AspNetCore.Docs/aspnetcore/security/authorization/limitingidentitybyscheme.md

title	author	description	keywords	ms.author	manager	ms.date	ms.topic	ms.assetid	ms.technology	ms.prod	uid
Limiting identity by scheme - ASP.NET Core	rick-anderson	This article explains how to limit identity to a specific schema when working with multiple authentication methods.	ASP.NET Core,identity,authentication scheme	riande	wpickett	10/10/2017	article	d3d6ca1b-b4b5-4bf7-898e-dcd90ec1bf8c	aspnet	asp.net-core	security/authorization/limitingidentitybyscheme

Limiting identity by scheme

In some scenarios, such as Single Page Applications, it's common to use multiple authentication methods. For example, your application may use cookie-based authentication to log in and JWT bearer authentication for JavaScript requests. In some cases, you may have multiple instances of an authentication middleware. For example, two cookie middlewares where one contains a basic identity and one is created when a multi-factor authentication has triggered (because the user requested an operation that requires extra security).

ASP.NET Core 2.x

An authentication scheme is named when the authentication service is configured during authentication. For example:

public void ConfigureServices(IServiceCollection services)
{
    // Code omitted for brevity

    services.AddAuthentication()
        .AddCookie(options => {
            options.LoginPath = "/Account/Unauthorized/";
            options.AccessDeniedPath = "/Account/Forbidden/";
        })
        .AddJwtBearer(options => {
            options.Audience = "http://localhost:5001/";
            options.Authority = "http://localhost:5000/";
        });

In the preceding code, two authentication services have been added: one for cookies and one for bearer.

[!NOTE] When adding multiple authentication middlewares, ensure that no middleware is configured to run automatically. You do this by invoking AddAuthentication with no arguments. If you fail to do this, filtering by scheme doesn't work. For example, AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme) makes cookies run automatically.

ASP.NET Core 1.x

Authentication schemes are named when authentication middlewares are configured during authentication. For example:

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    // Code omitted for brevity

    app.UseCookieAuthentication(new CookieAuthenticationOptions()
    {
        AuthenticationScheme = "Cookie",
        LoginPath = "/Account/Unauthorized/",
        AccessDeniedPath = "/Account/Forbidden/",
        AutomaticAuthenticate = false
    });
    
    app.UseJwtBearerAuthentication(new JwtBearerOptions()
    {
        AuthenticationScheme = "Bearer",
        AutomaticAuthenticate = false,
        Audience = "http://localhost:5001/",
        Authority = "http://localhost:5000/"
    });

In the preceding code, two authentication middlewares have been added: one for cookies and one for bearer.

[!NOTE] When adding multiple authentication middlewares, ensure that no middleware is configured to run automatically. You do this by setting the AuthenticationOptions.AutomaticAuthenticate property to false. If you fail to do this, filtering by scheme doesn't work.

---

Selecting the scheme with the Authorize attribute

At the point of authorization, you indicate the middleware to be used. The simplest way to select the middleware with which you wish to authorize is to pass a comma-delimited list of authentication schemes to the [Authorize] attribute. The [Authorize] attribute specifies the authentication scheme or schemes to use regardless of whether a default is configured. For example:

ASP.NET Core 2.x

[Authorize(AuthenticationSchemes = "Cookie,Bearer")]
public class MixedController : Controller

ASP.NET Core 1.x

[Authorize(ActiveAuthenticationSchemes = "Cookie,Bearer")]
public class MixedController : Controller

---

In the example above, both the cookie and bearer middlewares run and have a chance to create and append an identity for the current user. By specifying a single scheme only, the specified middleware runs.

ASP.NET Core 2.x

[Authorize(AuthenticationSchemes = "Bearer")]
public class MixedController : Controller

ASP.NET Core 1.x

[Authorize(ActiveAuthenticationSchemes = "Bearer")]
public class MixedController : Controller

---

In this case, only the middleware with the "Bearer" scheme runs. Any cookie-based identities are ignored.

Selecting the scheme with policies

If you prefer to specify the desired schemes in policy, you can set the AuthenticationSchemes collection when adding your policy:

services.AddAuthorization(options =>
{
    options.AddPolicy("Over18", policy =>
    {
        policy.AuthenticationSchemes.Add("Bearer");
        policy.RequireAuthenticatedUser();
        policy.Requirements.Add(new Over18Requirement());
    });
});

In this example, the "Over18" policy only runs against the identity created by the "Bearer" middleware.