Designing Authentication Workflows

1. Introduction

Authentication workflows are essential for securing applications, ensuring that users can access only the information and functionalities they are authorized to use. This lesson covers the design of effective authentication workflows in back-end development.

2. Key Concepts

• Authentication: The process of verifying the identity of a user or system.
• Authorization: The process of determining whether a user has permission to perform a specific action.
• Session Management: The handling of user sessions, including session creation, maintenance, and termination.
• Tokens: A string of characters used to authenticate requests, often in the form of JWT (JSON Web Tokens).

3. Step-by-Step Process

1. Define the authentication flow:

Identify how users will authenticate (e.g., username/password, OAuth, etc.).

2. Implement user registration:

Create an endpoint for users to register, validate input, and store user credentials securely.

3. Set up login functionality:

Authenticate users using their credentials and generate tokens for authorized sessions.

4. Implement session management:

Manage user sessions, including token expiration and refresh mechanisms.

5. Ensure secure data handling:

Use HTTPS and secure storage for sensitive data (e.g., passwords).

4. Best Practices

• Use strong password policies (minimum length, complexity).
• Implement multi-factor authentication (MFA) where applicable.
• Regularly review and update authentication libraries and frameworks.
• Log authentication attempts for monitoring and auditing purposes.

5. Code Examples

5.1 User Registration Example

app.post('/register', async (req, res) => {
    const { username, password } = req.body;
    const hashedPassword = await bcrypt.hash(password, 10);
    // Store user in database
    await User.create({ username, password: hashedPassword });
    res.status(201).send('User registered!');
});

5.2 User Login Example

app.post('/login', async (req, res) => {
    const { username, password } = req.body;
    const user = await User.findOne({ username });
    if (user && await bcrypt.compare(password, user.password)) {
        const token = jwt.sign({ id: user._id }, process.env.JWT_SECRET, { expiresIn: '1h' });
        res.json({ token });
    } else {
        res.status(401).send('Invalid credentials');
    }
});

6. FAQ