Integrating Multi-Factor Authentication

2.1 Definitions

• Multi-Factor Authentication (MFA): A security mechanism that requires two or more verification factors to gain access to a resource.
• Authentication Factors: Typically fall into three categories - something you know (password), something you have (a smartphone), and something you are (biometrics).

3.1 Step-by-Step Guide

1. Choose an MFA provider (e.g., Twilio, Authy, Google Authenticator).
2. Integrate the MFA provider's SDK into your front-end application.
3. Allow users to register for MFA by providing their phone number or email.
4. During login, prompt for the second factor after entering the password.
5. Verify the second factor with the MFA provider.
6. Grant access if both factors are verified successfully.

3.2.1 Example with Firebase Authentication

import firebase from 'firebase/app';
import 'firebase/auth';

// Initialize Firebase
const firebaseConfig = {
    apiKey: "YOUR_API_KEY",
    authDomain: "YOUR_PROJECT_ID.firebaseapp.com",
    // ... other config
};
firebase.initializeApp(firebaseConfig);

// Function to send a verification code
const sendVerificationCode = (phoneNumber) => {
    const appVerifier = new firebase.auth.RecaptchaVerifier('recaptcha-container');
    firebase.auth().signInWithPhoneNumber(phoneNumber, appVerifier)
        .then((confirmationResult) => {
            // SMS sent. Prompt user to enter the code.
            const code = window.prompt('Enter the verification code you received:');
            return confirmationResult.confirm(code);
        })
        .then((result) => {
            // User signed in successfully.
            const user = result.user;
            console.log('User signed in: ', user);
        })
        .catch((error) => {
            console.error('Error during verification: ', error);
        });
};