description: Use Identity with an ASP.NET Core app. Learn how to set password requirements (RequireDigit, RequiredLength, RequiredUniqueChars, and more).
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](xref:security/authentication/social/index).
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](https://github.com/aspnet/Docs/tree/master/aspnetcore/security/authentication/identity/sample/src/ASPNETCore-IdentityDemoComplete/) ([how to download)](xref:index#how-to-download-a-sample)).
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](/dotnet/api/microsoft.extensions.dependencyinjection.identityservicecollectionuiextensions.adddefaultidentity?view=aspnetcore-2.1#Microsoft_Extensions_DependencyInjection_IdentityServiceCollectionUIExtensions_AddDefaultIdentity__1_Microsoft_Extensions_DependencyInjection_IServiceCollection_System_Action_Microsoft_AspNetCore_Identity_IdentityOptions__) was introduced in ASP.Core 2.1. Calling `AddDefaultIdentity` is similar to calling the following:
See [AddDefaultIdentity source](https://github.com/aspnet/Identity/blob/2634637fd535b229762b5e4a49cdd128f4d8f12e/src/UI/IdentityServiceCollectionUIExtensions.cs#L47-L64) for more information.
The generated project provides [ASP.NET Core Identity](xref:security/authentication/identity) as a [Razor Class Library](xref:razor-pages/ui-class).
### 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.
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. The following code doesn't include the template generated `CookiePolicyOptions`:
The preceding code configures Identity with default option values. Services are made available to the app through [dependency injection](xref:fundamentals/dependency-injection).
Identity is enabled by calling [UseAuthentication](/dotnet/api/microsoft.aspnetcore.builder.authappbuilderextensions.useauthentication#Microsoft_AspNetCore_Builder_AuthAppBuilderExtensions_UseAuthentication_Microsoft_AspNetCore_Builder_IApplicationBuilder_). `UseAuthentication` adds authentication [middleware](xref:fundamentals/middleware/index) to the request pipeline.
Identity is enabled for the application by calling `UseAuthentication` in the `Configure` method. `UseAuthentication` adds authentication [middleware](xref:fundamentals/middleware/index) to the request pipeline.
These services are made available to the application through [dependency injection](xref:fundamentals/dependency-injection).
Identity is enabled for the application by calling `UseIdentity` in the `Configure` method. `UseIdentity` adds cookie-based authentication [middleware](xref:fundamentals/middleware/index) to the request pipeline.
For more information, see the [IdentityOptions Class](/dotnet/api/microsoft.aspnetcore.identity.identityoptions) and [Application Startup](xref:fundamentals/startup).
Follow the [Scaffold identity into a Razor project with authorization](xref:security/authentication/scaffold-identity#scaffold-identity-into-a-razor-project-with-authorization) instructions.
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.
When a user clicks the **Register** link, the `RegisterModel.OnPostAsync` action is invoked. The user is created by [CreateAsync](/dotnet/api/microsoft.aspnetcore.identity.usermanager-1.createasync#Microsoft_AspNetCore_Identity_UserManager_1_CreateAsync__0_System_String_) on the `_userManager` object. `_userManager` is provided by dependency injection):
When a user clicks the **Register** link, the `Register` action is invoked on `AccountController`. The `Register` action creates the user by calling `CreateAsync` on the `_userManager` object (provided to `AccountController` by dependency injection):
**Note:** See [account confirmation](xref:security/authentication/accconfirm#prevent-login-at-registration) for steps to prevent immediate login at registration.
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).
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 [Authorization](xref:security/authorization/index).
The Login form is displayed when users select the **Log in** link or are redirected when accessing a page that requires authentication. When the user submits the form on the Login page, the `AccountController``Login` action is called.
[SignOutAsync](/dotnet/api/microsoft.aspnetcore.identity.signinmanager-1.signoutasync#Microsoft_AspNetCore_Identity_SignInManager_1_SignOutAsync) clears the user's claims stored in a cookie. Don't redirect after calling `SignOutAsync` or the user will **not** be signed out.
The default web project templates allow anonymous access to the home pages. To test Identity, add [`[Authorize]`](/dotnet/api/microsoft.aspnetcore.authorization.authorizeattribute) to the About page.
The primary package for Identity is [Microsoft.AspNetCore.Identity](https://www.nuget.org/packages/Microsoft.AspNetCore.Identity/). This package contains the core set of interfaces for ASP.NET Core Identity, and is included by `Microsoft.AspNetCore.Identity.EntityFrameworkCore`.
