2018s-onion-team4

Onion Messenger

Onion messenger is the messenger service that is inspired by onion routing.

It uses PGP to encrypt or decrypt messages.

Also, our messenger provides ascii art feature! You can send your favorite picture to others.

Build & Run

You can run our messenger in your own environment.

$ sudo apt install libncurses-dev libcurl4-openssl-dev g++ \
  golang-go apt-utils apt-utils
$ go get github.com/stdupp/goasciiart
$ make
$ ./OnionMessenger --help  # to show options
Usage: ./OnionMessenger [Options]

Required arguments
  --priv, -s : Private key file
  --pub,  -b : Public key file
  --port, -p : Server listen port

Optional arguments
  --notui    : Not use TUI
  --node, -n : Another client's IP
  --help, -h : Show this message

or use docker!

Command line

• Send msg /msg [Github_ID] [msg] or /m [Github_ID] [msg]
• Geturl to asciiart /img [Github_ID] [url] or /i [Github_ID] [url]
• Help message /help or /h

UI Overview

• Login UI

• Chat UI

• Chat UI with Asciiart

Architecture

• We use two threads + on-demand thread.
  • Thread #1: UI handler.
  • Thread #2: Packet handler.
  • On demand thread for PGP encrypt and decrypt.
• Distributed System: No single point of failure.
• IO multiplexing with select: Can handle lots of clients.
• Onion routing with PGP: All of your messages cannot be sniffed. Also, no one knows who is the sender and who is the receiver except you and receiver.

Protocol

There are two types of packet.

Handshake

| 0(uint8_t) | port(uint16_t) | GithubID Length(uint32_t) | GithubID(GithubIDLength) | PubkeyLength(uint32_t) | Pubkey(PubkeyLength)| # of connected node(uint32_t) | (# of connected node) entries of Node IP(uint32_t) |

Msg

| 1(uint8_t) | Length(uint32_t) | Cipher text(Length) |

Message type

Three types of message is embeded to msg packet.

OnionLayer: | 0 (uint8_t) | idLength(uint32_t) | id (idLength) | Data |

MessageLayer: | 1 (uint8_t) | Data |

ImageLayer: | 2 (uint8_t) | Url |

Team Member & Role

Name	Role
Hyunki Kim	Features & docs & Docker
Hongsik Kim	PGP & Features & Routing
Heeseok Kim	CUI
Minkyu Jung	All components