ASP.NET Core Identity

ASP.NET Core Identity is a comprehensive, built-in API and framework for managing user authentication and authorization in modern ASP.NET Core applications. It provides a full-featured, out-of-the-box solution for handling user registration, login, password management, roles, claims, and more, all tightly integrated with the ASP.NET Core ecosystem.

Core Functionality & Features

ASP.NET Core Identity is designed to support common security requirements and best practices:

• User Management Provides APIs for creating, updating, and deleting user accounts, including handling personal data.

• Authentication Manages the process of verifying a user's identity, primarily through cookie-based authentication for web applications

• Authorization Enables developers to implement granular access control using roles (e.g., "Admin", "User") and claims (specific attributes about a user, like their email or a custom "FavoriteColor").

• Security Features Includes robust security measures like secure password hashing (using industry standards like PBKDF2), account lockout after failed attempts, email confirmation, and support for Two-Factor Authentication (2FA).

• External Login Providers Simplifies integration with third-party authentication providers such as Google, Facebook, Microsoft Account, and Twitter using OAuth or OpenID Connect protocols.

• Customization The system is highly extensible, allowing developers to customize the default user model and database schema, or even implement custom storage providers (e.g., for NoSQL databases) if needed.

• Built-in UI Offers scaffolded Razor Pages for common identity UIs like registration, login, and password recovery, which can be customized to match an application's design.

Architecture and Key Components

The architecture is split into high-level managers and low-level stores to ensure decoupling between business logic and data persistence.

• Managers (High-Level Classes) High-level classes like UserManager<TUser> and SignInManager<TUser> are used by application developers to perform user-related operations (e.g., CreateAsync(), SignInAsync(), IsInRole()).

  • UserManager: Handles core user operations like creating, deleting, and updating users.
  • RoleManager: Manages roles (e.g., Admin, Employee) and their associated permissions.
  • SignInManager: Manages the sign-in/out process, including generating authentication cookies or tokens.

• Stores (Low-Level Classes) These classes (e.g., UserStore, RoleStore) handle the interaction with the underlying data persistence mechanism, typically an EF Core database context (IdentityDbContext).

  • UserStore / RoleStore: Low-level classes that interact with the data access layer (typically Entity Framework Core) to persist user and role data.

• Data Entities By default, Identity provides a set of entity types that are mapped to database tables:

• IdentityUser: Represents the registered user.

• IdentityRole: Represents an authorization group.

• IdentityUserClaim: Represents individual statements about a user (e.g., "DateOfBirth"). IdentityUserClaim, IdentityRoleClaim: Store claims associated with users and roles

• IdentityUserLogin: Connects a user to external providers like Google.

• IdentityUserToken: Stores authentication tokens (e.g., for password resets or 2FA).

• IdentityUserRole: A join entity that links users to roles (many-to-many)

Implementation Basics

Register Services: In Program.cs, add Identity services using AddIdentity<TUser, TRole>() or AddDefaultIdentity<TUser>().

Configure Database: Inherit your DbContext from IdentityDbContext and use AddEntityFrameworkStores to link Identity to your DB.

Middleware: Use app.UseAuthentication() and app.UseAuthorization() in the correct order (after routing, before mapping endpoints) to enforce security checks.