Secure File Transfer Protocol (SFTP-CPP) Instructions

This project implements a secure file transfer system using C++ and OpenSSL. It features a specific custom protocol over TLS 1.3 with AES encryption.

Prerequisites

• Linux Environment
• g++ (supporting C++17) or cmake
• openssl installed (libssl-dev)

Installation & Build

1. Navigate to the project directory:

   cd /path/to/file/SFTP-CPP

2. Generate SSL Certificates: You must generate the keys and certificates for the secure connection to work.

   cd certs
   bash gen_certs.sh
   cd ..

3. Compile the Project: Running the following command will build both the Server and the Client.

   g++ -std=c++17 -I include src/server/main.cpp src/server/server.cpp src/common/ssl_wrapper.cpp src/common/utils.cpp -o sftp_server -lssl -lcrypto -lpthread
   
   g++ -std=c++17 -I include src/client/main.cpp src/client/client.cpp src/common/ssl_wrapper.cpp src/common/utils.cpp -o sftp_client -lssl -lcrypto -lpthread

Usage

1. Start the Server

The server handles file storage and connections.

./sftp_server

The server will create a server_storage directory automatically.

2. Start the Client

Open a new terminal.

./sftp_client [ServerIP]

If running locally, you can just run:

./sftp_client

3. Using the Client

The client features an interactive menu:

• List Remote Files: Shows files currently stored on the server.
• Upload File: Enter the path to a local file (e.g., ./docs/myfile.txt) to upload it securely. You will see a progress bar.
• Download File: Enter the name of a file on the server to download it to your current directory.
• Exit: Close the connection.

Security Features

• TLS 1.3: All communication is encrypted using modern TLS standards.
• AES Encryption: Data privacy is ensured via the cipher suites negotiated by OpenSSL.
• Certificate Pinning: The client uses the generated CA certificate to verify the server's identity.

Troubleshooting

• Connection Failed: Ensure the server is running and the certificates were generated correctly in certs/keys/.
• Permission Denied: Ensure you have read/write permissions in the directory.