Evidence Blockchain (EVID-BC)

A blockchain-based evidence management system deployed on Avalanche C-Chain.

Overview

This application allows users to securely file complaints and store evidence on the blockchain. It uses:

• Backend: Node.js with Express
• Database: MongoDB
• Blockchain: Avalanche C-Chain
• Storage: IPFS via Pinata

Features

• User authentication and authorization
• Secure complaint filing
• Evidence storage on IPFS
• Blockchain verification using Avalanche C-Chain
• Immutable record keeping

Prerequisites

• Node.js (v14 or higher)
• MongoDB
• Avalanche C-Chain wallet with AVAX
• Pinata API keys for IPFS storage

Installation

1. Clone the repository

git clone <repository-url>
cd evid-bc

2. Install dependencies

npm install

3. Configure environment variables

Create a .env file in the root directory with the following variables:

MONGO_URI=your_mongodb_connection_string
JWT_SECRET=your_jwt_secret
RPC_URL=https://api.avax-test.network/ext/bc/C/rpc
PRIVATE_KEY=your_wallet_private_key
CONTRACT_ADDRESS=your_deployed_contract_address
PINATA_API_KEY=your_pinata_api_key
PINATA_API_SECRET=your_pinata_api_secret

Avalanche Deployment

This project is configured for deployment on the Avalanche C-Chain. For detailed deployment instructions, see AVALANCHE_DEPLOYMENT.md.

Quick Deployment

To deploy the smart contract to Avalanche:

npm run deploy:avalanche

This will:

1. Compile and deploy the ComplaintRegistry contract
2. Update your .env file with the new contract address

Running the Application

# Development mode
npm run dev

# Production mode
npm start

The server will start on http://localhost:3000 (or the port specified in your environment).

API Endpoints

Authentication

• POST /api/auth/register - Register a new user
• POST /api/auth/login - Login and get JWT token

Complaints

• POST /api/complaints - File a new complaint
• GET /api/complaints - Get all complaints
• GET /api/complaints/:id - Get a specific complaint

Smart Contract

The ComplaintRegistry smart contract is deployed on the Avalanche C-Chain and provides the following functions:

• addComplaint(string _id, string _user, string _hash) - Add a new complaint
• getComplaint(uint index) - Get complaint details by index
• totalComplaints() - Get the total number of complaints

Blockchain Utilities

The application includes utilities for interacting with the Avalanche blockchain:

• executeTransaction() - Handles transaction execution with fallback mechanisms
• getSafeGasPrice() - Gets optimal gas prices for Avalanche

License

ISC