Adding Password Hashing and JWT Token in Mern App

When building a Mern (MongoDB, Express.js, React, Node.js) application, it’s important to secure user authentication and ensure that sensitive information, such as passwords, are stored and transmitted securely. In this article, we will explore how to add password hashing and JWT (JSON Web Token) authentication to a Mern stack application.

Step 1: Install Dependencies

First, we need to install the necessary packages for password hashing and JWT token generation in our Node.js backend. We can use libraries like bcrypt for password hashing and jsonwebtoken for JWT token handling.


npm install bcrypt jsonwebtoken


Step 2: Implement Password Hashing

Once the dependencies are installed, we can implement password hashing in our user authentication logic. When a new user signs up or changes their password, we will hash the password using bcrypt before storing it in the database.

    const bcrypt = require('bcrypt');

    // Hashing the password before saving it to the database
    const hashPassword = async (password) => {
      const saltRounds = 10;
      const hashedPassword = await bcrypt.hash(password, saltRounds);
      return hashedPassword;
    }
  

Step 3: Generate and Verify JWT Token

Next, we need to implement JWT token generation and verification for user authentication. When a user successfully logs in, we will generate a JWT token containing the user’s information and send it back to the client. For subsequent requests, the client will send this token, and we will verify it in our backend to authenticate the user.

    const jwt = require('jsonwebtoken');

    // Generate JWT token
    const generateToken = (user) => {
      const token = jwt.sign({ id: user._id, email: user.email }, 'secret', { expiresIn: '1h' });
      return token;
    }

    // Verify JWT token
    const verifyToken = (token) => {
      try {
        const decoded = jwt.verify(token, 'secret');
        return decoded;
      } catch (error) {
        return null;
      }
    }
  

Step 4: Integrate with Mern App

Finally, we need to integrate the password hashing and JWT token logic with our Mern stack application. We will update the user authentication endpoints to use password hashing for storing passwords and JWT token for user authentication.

With these steps, we have successfully added password hashing and JWT token authentication to our Mern stack application, ensuring secure user authentication and data protection.