👋 Hello, Devs!

In today's post, we're diving into the crucial concepts of Authentication and Authorization. These terms are often used interchangeably but they serve different purposes in the security realm. Let’s break it down!

🔐 Authentication: Who Are You?

Authentication is the process of verifying the identity of a user or entity. Think of it as the gatekeeper asking, "Who are you?" Here are some common methods:

• Username and Password: The most common method.
• Two-Factor Authentication (2FA): Adds an extra layer of security.
• Biometric Verification: Uses fingerprints, facial recognition, etc.
• OAuth: Allows users to log in using another service (like Google, Facebook).

🛂 Authorization: What Are You Allowed to Do?

Authorization determines what resources a user can access. It happens after authentication. Think of it as the gatekeeper saying, "Okay, you’re in. Now, what can you do?"

• Role-Based Access Control (RBAC): Permissions are assigned to roles, and users are assigned roles.
• Attribute-Based Access Control (ABAC): Permissions are based on attributes (e.g., time of day, location).
• Access Control Lists (ACLs): Lists that tell what permissions each user has.

🛠️ Implementing Authentication in Code

Here’s a quick example using Node.js with Express and Passport.js:

const express = require('express');
const passport = require('passport');
const LocalStrategy = require('passport-local').Strategy;

passport.use(new LocalStrategy(
  function(username, password, done) {
    User.findOne({ username: username }, function (err, user) {
      if (err) { return done(err); }
      if (!user) { return done(null, false); }
      if (!user.verifyPassword(password)) { return done(null, false); }
      return done(null, user);
    });
  }
));

const app = express();
app.use(require('body-parser').urlencoded({ extended: true }));
app.use(passport.initialize());

app.post('/login', passport.authenticate('local', { 
  successRedirect: '/',
  failureRedirect: '/login'
}));

🔧 Implementing Authorization in Code

Here's an example of RBAC in Express.js:

const roles = {
  admin: ['create', 'read', 'update', 'delete'],
  user: ['read']
};

function authorize(role, action) {
  return (req, res, next) => {
    if (roles[role].includes(action)) {
      next();
    } else {
      res.status(403).send('Forbidden');
    }
  };
}

app.get('/admin', authorize('admin', 'read'), (req, res) => {
  res.send('Admin Content');
});

app.get('/user', authorize('user', 'read'), (req, res) => {
  res.send('User Content');
});

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