deadchat

About

deadchat is a cryptographically secure single-room group chat server and client designed to enable a group of trusted friends to communicate with each other over an insecure channel without fear of eavesdropping.

deadchat features end-to-end encryption where messages are encrypted and decrypted at the end points such that the server and malicious machines on the network cannot eavesdrop on the conversation.

It is assumed that a member of the trusted group will operate the server.

DISCLAIMER

This work represents an endeavor to implement the functionality outlined above. It is still a work in progress and is not recommended for use unless you intend to help make improvements.

Usage

Run server.go on a server and connect to it with client.py. The client supports the following commands:

/quit                   Exit program
/connect    Connect to server
/disconnect             Disconnect from server
/who                    List users in room

/createid         Create identity and associated keys
/idexch           Exchange id keys
/genroomkey             Generate a secret key for the room
/reqroomkey             Request the secret key from the room
/sendroomkey      Send secret key for the room
/msg         Send private message

Todo

• Enable validation of TLSv1 cert by client
• User authentication
• Disallow unicode usernames
• Implement client in Go
• Encrypt deadchat.cfg file

Implementation

• deadchat is meant to run in a terminal (think IRC)
• Client to server communication is encrypted using TLSv1
• Authenticated encryption between clients is provided by libsodium
• Public key cryptography is used for private messaging and room secret key exchange
• Group chat is encrypted using secret key cryptography
• Keys are stored in deadchat.cfg

Client dependencies

• urwid
• libsodium
• pynacl

Server dependencies

• go.crypto.nacl

go get code.google.com/p/go.crypto/nacl
go install code.google.com/p/go.crypto/nacl/secretbox
go install code.google.com/p/go.crypto/nacl/box