This was ours (Bruno Moura, Rafael Remígio and João Teles) submission for our cybersecurity course's (SIO) second practical project.

At our first submission we received a 16.8 mark, and after further improvements we received a 19.2. Both out of 20.

Project Documentation

• File	Description
  Caller.py	Script for initializing the Caller process (requires nickname)
  Player.py	Script for initializing the Player process (requires nickname)
  PlayingArea.py	Script for initializing the Playing Area process (requires card and deck size)
  src/user.py	Generic logic for both the caller and player
  src/caller.py	Extends user.py and implements Caller specific logic
  src/player.py	Extends user.py and implements Player specific logic
  src/playing_area.py	Playing Area logic
  src/protocol.py	Contains the messages classes and functions for sending and receiveing messages through websockets
  src/crypto.py	Helper functions for cryptography operations
  src/common.py	Data types that are common to multiple classes. Namely player and log data.

  To test the project, run PlayingArea.py, Caller.py and at least two Player.py instances.

• Message

  Description	Generic message
  Methods	to_json(), should_log() returns True

• Authenticate

  Description	Message for Users to authenticate themselves to the playing area. Uses challenge-response authentication
  Extends	Message
  Methods	parse()
  Parameters	public_key challenge response success

• Register

  Description	Message for players to register themselves to the playing area
  Extends	Message
  Methods	parse()
  Parameters	nickname playing_key auth_key signature success sequence

• GetUsers

  Description	Message for getting a list of registered users
  Extends	Message
  Methods	parse(), should_log() returns false
  Parameters	public_key signature response

• CardSize

  Description	Simple message for letting users know the card size
  Extends	Message
  Methods	parse(), should_log() returns false
  Parameters	card_size

• GetLog

  Description	Message for getting a list of logged messages
  Extends	Message
  Methods	parse(), should_log() returns false
  Parameters	public_key signature response

  should_log -> returns false

• PartyUpdate

  Description	Message for updating registered users on how big the party is
  Extends	Message
  Methods	parse(), should_log() returns false
  Parameters	public_key signature response

  should_log -> returns false

• GenerateDeck

  Description	Message telling the caller to generate the deck and initiate the card generation proccess
  Extends	Message
  Methods	parse()
  Parameters	deck_size

• GenerateCard

  Description	Message Players will pass around until everyone has commited their card
  Extends	Message
  Methods	parse() sign(private_key : str) Description: Signs the deck with private_Key and append the public key to the signatures array Call our Cryptography function sign verify(publicKey : str, signature) Description: Verifies the signature of the deck with the public key Call our Cryptography function verify
  Parameters	sequence (int) deck (list) signatures (list) done (bool)

• DeckKeyRequest

  Description	Message requesting that players and caller reveal their symmetric key after the deck is commited
  Extends	Message
  Methods	parse()
  Parameters	sequence

• DeckKeyResponse

  Description	Response to the deck key request
  Extends	Message
  Methods	parse() sign(private_key : str) Description: Signs the response with private_Key and assigns it to signature Call our Cryptography function sign
  Parameters	sequence response signature

• GameOver

  Description	Message for when the game is over / aborted
  Extends	Message
  Methods	parse() should_log() returns false __ str __()
  Parameters	status

• Methods

  • send_msg

    Description	Sends through a connection a Message object.
    Parameters	connection: socket msg: Message
    Return	None

  • recv_msg

    Description	Receives through a connection a Message object.
    Parameters	connection: socket
    Return	Message

  • parse_msg

    Description	Returns from message string a Message Instance
    Parameters	msg_str: str
    Return	Message

• ProtoBadFormat (Class)

  Description	Exception when source message is not Proto.

Cryptographic utilities

Uses cryptography.hazmat.primitives

• sym_gen

  Description	Generates a new AESGCM (key, nonce) tuple
  Parameters
  Return	tuple

• sym_encrypt

  Description	Encrypts data given with given AESGCM key
  Parameters	key: bytes data nonce: bytes
  Return	bytes

• sym_decrypt

  Description	Decrypts encrypted data given with given AESGCM key
  Parameters	key: bytes crypted_data nonce: bytes
  Return	bytes

• do_hash

  Description	Returns an hash of a given data; Uses SHA256
  Parameters	data: bytes
  Return	bytes

• asym_gen

  Description	Encrypts data using given public key
  Parameters
  Return	bytes

• sign

  Description	Returns Signature of given data signed with given private key; Uses SHA256
  Parameters	private_key data
  Return	bytes

• verify

  Description	Verifies if given message matches with given signature; Uses SHA256
  Parameters	public_key message signature: bytes
  Return	bool