Introduction to Identity on ASP.NET Core

By Rick Anderson

ASP.NET Core Identity:

• Is an API that supports user interface (UI) login functionality.
• Manages users, passwords, profile data, roles, claims, tokens, email confirmation, and more.

Users can create an account with the login information stored in Identity or they can use an external login provider. Supported external login providers include Facebook, Google, Microsoft Account, and Twitter.

For information on how to globally require all users to be authenticated, see Require authenticated users.

The Identity source code is available on GitHub. Scaffold Identity and view the generated files to review the template interaction with Identity.

Identity is typically configured using a SQL Server database to store user names, passwords, and profile data. Alternatively, another persistent store can be used, for example, Azure Table Storage.

In this topic, you learn how to use Identity to register, log in, and log out a user. Note: the templates treat username and email as the same for users. For more detailed instructions about creating apps that use Identity, see Next Steps.

ASP.NET Core Identity isn't related to the Microsoft identity platform. Microsoft identity platform is:

• An evolution of the Azure Active Directory (Azure AD) developer platform.
• An alternative identity solution for authentication and authorization in ASP.NET Core apps.

ASP.NET Core Identity adds user interface (UI) login functionality to ASP.NET Core web apps. To secure web APIs and SPAs, use one of the following:

• Microsoft Entra ID
• Azure Active Directory B2C (Azure AD B2C)
• Duende Identity Server

Duende Identity Server is an OpenID Connect and OAuth 2.0 framework for ASP.NET Core. Duende Identity Server enables the following security features:

• Authentication as a Service (AaaS)
• Single sign-on/off (SSO) over multiple application types
• Access control for APIs
• Federation Gateway

Important

Duende Software might require you to pay a license fee for production use of Duende Identity Server. For more information, see Migrate from ASP.NET Core 5.0 to 6.0.

For more information, see the Duende Identity Server documentation (Duende Software website).

View or download the sample code (how to download).

Create a Web app with authentication

Create an ASP.NET Core Web Application project with Individual User Accounts.

Visual Studio

• Select the ASP.NET Core Web App template. Name the project WebApp1 to have the same namespace as the project download. Click OK.
• In the Authentication type input, select Individual User Accounts.

.NET CLI

dotnet new webapp --auth Individual -o WebApp1

The preceding command creates a Razor web app using SQLite. To create the web app with LocalDB, run the following command:

dotnet new webapp --auth Individual -uld -o WebApp1

The generated project provides ASP.NET Core Identity as a Razor class library. The Identity Razor class library exposes endpoints with the Identity area. For example:

• /Identity/Account/Login
• /Identity/Account/Logout
• /Identity/Account/Manage

Apply migrations

Apply the migrations to initialize the database.

Visual Studio

Run the following command in the Package Manager Console (PMC):

Update-Database

.NET CLI

Migrations are not necessary at this step when using SQLite.

If dotnet ef has not been installed, install it as a global tool:

  dotnet tool install --global dotnet-ef

For more information on the CLI for EF Core, see EF Core tools reference for the .NET CLI.

Note

By default the architecture of the .NET binaries to install represents the currently running OS architecture. To specify a different OS architecture, see dotnet tool install, --arch option. For more information, see GitHub issue dotnet/AspNetCore.Docs #29262.

For LocalDB, run the following command:

dotnet ef database update

Test Register and Login

Run the app and register a user. Depending on your screen size, you might need to select the navigation toggle button to see the Register and Login links.

View the Identity database

Visual Studio

• From the View menu, select SQL Server Object Explorer (SSOX).
• Navigate to (localdb)MSSQLLocalDB(SQL Server 13). Right-click on dbo.AspNetUsers > View Data:

.NET CLI

There are many third party tools you can download to manage and view a SQLite database, for example DB Browser for SQLite.

Configure Identity services

Services are added in Program.cs. The typical pattern is to call methods in the following order:

1. Add{Service}
2. builder.Services.Configure{Service}

using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using WebApp1.Data;

var builder = WebApplication.CreateBuilder(args);

var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");
builder.Services.AddDbContext<ApplicationDbContext>(options =>
    options.UseSqlServer(connectionString));
builder.Services.AddDatabaseDeveloperPageExceptionFilter();

builder.Services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
    .AddEntityFrameworkStores<ApplicationDbContext>();
builder.Services.AddRazorPages();

builder.Services.Configure<IdentityOptions>(options =>
{
    // Password settings.
    options.Password.RequireDigit = true;
    options.Password.RequireLowercase = true;
    options.Password.RequireNonAlphanumeric = true;
    options.Password.RequireUppercase = true;
    options.Password.RequiredLength = 6;
    options.Password.RequiredUniqueChars = 1;

    // Lockout settings.
    options.Lockout.DefaultLockoutTimeSpan = TimeSpan.FromMinutes(5);
    options.Lockout.MaxFailedAccessAttempts = 5;
    options.Lockout.AllowedForNewUsers = true;

    // User settings.
    options.User.AllowedUserNameCharacters =
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._@+";
    options.User.RequireUniqueEmail = false;
});

builder.Services.ConfigureApplicationCookie(options =>
{
    // Cookie settings
    options.Cookie.HttpOnly = true;
    options.ExpireTimeSpan = TimeSpan.FromMinutes(5);

    options.LoginPath = "/Identity/Account/Login";
    options.AccessDeniedPath = "/Identity/Account/AccessDenied";
    options.SlidingExpiration = true;
});

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.UseMigrationsEndPoint();
}
else
{
    app.UseExceptionHandler("/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();

app.UseAuthentication();
app.UseAuthorization();

app.MapRazorPages();

app.Run();

The preceding code configures Identity with default option values. Services are made available to the app through dependency injection.

Identity is enabled by calling UseAuthentication. UseAuthentication adds authentication middleware to the request pipeline.

The template-generated app doesn't use authorization. app.UseAuthorization is included to ensure it's added in the correct order should the app add authorization. UseRouting, UseAuthentication, and UseAuthorization must be called in the order shown in the preceding code.

For more information on IdentityOptions, see IdentityOptions and Application Startup.

Scaffold Register, Login, LogOut, and RegisterConfirmation

Visual Studio

Add the Register, Login, LogOut, and RegisterConfirmation files. Follow the Scaffold identity into a Razor project with authorization instructions to generate the code shown in this section.

.NET CLI

If you created the project with name WebApp1, and you're not using SQLite, run the following commands. Otherwise, use the correct namespace for the ApplicationDbContext:

dotnet add package Microsoft.VisualStudio.Web.CodeGeneration.Design
dotnet aspnet-codegenerator identity -dc WebApp1.Data.ApplicationDbContext --files "Account.Register;Account.Login;Account.Logout;Account.RegisterConfirmation"

When using SQLite, append --useSqLite or -sqlite:

dotnet aspnet-codegenerator identity -dc WebApp1.Data.ApplicationDbContext --files "Account.Register;Account.Login;Account.Logout;Account.RegisterConfirmation" --useSqLite

PowerShell uses semicolon as a command separator. When using PowerShell, escape the semicolons in the file list or put the file list in double quotes, as the preceding example shows.

For more information on scaffolding Identity, see Scaffold identity into a Razor project with authorization.

Examine Register

When a user clicks the Register button on the Register page, the RegisterModel.OnPostAsync action is invoked. The user is created by CreateAsync(TUser) on the _userManager object:

public async Task<IActionResult> OnPostAsync(string returnUrl = null)
{
    returnUrl = returnUrl ?? Url.Content("~/");
    ExternalLogins = (await _signInManager.GetExternalAuthenticationSchemesAsync())
                                          .ToList();
    if (ModelState.IsValid)
    {
        var user = new IdentityUser { UserName = Input.Email, Email = Input.Email };
        var result = await _userManager.CreateAsync(user, Input.Password);
        if (result.Succeeded)
        {
            _logger.LogInformation("User created a new account with password.");

            var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
            code = WebEncoders.Base64UrlEncode(Encoding.UTF8.GetBytes(code));
            var callbackUrl = Url.Page(
                "/Account/ConfirmEmail",
                pageHandler: null,
                values: new { area = "Identity", userId = user.Id, code = code },
                protocol: Request.Scheme);

            await _emailSender.SendEmailAsync(Input.Email, "Confirm your email",
                $"Please confirm your account by <a href='{HtmlEncoder.Default.Encode(callbackUrl)}'>clicking here</a>.");

            if (_userManager.Options.SignIn.RequireConfirmedAccount)
            {
                return RedirectToPage("RegisterConfirmation", 
                                      new { email = Input.Email });
            }
            else
            {
                await _signInManager.SignInAsync(user, isPersistent: false);
                return LocalRedirect(returnUrl);
            }
        }
        foreach (var error in result.Errors)
        {
            ModelState.AddModelError(string.Empty, error.Description);
        }
    }

    // If we got this far, something failed, redisplay form
    return Page();
}

Disable default account verification

With the default templates, the user is redirected to the Account.RegisterConfirmation where they can select a link to have the account confirmed. The default Account.RegisterConfirmation is used only for testing, automatic account verification should be disabled in a production app.

To require a confirmed account and prevent immediate login at registration, set DisplayConfirmAccountLink = false in /Areas/Identity/Pages/Account/RegisterConfirmation.cshtml.cs:

[AllowAnonymous]
public class RegisterConfirmationModel : PageModel
{
    private readonly UserManager<IdentityUser> _userManager;
    private readonly IEmailSender _sender;

    public RegisterConfirmationModel(UserManager<IdentityUser> userManager, IEmailSender sender)
    {
        _userManager = userManager;
        _sender = sender;
    }

    public string Email { get; set; }

    public bool DisplayConfirmAccountLink { get; set; }

    public string EmailConfirmationUrl { get; set; }

    public async Task<IActionResult> OnGetAsync(string email, string returnUrl = null)
    {
        if (email == null)
        {
            return RedirectToPage("/Index");
        }

        var user = await _userManager.FindByEmailAsync(email);
        if (user == null)
        {
            return NotFound($"Unable to load user with email '{email}'.");
        }

        Email = email;
        // Once you add a real email sender, you should remove this code that lets you confirm the account
        DisplayConfirmAccountLink = false;
        if (DisplayConfirmAccountLink)
        {
            var userId = await _userManager.GetUserIdAsync(user);
            var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
            code = WebEncoders.Base64UrlEncode(Encoding.UTF8.GetBytes(code));
            EmailConfirmationUrl = Url.Page(
                "/Account/ConfirmEmail",
                pageHandler: null,
                values: new { area = "Identity", userId = userId, code = code, returnUrl = returnUrl },
                protocol: Request.Scheme);
        }

        return Page();
    }
}

Log in

The Login form is displayed when:

• The Log in link is selected.
• A user attempts to access a restricted page that they aren't authorized to access or when they haven't been authenticated by the system.

When the form on the Login page is submitted, the OnPostAsync action is called. PasswordSignInAsync is called on the _signInManager object.

public async Task<IActionResult> OnPostAsync(string returnUrl = null)
{
    returnUrl = returnUrl ?? Url.Content("~/");

    if (ModelState.IsValid)
    {
        // This doesn't count login failures towards account lockout
        // To enable password failures to trigger account lockout, 
        // set lockoutOnFailure: true
        var result = await _signInManager.PasswordSignInAsync(Input.Email,
                           Input.Password, Input.RememberMe, lockoutOnFailure: true);
        if (result.Succeeded)
        {
            _logger.LogInformation("User logged in.");
            return LocalRedirect(returnUrl);
        }
        if (result.RequiresTwoFactor)
        {
            return RedirectToPage("./LoginWith2fa", new
            {
                ReturnUrl = returnUrl,
                RememberMe = Input.RememberMe
            });
        }
        if (result.IsLockedOut)
        {
            _logger.LogWarning("User account locked out.");
            return RedirectToPage("./Lockout");
        }
        else
        {
            ModelState.AddModelError(string.Empty, "Invalid login attempt.");
            return Page();
        }
    }

    // If we got this far, something failed, redisplay form
    return Page();
}

For information on how to make authorization decisions, see Introduction to authorization in ASP.NET Core.

Log out

The Log out link invokes the LogoutModel.OnPost action.

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Logging;
using System.Threading.Tasks;

namespace WebApp1.Areas.Identity.Pages.Account
{
    [AllowAnonymous]
    public class LogoutModel : PageModel
    {
        private readonly SignInManager<IdentityUser> _signInManager;
        private readonly ILogger<LogoutModel> _logger;

        public LogoutModel(SignInManager<IdentityUser> signInManager, ILogger<LogoutModel> logger)
        {
            _signInManager = signInManager;
            _logger = logger;
        }

        public void OnGet()
        {
        }

        public async Task<IActionResult> OnPost(string returnUrl = null)
        {
            await _signInManager.SignOutAsync();
            _logger.LogInformation("User logged out.");
            if (returnUrl != null)
            {
                return LocalRedirect(returnUrl);
            }
            else
            {
                return RedirectToPage();
            }
        }
    }
}

In the preceding code, the code return RedirectToPage(); needs to be a redirect so that the browser performs a new request and the identity for the user gets updated.

SignOutAsync clears the user's claims stored in a cookie.

Post is specified in the Pages/Shared/_LoginPartial.cshtml:

@using Microsoft.AspNetCore.Identity
@inject SignInManager<IdentityUser> SignInManager
@inject UserManager<IdentityUser> UserManager

<ul class="navbar-nav">
@if (SignInManager.IsSignedIn(User))
{
    <li class="nav-item">
        <a  class="nav-link text-dark" asp-area="Identity" asp-page="/Account/Manage/Index" 
                                              title="Manage">Hello @User.Identity.Name!</a>
    </li>
    <li class="nav-item">
        <form class="form-inline" asp-area="Identity" asp-page="/Account/Logout" 
                                  asp-route-returnUrl="@Url.Page("/", new { area = "" })" 
                                  method="post" >
            <button  type="submit" class="nav-link btn btn-link text-dark">Logout</button>
        </form>
    </li>
}
else
{
    <li class="nav-item">
        <a class="nav-link text-dark" asp-area="Identity" asp-page="/Account/Register">Register</a>
    </li>
    <li class="nav-item">
        <a class="nav-link text-dark" asp-area="Identity" asp-page="/Account/Login">Login</a>
    </li>
}
</ul>

Test Identity

The default web project templates allow anonymous access to the home pages. To test Identity, add [Authorize]:

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Logging;

namespace WebApp1.Pages
{
    [Authorize]
    public class PrivacyModel : PageModel
    {
        private readonly ILogger<PrivacyModel> _logger;

        public PrivacyModel(ILogger<PrivacyModel> logger)
        {
            _logger = logger;
        }

        public void OnGet()
        {
        }
    }
}

If you are signed in, sign out. Run the app and select the Privacy link. You are redirected to the login page.

Explore Identity

To explore Identity in more detail:

• Create full identity UI source
• Examine the source of each page and step through the debugger.

Identity Components

All the Identity-dependent NuGet packages are included in the ASP.NET Core shared framework.

The primary package for Identity is Microsoft.AspNetCore.Identity. This package contains the core set of interfaces for ASP.NET Core Identity, and is included by Microsoft.AspNetCore.Identity.EntityFrameworkCore.

Migrating to ASP.NET Core Identity

For more information and guidance on migrating your existing Identity store, see Migrate Authentication and Identity.

Setting password strength

See Configuration for a sample that sets the minimum password requirements.

AddDefaultIdentity and AddIdentity

AddDefaultIdentity was introduced in ASP.NET Core 2.1. Calling AddDefaultIdentity is similar to calling the following:

• AddIdentity
• AddDefaultUI
• AddDefaultTokenProviders

See AddDefaultIdentity source for more information.

Prevent publish of static Identity assets

To prevent publishing static Identity assets (stylesheets and JavaScript files for Identity UI) to the web root, add the following ResolveStaticWebAssetsInputsDependsOn property and RemoveIdentityAssets target to the app's project file:

<PropertyGroup>
  <ResolveStaticWebAssetsInputsDependsOn>RemoveIdentityAssets</ResolveStaticWebAssetsInputsDependsOn>
</PropertyGroup>

<Target Name="RemoveIdentityAssets">
  <ItemGroup>
    <StaticWebAsset Remove="@(StaticWebAsset)" Condition="%(SourceId) == 'Microsoft.AspNetCore.Identity.UI'" />
  </ItemGroup>
</Target>

Next Steps

• ASP.NET Core Identity source code
• How to work with Roles in ASP.NET Core Identity

• See this GitHub issue for information on configuring Identity using SQLite.
• Configure Identity
• Create an ASP.NET Core app with user data protected by authorization
• Add, download, and delete user data to Identity in an ASP.NET Core project
• Enable QR code generation for TOTP authenticator apps in ASP.NET Core
• Migrate Authentication and Identity to ASP.NET Core
• Account confirmation and password recovery in ASP.NET Core
• Two-factor authentication with SMS in ASP.NET Core
• Host ASP.NET Core in a web farm