ASP.NET Identity

🌟 What is ASP.NET Identity?

ASP.NET Identity is a membership system used in ASP.NET applications to manage:

• User registration
• Login/logout
• Roles and permissions
• Password management
• External logins (like Google, Facebook, Microsoft)

It helps you authenticate (verify who a user is) and authorize (check what a user is allowed to do).

🧠 Why Use ASP.NET Identity?

Without Identity, you’d have to:

• Create your own login system
• Securely store passwords
• Manage sessions and cookies
• Handle roles and permissions manually

ASP.NET Identity gives you all this out-of-the-box in a secure and extendable way.

📦 What Does It Include?

Here are the key components:

📚 Common Identity Tables in Database

When Identity is used with Entity Framework, it creates these tables:

🔐 How Does Identity Work?

Example: User Login Flow

1. User enters username and password
2. ASP.NET Identity:
   • Checks if the user exists
   • Hashes the entered password
   • Compares it to the stored hash
   • If matched, it signs the user in
3. It issues a cookie or JWT token to track the user

🛠️ Common Identity Code (Simplified)

Register a User

csharp

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var user = new IdentityUser { UserName = "john@example.com", Email = "john@example.com" };

var result = await _userManager.CreateAsync(user, "Password123!");

Login a User

csharp

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var result = await _signInManager.PasswordSignInAsync("john@example.com", "Password123!", isPersistent: false, lockoutOnFailure: false);

Add Role to User

csharp

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await _userManager.AddToRoleAsync(user, "Admin");

Check User’s Role

csharp

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if (await _userManager.IsInRoleAsync(user, "Admin")) {

    // do admin stuff

}

🔄 Can You Customize It?

Yes! You can:

• Add custom fields to users (e.g., PhoneNumber, Gender, ProfilePicture)
• Use custom tables
• Store data in SQL Server, MySQL, PostgreSQL, or even NoSQL stores

Example:

csharp

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public class AppUser : IdentityUser {

    public string FullName { get; set; }

    public DateTime DateOfBirth { get; set; }

}

🔗 External Logins Support

Identity allows login with providers like:

• Google
• Facebook
• Twitter
• Microsoft

csharp

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services.AddAuthentication()

   .AddGoogle(options => {

       options.ClientId = "...";

       options.ClientSecret = "...";

    });

🛡️ Security Features

• Password hashing: Never stores raw passwords
• Account lockout: Blocks brute-force login attempts
• Email confirmation: Verifies email addresses
• Two-factor authentication (2FA): Adds an extra login step
• Token-based actions: For password reset, email verification, etc.

✅ Summary

If you're using ASP.NET Core, everything is even more modular, and Identity can be integrated with JWT, Razor Pages, MVC, Blazor, or APIs.