SecureMessenger

A secure messaging application with client-server architecture using encryption for private communications.

Features

• End-to-end encryption using SSL/TLS
• User registration with unique usernames
• Real-time chat between online users
• Colorful interactive CLI interface
• Message history tracking
• Notifications for new messages
• Multi-user support

Prerequisites

• C++17 compatible compiler
• CMake (version 3.10 or higher)
• Boost library (with system component)
• OpenSSL library

Building the Application

1. Clone this repository
2. Make sure you have the prerequisites installed
3. Build using the provided Makefile:

make build

This will:

• Create a build directory
• Configure CMake
• Compile both the server and client applications

SSL Certificate Generation

Before running the server, you need to generate SSL certificates:

make generate_certs

This command creates:

• server.key - Private key for the server
• server.crt - Self-signed certificate for SSL encryption

Running the Application

Starting the Server

make run_server

Or manually:

./build/server [port]

The default port is 8443 if not specified.

Starting the Client

make run_client  # Connects to localhost:8443

Or specify a custom server:

make client ip=192.168.1.100 port=8443

Or manually:

./build/client <server_ip> <port>

Using the Application

1. Start the server first
2. Launch the client and enter your username
3. Select a user to chat with from the list of online users
4. Send messages by typing and pressing Enter
5. Type /back to return to the user selection screen

Implementation Details

• Uses Boost.Asio for asynchronous networking
• OpenSSL for secure communication
• JSON for message serialization
• Multi-threaded design for responsive UI

Commands in Chat

• /back - Return to user selection
• Press Enter on an empty message to refresh the chat

Clean Up

Stop the server and clean the build files:

make stop_server
make clean