Peer-to-peer encypted communicator to send files and messages over TCP. Uses janus sync/async queues to pass data, PyQt5 for GUI, PyCryptodome for AES and asyncio for connection over TCP/IP.

One peer uses both client and server sockets - client socket is opened each time a message is sent.

message header (8B) = message type (4B) + message length (4B) (unsigned long)

• INIT - initialize connection - send address on which sender is listening
• PKEY - send public key
• SKEY - send session key encrypted with private key
• PARM - send AES parameters encrypted with private key
• TEXT - send a batch of text data encypted with AES algorithm
• FILE - send file data encrypted with AES algorithm:
  • INIT - initialize sending file - send filename
  • PARM - send size of a file in bytes
  • DATA - send a batch of file data
  • QUIT - signalize end of file data sending
• QUIT - signalize end of connection

parameters (18B) = algorithm type (1bit) + key size (2bits) + block size (8bit) + cipher mode (2bits) + padding (3 bits) + initial vector (16B)

• key size - 128, 192 or 256 bit
• cipher mode - ECB, CBC, CFB or OFB