ValueCentric – Blockchain-Based Supply Chain Traceability System

ValueCentric is a blockchain-powered supply chain management system designed to provide end-to-end product traceability, authenticity verification, and secure ownership transfer among supply chain participants.
Every product is represented as a unique ERC-721 NFT, ensuring tamper-proof records, role-based control, and transparent audit logs across the entire lifecycle of the product.

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🚀 Key Features

🔐 1. Role-Based Access Control

The platform defines four major roles with distinct permissions:

• Manufacturer – Registers products and initiates ownership transfers
• Distributor – Requests purchases and receives product ownership
• Retailer – Requests goods from distributors
• Regulator – Monitors, audits, and triggers product recalls

Role restrictions are enforced at the smart-contract level to ensure integrity and compliance.

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🛠️ 2. Product Registration (NFT Minting)

Manufacturers can register products/batches.
Each registration:

• Mints a unique ERC-721 token
• Assigns metadata such as:
  • Product Name
  • Batch ID
  • Manufacture Date
  • Expiry Date
  • Quantity
  • Price

This establishes a verifiable on-chain identity for every product.

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🔄 3. Secure Ownership Transfer Workflow

The system supports a structured transfer model:

1. Buyer initiates a buy request
2. Current owner reviews and approves
3. Ownership is transferred via ERC-721 token transfer
4. Transfer events are logged immutably

This prevents unauthorized, unapproved, or duplicate transfers.

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🧾 4. Tamper-Proof Audit Trails

Every major action emits blockchain events:

• Product registration
• Buy request creation
• Transfer approval
• Ownership transfer
• Price updates
• Recall actions

This ensures complete visibility for regulators and auditors.

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❗ 5. On-Chain Product Recall

Regulators can flag a product as recalled.
Once recalled:

• Ownership transfer is blocked
• Product is marked as unsafe
• All nodes see the recall event immediately

This prevents the distribution of defective or harmful goods.

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🖥️ 6. Web DApp Interface

The React-based DApp provides:

• Clean UI
• Role-specific dashboards
• Real-time updates via Web3.js / Ethers.js
• Easy interaction with smart contracts deployed on Ganache

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📦 Tech Stack

Smart Contracts

• Solidity
• ERC-721 (OpenZeppelin)
• Events for logging
• Custom role-based modifiers

Frontend

• HTML

Blockchain Environment

• Ganache (Local Test Blockchain)
• Truffle / Hardhat (Compiling, Migrating, Testing)
• MetaMask Wallet

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