Secure File Sharing

Table of Contents

1. Introduction
2. Requirements
3. Dependencies
4. Installation Instructions
5. Project Overview
   • Low-Level Sockets Programming
   • Cryptographic Principles
   • Concurrent Server and Database
   • Secure Key Distribution and Encrypted File Transfer
6. Security Protocols
   • Key Distribution
   • File Encryption and Integrity Verification
7. Usage
8. Contributors
9. License

Introduction

This project demonstrates a secure file-sharing system implemented in Python. It covers various topics such as low-level socket programming, cryptographic principles, concurrent server architecture, and secure key distribution. The project aims to provide a comprehensive learning experience for those interested in secure communication and file transfer.

Requirements

• Python 3
  • Download Python 3

Dependencies:

Install the following Python libraries using pip:

• pip install cryptography
• pip install pycryptodome
• pip install pysqlite3
• pip install tqdm
• pip install prettytable
• pip install bcrypt

Installation Instructions

Clone the project to your local machine using Git.

git clone https://github.com/NickPrivate/Secure-File-Sharing

Project Overview

Low-Level Sockets Programming

This project involves both the indexing server and Peer-to-Peer (P2P) file transfer using Python sockets. The implementation covers:

• Establishing TCP connections
• Handling multiple connections concurrently using threading
• Custom protocols for file transfer and communication

Cryptographic Principles

The project incorporates several cryptographic techniques to ensure secure file transfer:

• Asymmetric Encryption (RSA): Used for encrypting the AES key and verifying digital signatures.
• Symmetric Encryption (AES): Used for encrypting the file contents.
• Digital Signature (RSA/DSA): Used for verifying the integrity and authenticity of the transferred files.

Concurrent Server and Database

The indexing server is designed to handle multiple peer connections simultaneously. It uses:

• SQLite for managing file metadata and user information.
• Threading for handling concurrent connections and database operations.

Secure Key Distribution and Encrypted File Transfer

The project implements a secure key distribution mechanism and encrypted file transfer protocol:

• Key Distribution: AES key and nonce are encrypted with the receiver's RSA public key.
• File Encryption: The file is encrypted using AES.
• File Transfer: Custom socket protocols are used for transmitting the encrypted file and keys.

Security Protocols

Key Distribution

1. Initial Key Exchange:
   • Sender and receiver exchange their public RSA/DSA keys.
2. AES Key Generation:
   • The sender generates an AES key and a nonce.
3. Encryption of AES Key:
   • The AES key and nonce are encrypted using the receiver's public RSA key.
4. Transmission:
   • The encrypted AES key and nonce are sent to the receiver.
5. Decryption:
   • The receiver decrypts the AES key and nonce using their private RSA key.

File Encryption and Integrity Verification

1. File Encryption:
   • The file is encrypted using the AES key and nonce.
2. Digital Signature:
   • The sender generates an RSA/DSA signature for the encrypted file.
3. Transmission:
   • The encrypted file and signature are sent to the receiver.
4. Decryption:
   • The receiver decrypts the file using the AES key.
5. Integrity Verification:
   • The receiver verifies the file's integrity using the RSA/DSA signature. If verification fails, the download is canceled; if it succeeds, the file is downloaded.

Usage

1. Start the Indexing Server:
   • Navigate to the Server directory and run server.py

   cd src/Server
   python server.py

2. Start User 1 (sender):
   • Navigate to user1 inside the test directory and run client.py

   cd test/user1
   python client.py

3. Start User 2 (receiver):
   • Navigate to user2 inside the test directory and run client.py

   cd test/user2
   python client.py
   

Contributors

• Katherine Joy Guardiano - Architecture Design
• Allen Dai - Tools and Project Testing
• Andy Huynh - Security Protocol Designer
• Nick Goulart - Implementation and Key Distribution
• Dylan Zuniga - Database Modeling and Queries

License

This project is licensed under the MIT License - see the LICENSE file for details.