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.

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. For more detailed instructions about creating apps that use Identity, see the Next Steps section at the end of this article.

Microsoft identity platform is:

  • An evolution of the Azure Active Directory (Azure AD) developer platform.
  • Unrelated to ASP.NET Core Identity.

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:

IdentityServer4 is an OpenID Connect and OAuth 2.0 framework for ASP.NET Core 3.0. IdentityServer4 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

For more information, see Welcome to IdentityServer4.

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.

  • Select File > New > Project.
  • Select ASP.NET Core Web Application. Name the project WebApp1 to have the same namespace as the project download. Click OK.
  • Select an ASP.NET Core Web Application, then select Change Authentication.
  • Select Individual User Accounts and click OK.

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.

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

PM> Update-Database

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

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

Contextual menu on AspNetUsers table in SQL Server Object Explorer

Configure Identity services

Services are added in ConfigureServices. The typical pattern is to call all the Add{Service} methods, and then call all the services.Configure{Service} methods.

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlServer(
            Configuration.GetConnectionString("DefaultConnection")));
    services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
        .AddEntityFrameworkStores<ApplicationDbContext>();
    services.AddRazorPages();

    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;
    });

    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;
    });
}

The preceding highlighted 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.

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
        app.UseDatabaseErrorPage();
    }
    else
    {
        app.UseExceptionHandler("/Error");
        app.UseHsts();
    }

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

    app.UseRouting();

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

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapRazorPages();
    });
}

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, UseAuthorization, and UseEndpoints must be called in the order shown in the preceding code.

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

Scaffold Register, Login, and LogOut

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

Examine Register

When a user clicks the Register link, the RegisterModel.OnPostAsync action is invoked. The user is created by CreateAsync on the _userManager object. _userManager is provided by dependency injection):

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();
}

If the user was created successfully, the user is logged in by the call to _signInManager.SignInAsync.

See account confirmation for steps to prevent immediate login at registration.

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 (provided by dependency injection).

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();
}

The base Controller class exposes a User property that can be accessed from controller methods. For instance, you can enumerate User.Claims and make authorization decisions. For more information, 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:

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:

See AddDefaultIdentity source for more information.

Next Steps

By Rick Anderson

ASP.NET Core Identity is a membership system that adds login functionality to ASP.NET Core apps. 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.

Identity can be 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.

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

In this topic, you learn how to use Identity to register, log in, and log out a user. For more detailed instructions about creating apps that use Identity, see the Next Steps section at the end of this article.

AddDefaultIdentity and AddIdentity

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

See AddDefaultIdentity source for more information.

Create a Web app with authentication

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

  • Select File > New > Project.
  • Select ASP.NET Core Web Application. Name the project WebApp1 to have the same namespace as the project download. Click OK.
  • Select an ASP.NET Core Web Application, then select Change Authentication.
  • Select Individual User Accounts and click OK.

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.

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

PM> Update-Database

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

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

Contextual menu on AspNetUsers table in SQL Server Object Explorer

Configure Identity services

Services are added in ConfigureServices. The typical pattern is to call all the Add{Service} methods, and then call all the services.Configure{Service} methods.

public void ConfigureServices(IServiceCollection services)
{
    services.Configure<CookiePolicyOptions>(options =>
    {
        options.CheckConsentNeeded = context => true;
        options.MinimumSameSitePolicy = SameSiteMode.None;
    });

    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlServer(
            Configuration.GetConnectionString("DefaultConnection")));
    services.AddDefaultIdentity<IdentityUser>()
        .AddDefaultUI(UIFramework.Bootstrap4)
        .AddEntityFrameworkStores<ApplicationDbContext>();

    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;
    });

    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;
    });

    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
}

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.

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
        app.UseDatabaseErrorPage();
    }
    else
    {
        app.UseExceptionHandler("/Error");
        app.UseHsts();
    }

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

    app.UseAuthentication();

    app.UseMvc();
}

For more information, see the IdentityOptions Class and Application Startup.

Scaffold Register, Login, and LogOut

Follow the Scaffold identity into a Razor project with authorization instructions to generate the code shown in this section.

Add the Register, Login, and LogOut files.

Examine Register

When a user clicks the Register link, the RegisterModel.OnPostAsync action is invoked. The user is created by CreateAsync on the _userManager object. _userManager is provided by dependency injection):

public async Task<IActionResult> OnPostAsync(string returnUrl = null)
{
    returnUrl = returnUrl ?? Url.Content("~/");
    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);
            var callbackUrl = Url.Page(
                "/Account/ConfirmEmail",
                pageHandler: null,
                values: new { 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>.");

            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();
}

If the user was created successfully, the user is logged in by the call to _signInManager.SignInAsync.

Note: See account confirmation for steps to prevent immediate login at registration.

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 (provided by dependency injection).

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();
}

The base Controller class exposes a User property that you can access from controller methods. For instance, you can enumerate User.Claims and make authorization decisions. For more information, 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
            {
                // This needs to be a redirect so that the browser performs a new
                // request and the identity for the user gets updated.
                return RedirectToPage();
            }
        }
    }
}

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] to the Privacy page.

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

namespace WebApp1.Pages
{
    [Authorize]
    public class PrivacyModel : PageModel
    {
        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:

Identity Components

All the Identity dependent NuGet packages are included in the Microsoft.AspNetCore.App metapackage.

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.

Next Steps