diff --git a/mods/utcp.py b/mods/utcp.py
index cba1c83..647f42f 100644
--- a/mods/utcp.py
+++ b/mods/utcp.py
@@ -19,12 +19,6 @@ PACKET_END = b'___+++^^^END^^^+++___'
 AF_INET = None
 SOCK_STREAM = None
 
-class KeyPair:
-    my_key = None
-    peer_pub = None
-    def __init__(self, sec):
-        self.my_key = sec
-
 class Connection:
     SMALLEST_STARTING_SEQ = 0
     HIGHEST_STARTING_SEQ = 4294967295
@@ -34,7 +28,7 @@ class Connection:
         self.seq = Connection.gen_starting_seq_num()
         self.my_key = None
         if encrypted:
-            self.my_key = KeyPair(simplecrypto.RsaKeypair())
+            self.my_key = simplecrypto.RsaKeypair()
             self.pubkey = self.my_key.publickey.serialize()
         self.peer_pub = None
         self.recv_lock = threading.Lock()
@@ -55,6 +49,7 @@ class TCPPacket(object):
         self.ack = 0
         self.flag_ack = 0
         self.flag_syn = 0
+        self.flag_fin = 0
         self.checksum = 0
         self.data = b''
     def __repr__(self):
@@ -206,18 +201,15 @@ class TCP(object):
                     connection = list(self.connections.keys())[0]
                 else:
                     raise EOFError('Connection not in connected devices')
+            conn = self.connections[connection]
             data_parts = TCP.data_divider(data)
             for data_part in data_parts:
-                data_chunk = data_part if not self.encrypted else self.peer_keypair[connection].peer_pub.encrypt_raw(data_part)
-                checksum_of_data = TCP.checksum(data_chunk)
-                self.connections[connection].checksum = checksum_of_data
-                self.connections[connection].data = data_chunk
-                self.connections[connection].set_flags()
-                packet_to_send = pickle.dumps(self.connections[connection])
-                self.connections[connection].checksum = 0
-                self.connections[connection].data = b''
+                data_chunk = data_part if not self.encrypted else conn.peer_pub.encrypt_raw(data_part)
+                packet = TCPPacket(conn.seq)
+                packet.set_data(data_chunk)
+                packet_to_send = pickle.dumps(packet)
                 answer = self.retransmit(connection, packet_to_send)
-                self.connections[connection].seq += len(data_part)
+                conn.seq_inc(len(data_part))
             return len(data)
         except socket.error as error:
             raise EOFError('Socket was closed before executing command. Error is: %s.' % error)
@@ -269,9 +261,8 @@ class TCP(object):
                             conn = Connection(address, self.encrypted)
                             if self.encrypted:
                                 try:
-                                    conn.peer_pub = answer.data
+                                    conn.peer_pub = simplecrypto.RsaPublicKey(answer.data)
                                 except:
-                                    self.peer_keypair.pop(address)
                                     raise socket.error('Init peer public key error')
                             self.connection_queue.append((answer, conn))
                             self.blink_new_conn_event()
@@ -329,7 +320,7 @@ class TCP(object):
             self.client = True
             self.central_receive()
             conn = Connection(server_address, self.encrypted)
-            self.connections[server_address] = Connection(server_address, self.encrypted)
+            self.connections[server_address] = conn
             syn_packet = TCPPacket(conn.seq)
             syn_packet.set_flags(syn=True)
             if self.encrypted:
@@ -354,7 +345,6 @@ class TCP(object):
         except socket.error as error:
             self.own_socket.close()
             self.connections = {}
-            self.peer_keypair = {}
             self.status = 0
             raise EOFError('The socket was closed. Error:' + str(error))
     def fileno(self):
@@ -366,8 +356,6 @@ class TCP(object):
         with self.connection_lock:
             if len(self.connections):
                 self.connections.pop(connection)
-            if len(self.peer_keypair):
-                self.peer_keypair.pop(connection)
     def close(self, connection=None):
         try:
             if connection not in list(self.connections.keys()):
@@ -430,14 +418,15 @@ class TCP(object):
                 if address[0] == 'Any':
                     order = self.packets_received[condition].popitem()  # to reverse the tuple received
                     return order[1], order[0]
+                conn = self.connections[address]
                 if condition == 'ACK':
                     tries += 1
                 if condition == 'DATA or FIN':
-                    with self.connection_lock:
+                    with conn.recv_lock:
                         packet = self.packets_received[condition][address][:size]
                         self.packets_received[condition][address] = self.packets_received[condition][address][size:]
-                    if not len(self.packets_received[condition][address]):
-                        del self.packets_received[condition][address]
+                        if not len(self.packets_received[condition][address]):
+                            del self.packets_received[condition][address]
                 else:
                     packet = self.packets_received[condition].pop(address)
                 return packet
@@ -457,9 +446,10 @@ class TCP(object):
             self.disconnect(address)
         elif packet.packet_type() == 'DATA':
             if packet.checksum == TCP.checksum(packet.data):
-                data_chunk = packet.data if not self.encrypted else self.peer_keypair[address].my_key.decrypt_raw(packet.data)
+                conn = self.connections[address]
+                data_chunk = packet.data if not self.encrypted else conn.my_key.decrypt_raw(packet.data)
                 if data_chunk != PACKET_END:
-                    with self.connection_lock:
+                    with conn.recv_lock:
                         if address not in self.packets_received['DATA or FIN']:
                             self.packets_received['DATA or FIN'][address] = b''
                         self.packets_received['DATA or FIN'][address] += data_chunk