Unlocking the Power of Blockchain with Seamless Authentication

What is Blockchain?

Blockchain is more than just a buzzword – it’s a distributed database that stores information electronically in digital format. This technology has been widely adopted due to its ability to guarantee the truthfulness and security of data records. Blockchains are best known for their role in cryptocurrency systems, where they maintain a secure and decentralized record of transactions. In this article, we’ll focus on Ethereum, a popular open-source blockchain with smart contract functionality.

Introducing Magic and Magic Auth

Magic is a renowned provider of seamless authentication solutions for web applications. Their Magic Auth product enables passwordless Web2 and Web3 onboarding and authentication using magic links. With support for over 20 blockchains and integration capabilities with just a few lines of code, Magic Auth is a game-changer for developers.

Understanding web3.js

web3.js is a collection of libraries that allow you to interact with a local or remote Ethereum node using HTTP, IPC, or WebSocket. This library enables developers to interact with the Ethereum blockchain using JavaScript, making it a crucial tool for building blockchain-based applications.

Setting Up Magic and web3.js

To get started with Magic on the Ethereum blockchain, you’ll need to create a new directory, initialize a Node.js project, and install the web3.js library and Magic SDK. Here’s a step-by-step guide:

mkdir magic-auth-example
cd magic-auth-example
npm init -y
npm install web3.js @magic-sdk/core

Writing and Compiling Smart Contracts

Smart contracts are programs stored on a blockchain that run when predetermined conditions are met. Here’s an example of a basic “Hello, World!” smart contract:

pragma solidity ^0.8.0;

contract HelloWorld {
    string public message;

    constructor() {
        message = "Hello, World!";
    }

    function updateMessage(string memory newMessage) public {
        message = newMessage;
    }
}

To compile this contract, you can use the Solidity compiler:

solcjs --bin --abi HelloWorld.sol

Authenticating Users with Magic Auth

Magic Auth creates an Ethereum public address for all authenticated users, which can be used to authenticate users. Here’s an example of how to integrate Magic with your application:

import { Magic } from '@magic-sdk/core';

const magic = new Magic('YOUR_MAGIC_API_KEY');

// Login with Magic
magic.auth.loginWithMagicLink({
  email: '[email protected]',
  showUI: true,
});

// Get the user's Ethereum public address
const userAddress = magic.user.getPublicKey().then((address) => {
  console.log(`User authenticated with address: ${address}`);
});

Writing to the Blockchain

Once users are logged in, they can interact with the blockchain through Magic. Here’s an example of how to update the message property in a smart contract by writing to the blockchain:

import Web3 from 'web3';

const web3 = new Web3(new Web3.providers.HttpProvider('undefinednet.infura.io/v3/YOUR_INFURA_PROJECT_ID'));

// Update the message property in the smart contract
web3.eth.accounts.signTransaction({
  from: userAddress,
  to: '0x...ContractAddress...',
  data: '0x...updateMessageData...',
}, '0x...privateKey...')
.on('transactionHash', (hash) => {
  console.log(`Transaction hash: ${hash}`);
})
.on('confirmation', (confirmationNumber, receipt) => {
  console.log(`Confirmation number: ${confirmationNumber}`);
  console.log(`Transaction receipt: ${receipt}`);
});