Decentralized Cloud Storage

A blockchain-backed prototype for decentralized cloud storage — Solidity smart contracts that share encrypted file references with user-level access control, deployed with Hardhat on an Ethereum-compatible local chain.

Cloud storage trusts a single provider with your files; blockchain technology offers an alternative where file references, access control, and integrity records live on a tamper-resistant ledger. "Decentralized Secure Cloud Storage using Blockchain Technology" explores splitting files, storing them in blocks with AES-based file manipulation, and recording access grants on-chain using Ethereum smart contracts. This repository contains the Solidity + Hardhat side: a contract that associates storage references with addresses and lets owners allow/disallow other wallets, plus a deployment script for a local chain (chainId 1337). It is a research/education prototype for building privacy- and integrity-oriented storage systems.

• Upload.sol — stores an array of file-reference strings per user address
• allow — grant read access to another wallet
• disallow — revoke previously granted access
• display — access-checked retrieval of stored references (require(owner || granted) on-chain)
• shareAccess — view the current access-grant list
• Hardhat tooling — chainId 1337 local network, deploy script, artifacts routed to client/src/artifacts

Prerequisites: Node 16+, npm, Hardhat 2.x.

npm install
npx hardhat node                                # start local blockchain
npx hardhat run --network localhost scripts/deploy.js   # deploy Upload.sol

Note: the original project report references a React/web3 client, but the client source is not tracked in this repository — only the contract and deployment tooling. Contract artifacts are configured to write into client/src/artifacts (see hardhat.config.js).

• contracts/Upload.sol — the storage/access-control contract
• scripts/deploy.js — Hardhat deployment script
• hardhat.config.js — Solidity 0.8.9, local network chainId: 1337