Exchatge - a secured message exchanger (desktop client)

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The purpose of this project is to easily exchange messages via binary protocol using an encrypted communication channel in the realtime. Each client-to-server connection is encrypted, each client-to-client connection is also encrypted. All messages go through server, but because of presence of the second layer of encryption between clients, any interception of messages by the server or anyone else is useless. File exchange is supported.

Project is created for Linux x86_64 desktop platforms (PCs).

Key features:

• Double end-to-end encryption (each connection between client and server is encrypted, as well as the each conversation channel between 2 clients),
• Encrypted file exchanging via binary protocol,
• Authentication and authorization (each client has login and password, ephemeral token based protection),
• User roles (one admin and $(MAX_USERS_COUNT - 1) users),
• Asynchronous execution,
• Missing messages fetching,
• Graphical user interface,
• Human-readable options file,
• Multiple active simultaneous connections,
• Digital signatures checking between clients and server,
• Broadcasting (only one layer of encryption - between client and server, from admin to all others),
• Instant messages delivery,
• Different languages support.

Dependencies

Client side is written entirely in C (C11, with GNU extensions).

Build is performed via GNU Make or via Ninja with help of CMake build system generator. Compilation is performed via CLang.

Client side uses the following libraries:

• SDL2;
• SDL2Net;
• LibSodium;
• Nuklear;
• SQLite3;
• GNU C Library (GLIBC) - therefore project targets Linux systems.

The project is currently in Beta

The server
Android client

Screenshots

Build

For convenience, build is performed automatically via shell scripts. Execute the following commands to download & build dependencies, then, to extract the executable & it's libraries, and finally, to run the executable itself:

# build
chmod +x buildDependencies.sh && ./buildDependencies.sh
mkdir build && (cd build; cmake .. && make)
# test
(cd build; ctest tests)
# prepare to run
chmod +x extract.sh && ./extract.sh
patchelf --set-rpath '$ORIGIN' extracted/ExchatgeDesktopClient
# run
(cd extracted; ./ExchatgeDesktopClient)

Documentation

TODO