🛒 Decentralized Ecommerce Review System

A blockchain-powered platform that reimagines product reviews in e-commerce by ensuring authenticity, transparency, immutability, and privacy. Built as part of a Master's thesis project at the University of Salerno, this system empowers users to publish trustworthy reviews without compromising their identity, and guarantees fairness in reputation and incentives without relying on centralized control.

---

📌 Introduction

In today's e-commerce landscape, fake reviews, vote manipulation and vendor interference are common. This project provides a decentralized alternative by leveraging blockchain and privacy-enhancing technologies to ensure:

• Only real buyers can write reviews.
• Reviews are tamper-proof and publicly auditable.
• User identities remain pseudonymous, while all actions are cryptographically verifiable.
• Reputation and rewards are computed objectively, without upvotes or platform interference.

---

🔧 How It Works

The system combines several cutting-edge Web3 technologies:

• 🧩 Ethereum Smart Contracts: Record review actions immutably on-chain.
• 🆔 Decentralized Identifiers (DIDs): Give users pseudo-anonymous, cryptographically verifiable identities.
• 🪪 Verifiable Credentials (VCs): Attest user registration and uniqueness without disclosing personal information.
• 🪙 Soulbound NFTs: Non-transferable tokens act as cryptographic proof-of-purchase for review eligibility.
• 🔐 Zero-Knowledge Proofs (ZKPs): Allow users to prove reputation or rights without revealing their identity.
• 🗃️ IPFS: Used for off-chain storage of review content and revocation lists.
• ⚖️ Smart Incentives: Rewards are granted upon purchase, and reputational impact is determined by whether the user reviews the product within a 60-day window.

---

🧰 Tech Stack

	Technologies Used
Blockchain	Ethereum (Ganache for local testing)
Identity	ethr-did, did-jwt-vc, MetaMask
Smart Contracts	Solidity with Hardhat
Off-chain	IPFS, CID-based referencing
Cryptography	EdDSA signatures, ZKP, Selective Disclosure with BBS+ Signatures
Frontend	JavaScript, Three.js, Web3.js, MetaMask integration

---

📁 Repository Structure

📦 Decentralized-Ecommerce Review System
├── code/contracts                                  # Solidity smart contracts
├── code/scripts                                    # Scripts to automate deploy and testing
├── code/frontend                                   # Web frontend with Web3 integration
├── Decentralized-Ecommerce-reverseEkans-latex/     # LaTeX documentation about the project
├── Decentralized-Ecommerce-reverseEkans.pdf        # PDF render file for LaTeX
├── LICENSE                                         # License for the project
└── README.md                                       # Introductionary doc

---

✅ TO DO: Future Evolutions

• SPID / EUDI Wallet integration for government-issued digital identity credentials
• Web-DApp
• Mobile-friendly DApp (probably Flutter)
• DAO governance module for decentralized policy updates
• ZKP-based reputation visualization that protects anonymity
• Marketplace plugin API to integrate with platforms like Shopify or WooCommerce
• Gamification: badges, reviewer streaks, reward levels

---

📜 License

© 2025 Emanuele Relmi

This project is licensed under the Apache License 2.0.

All custom images (except logo unisa) are © 2025 Emanuele Relmi and licensed under Apache License 2.0.

NOTICE

This project includes third-party software:

• Semaphore Protocol (MIT License)

The files used are:

• code/contracts/SemaphoreVerifier.sol
• code/contracts/SemaphoreVerifierKeyPts.sol
• code/contracts/Contract.sol
• code/contracts/SemaphoreGroups.sol

These components are distributed under their respective licenses and are not covered by the Apache License 2.0 that governs this project

---

👤 Authors

• Emanuele Relmi
• Francesco Quagliuolo
• Giuseppe Alfonso Mangiola