BLOCKCHAIN-BASED CLOUD FILE SHARING SYSTEM

ABSTRACT

Cloud file storage and sharing systems have become indispensable for modern organizations and individual users, enabling remote access, collaboration, and efficient data management. However, conventional cloud storage models often suffer from security and privacy vulnerabilities, including unauthorized access, data tampering, and loss of control over sensitive information. This research presents a blockchain-based cloud file sharing system that leverages the decentralized and immutable nature of blockchain technology to enhance security, traceability, and control in cloud environments. The system allows users to upload, share, and manage files securely while maintaining end-to-end encryption and activity logs for accountability. Administrators can monitor user activity, detect tampered or fabricated files, and manage access permissions dynamically. Built using ASP.NET for backend development, HTML, CSS, and JavaScript for frontend, and MSSQL for database management, this system demonstrates how blockchain integration can address traditional cloud storage security concerns, providing a robust, user-friendly, and tamper-resistant platform for file sharing.

CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

Cloud file systems have revolutionized data storage by enabling users to create, read, modify, and share files over remote networks. Cloud file sharing services allow multiple users to access and collaborate on a common set of files. While these services improve accessibility and collaboration, they introduce significant security and privacy challenges. Users often relinquish control of their data when it is uploaded to cloud servers, exposing sensitive information to unauthorized access, tampering, or even complete loss.

Blockchain technology provides a decentralized, immutable framework that can enhance the security of cloud file sharing. By recording transactions in cryptographically linked blocks, blockchain ensures that every file action—such as upload, access, or modification—is permanently logged and traceable. This immutable record reduces the risk of tampering, supports accountability, and enables secure access management based on user roles and permissions.

The integration of blockchain with cloud storage enables users to share files confidently, as each interaction with the data is verifiable, and unauthorized actions can be detected in real time. This is especially critical for industries handling sensitive or confidential information, including finance, healthcare, and legal services.

1.2 Problem Statement

Despite the advantages of cloud storage, conventional systems face the following challenges:

1. Security Vulnerabilities: Centralized cloud storage is prone to hacking, unauthorized access, and data breaches.

2. Lack of Data Integrity: Files can be tampered with or altered without user knowledge, compromising reliability.

3. Limited Access Control: Conventional systems provide insufficient granularity for user permissions, making it difficult to enforce secure sharing policies.

4. Transparency and Traceability Issues: Users have limited visibility into who accesses or modifies their data.

These issues highlight the need for a secure, transparent, and traceable file sharing system that mitigates security risks while preserving usability.

1.3 Objectives of the Study

The main objective of this study is to develop a blockchain-based cloud file sharing system that enhances security, data integrity, and user control. Specific objectives include:

1. Designing a decentralized platform for secure file storage and sharing.

2. Implementing encryption and hash-based mechanisms to ensure data integrity.

3. Allowing users to manage access permissions dynamically, including granting or revoking access.

4. Providing comprehensive activity logs for monitoring file usage and detecting tampering.

5. Offering administrators the ability to oversee system operations, including user activity and feedback management.

1.4 System Architecture

The system consists of two main modules: User and Admin.

• User Module:
  Users can register, log in, and manage their profiles. They can upload, delete, and share files securely using blockchain-based encryption. Users can track their activity logs, view files shared with them, and monitor any tampered files. The system allows users to share files selectively based on attributes, roles, or authorization policies, ensuring privacy and controlled access.

• Admin Module:
  Administrators manage user accounts, monitor file activity, and access logs of all file interactions. They can detect tampered or fabricated files and review feedback submitted by users. The admin also ensures compliance with security protocols and manages system permissions.

Technologies Used:

• Frontend: HTML, CSS, JavaScript

• Backend: ASP.NET

• Database: MSSQL

• IDE: Visual Studio

1.5 Advantages of the System

1. Enhanced Security: Blockchain ensures all file transactions are immutable, tamper-resistant, and verifiable.

2. Data Integrity: Hash-based storage mechanisms allow users to confirm the originality of files.

3. Granular Access Control: Users can dynamically grant or revoke access to shared files.

4. Activity Monitoring: Detailed logs of uploads, downloads, and modifications increase accountability.

5. User-Friendly Interface: The system is easy to navigate and maintain, enhancing adoption.

SOFTWARE SYSTEM AVAILABLE. Language: Dotnet  Total Cost: US $58  CONTACT: +2347063990319.