Supply Chain on Blockchain

Track and trace, provenance, logistics, and supply chain transparency.

Overview

Blockchain provides transparent, immutable supply chain records.

Supply Chain Contract

contract SupplyChain {
    struct Product {
        string name;
        address manufacturer;
        address currentOwner;
        uint256 timestamp;
        string location;
    }
    
    mapping(uint256 => Product) public products;
    mapping(uint256 => Product[]) public history;
    
    function createProduct(uint256 id, string calldata name) public {
        products[id] = Product(
            name,
            msg.sender,
            msg.sender,
            block.timestamp,
            ""
        );
    }
    
    function transfer(uint256 id, address to, string calldata location) public {
        require(products[id].currentOwner == msg.sender);
        
        history[id].push(products[id]);
        
        products[id].currentOwner = to;
        products[id].timestamp = block.timestamp;
        products[id].location = location;
    }
}

Provenance Tracking

class ProvenanceTracker:
    def __init__(self):
        self.product_id = None
        self.origin = None
        self.journey = []
    
    def add_checkpoint(self, location, handler, timestamp):
        self.journey.append({
            "location": location,
            "handler": handler,
            "timestamp": timestamp,
            "verified": True
        })
    
    def get_full_journey(self):
        return self.journey

Use Cases

Benefits

1. Transparency — All participants see data
2. Immutability — Cannot alter records
3. Efficiency — Automated verification
4. Trust — Verified provenance

Practice

Build a supply chain tracking system for food products.