Decentralized File Storage System

This project is a web-based decentralized file storage system built on blockchain technology, allowing users to upload, store, and download files securely. It ensures data integrity through blockchain's tamper-proof structure by embedding uploaded files, user details, and file metadata (such as file size) into blocks within the chain. The application is designed to prevent unauthorized modifications or deletions of files once they are added to the blockchain, making it highly secure and resilient against corruption.

The blockchain system in this project employs a proof of work (PoW) consensus mechanism to validate new blocks. Each time a file is uploaded, the system initiates a cryptographic puzzle that miners (peers in the network) must solve. Only after solving the puzzle can a new block be added to the chain. The puzzle requires finding a hash value that begins with a certain number of leading zeros, ensuring that block creation requires computational effort and adds a layer of security.

The project compares two distinct PoW algorithms: one that uses a random nonce to solve the puzzle and another that increments the nonce sequentially. Based on the results, the random nonce approach proves more efficient at higher difficulty levels, offering a better balance between speed and security.

The application demonstrates blockchain's advantages for secure file storage, emphasizing its decentralized and tamper-proof characteristics. It also highlights the strengths and trade-offs between different proof of work approaches, concluding that the random nonce approach is more effective for this use case. Overall, this project showcases blockchain's potential for creating secure, decentralized systems for data storage and distribution.