d, q = %d" % (PQ, p, q))
-
-P_bytes = struct.pack('>i', p)
-Q_bytes = struct.pack('>i', q)
-
-f = open('rsa.pub', 'r')
-key = RSA.importKey(f.read())
-
-z = io.BytesIO()
-
-new_nonce = os.urandom(32)
-
-mtproto.serialize_obj(z, 'p_q_inner_data',
-                      pq=PQ_bytes,
-                      p=P_bytes,
-                      q=Q_bytes,
-                      nonce=client_nonce,
-                      server_nonce=server_nonce,
-                      new_nonce=new_nonce)
-data = z.getvalue()
-
-sha_digest = SHA.new(data).digest()
-random_bytes = os.urandom(255-len(data)-len(sha_digest))
-to_encrypt = sha_digest + data + random_bytes
-encrypted_data = key.encrypt(to_encrypt, 0)[0]
-
-server_DH_params = Session.method_call('req_DH_params',
-                        nonce=client_nonce, # 16 bytes
-                        server_nonce=server_nonce,
-                        p=P_bytes,
-                        q=Q_bytes,
-                        public_key_fingerprint=public_key_fingerprint,
-                        encrypted_data=encrypted_data)
-assert client_nonce == server_DH_params['nonce']
-assert server_nonce == server_DH_params['server_nonce']
-
-encrypted_answer = server_DH_params['encrypted_answer']
-
-tmp_aes_key = SHA.new(new_nonce + server_nonce).digest() + SHA.new(server_nonce + new_nonce).digest()[0:12]
-tmp_aes_iv = SHA.new(server_nonce + new_nonce).digest()[12:20] + SHA.new(new_nonce + new_nonce).digest() + new_nonce[0:4]
-
-crypter = crypt.IGE(tmp_aes_key, tmp_aes_iv)
-
-answer_with_hash = crypter.decrypt(encrypted_answer)
-
-answer_hash = answer_with_hash[:20]
-answer = answer_with_hash[20:]
-mtproto.vis(answer) # To start off BA0D89 ...
-
-server_DH_inner_data = mtproto.deserialize(io.BytesIO(answer))
-assert client_nonce == server_DH_inner_data['nonce']
-assert server_nonce == server_DH_inner_data['server_nonce']
-dh_prime_str = server_DH_inner_data['dh_prime']
-g = server_DH_inner_data['g']
-g_a_str = server_DH_inner_data['g_a']
-server_time = server_DH_inner_data['server_time']
-
-
-dh_prime = int.from_bytes(dh_prime_str,'big')
-g_a = int.from_bytes(g_a_str,'big')
-print(dh_prime)
-print(g)
-print(g_a)
-print(prime.isprime(dh_prime))
-
-b_str = os.urandom(256)
-b = int.from_bytes(b_str,'big')
-g_b = pow(g,b,dh_prime)
-
-g_b_str = int.to_bytes(g_b, g_b.bit_length() // 8 + 1, 'big')
-
-
-retry_id = 0
-z = io.BytesIO()
-mtproto.serialize_obj(z, 'client_DH_inner_data',
-                      nonce=client_nonce,
-                      server_nonce=server_nonce,
-                      retry_id=retry_id,
-                      g_b=g_b_str)
-data = z.getvalue()
-data_with_sha = SHA.new(data).digest()+data
-data_with_sha_padded = data_with_sha + os.urandom(-len(data_with_sha) % 16)
-encrypted_data = crypter.encrypt(data_with_sha_padded)
-
-Set_client_DH_params_answer = Session.method_call('set_client_DH_params',
-                                                   nonce=client_nonce,
-                                                   server_nonce=server_nonce,
-                                                   encrypted_data=encrypted_data)
-print(encrypted_data)
-print(Set_client_DH_params_answer)
-
-auth_key = pow(g_a, b, dh_prime)
-auth_key_str = int.to_bytes(auth_key, auth_key.bit_length() // 8 + 1, 'big')
-print("auth_key = %d" % auth_key)
-
-auth_key_sha = SHA.new(auth_key_str).digest()
-auth_key_hash = auth_key_sha[-8:]
-auth_key_aux_hash = auth_key_sha[:8]
-
-new_nonce_hash1 = SHA.new(new_nonce+b'\x01'+auth_key_aux_hash).digest()[-16:]
-new_nonce_hash2 = SHA.new(new_nonce+b'\x02'+auth_key_aux_hash).digest()[-16:]
-new_nonce_hash3 = SHA.new(new_nonce+b'\x03'+auth_key_aux_hash).digest()[-16:]
-
-assert Set_client_DH_params_answer['nonce'] == client_nonce
-assert Set_client_DH_params_answer['server_nonce'] == server_nonce
-assert Set_client_DH_params_answer['new_nonce_hash1'] == new_nonce_hash1
-
-Session.__del__()
-
-server_salt = strxor(new_nonce[0:8], server_nonce[0:8])
-mtproto.vis(server_salt)
\ No newline at end of file
+Session = mtproto.Session(ip, port)
\ No newline at end of file