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title	author	description	monikerRange	ms.author	ms.date	uid
Use cookie authentication without ASP.NET Core Identity	rick-anderson	Learn how to use cookie authentication without ASP.NET Core Identity.	>= aspnetcore-3.1	riande	1/1/2022	security/authentication/cookie

By Rick Anderson

:::moniker range=">= aspnetcore-6.0"

ASP.NET Core Identity is a complete, full-featured authentication provider for creating and maintaining logins. However, a cookie-based authentication provider without ASP.NET Core Identity can be used. For more information, see xref:security/authentication/identity.

View or download sample code (how to download)

For demonstration purposes in the sample app, the user account for the hypothetical user, Maria Rodriguez, is hardcoded into the app. Use the Email address maria.rodriguez@contoso.com and any password to sign in the user. The user is authenticated in the AuthenticateUser method in the Pages/Account/Login.cshtml.cs file. In a real-world example, the user would be authenticated against a datastore.

Add the Authentication Middleware services with the xref:Microsoft.Extensions.DependencyInjection.AuthenticationServiceCollectionExtensions.AddAuthentication%2A and xref:Microsoft.Extensions.DependencyInjection.CookieExtensions.AddCookie%2A methods.
Call xref:Microsoft.AspNetCore.Builder.AuthAppBuilderExtensions.UseAuthentication%2A and xref:Microsoft.AspNetCore.Builder.AuthorizationAppBuilderExtensions.UseAuthorization%2A to set the HttpContext.User property and run the Authorization Middleware for requests. UseAuthentication and UseAuthorization must be called before Map methods such as xref:Microsoft.AspNetCore.Builder.RazorPagesEndpointRouteBuilderExtensions.MapRazorPages%2A and xref:Microsoft.AspNetCore.Builder.ControllerEndpointRouteBuilderExtensions.MapDefaultControllerRoute%2A

[!code-csharp]

xref:Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationDefaults.AuthenticationScheme passed to AddAuthentication sets the default authentication scheme for the app. AuthenticationScheme is useful when there are multiple instances of cookie authentication and the app needs to authorize with a specific scheme. Setting the AuthenticationScheme to CookieAuthenticationDefaults.AuthenticationScheme provides a value of "Cookies" for the scheme. Any string value can be used that distinguishes the scheme.

The app's authentication scheme is different from the app's cookie authentication scheme. When a cookie authentication scheme isn't provided to xref:Microsoft.Extensions.DependencyInjection.CookieExtensions.AddCookie*, it uses CookieAuthenticationDefaults.AuthenticationScheme. The CookieAuthenticationDefaults.AuthenticationScheme GitHub Source shows it's set to "Cookies".

The authentication cookie's xref:Microsoft.AspNetCore.Http.CookieBuilder.IsEssential property is set to true by default. Authentication cookies are allowed when a site visitor hasn't consented to data collection. For more information, see xref:security/gdpr#essential-cookies.

The xref:Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationOptions class is used to configure the authentication provider options.

Configure xref:Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationOptions in the xref:Microsoft.Extensions.DependencyInjection.CookieExtensions.AddCookie%2A method:

[!code-csharp]

The Cookie Policy Middleware (GitHub Source) xref:Microsoft.AspNetCore.Builder.CookiePolicyAppBuilderExtensions.UseCookiePolicy%2A enables cookie policy capabilities. Middleware is processed in the order it's added:

app.UseCookiePolicy(cookiePolicyOptions);

Use xref:Microsoft.AspNetCore.Builder.CookiePolicyOptions provided to the Cookie Policy Middleware to control global characteristics of cookie processing and hook into cookie processing handlers when cookies are appended or deleted.

The default xref:Microsoft.AspNetCore.Builder.CookiePolicyOptions.MinimumSameSitePolicy value is SameSiteMode.Lax to permit OAuth2 authentication. To strictly enforce a same-site policy of SameSiteMode.Strict, set the MinimumSameSitePolicy. Although this setting breaks OAuth2 and other cross-origin authentication schemes, it elevates the level of cookie security for other types of apps that don't rely on cross-origin request processing.

var cookiePolicyOptions = new CookiePolicyOptions
{
    MinimumSameSitePolicy = SameSiteMode.Strict,
};

The Cookie Policy Middleware setting for MinimumSameSitePolicy can affect the setting of Cookie.SameSite in CookieAuthenticationOptions settings according to the matrix below.

MinimumSameSitePolicy	Cookie.SameSite	Resultant Cookie.SameSite setting
SameSiteMode.None	SameSiteMode.None SameSiteMode.Lax SameSiteMode.Strict	SameSiteMode.None SameSiteMode.Lax SameSiteMode.Strict
SameSiteMode.Lax	SameSiteMode.None SameSiteMode.Lax SameSiteMode.Strict	SameSiteMode.Lax SameSiteMode.Lax SameSiteMode.Strict
SameSiteMode.Strict	SameSiteMode.None SameSiteMode.Lax SameSiteMode.Strict	SameSiteMode.Strict SameSiteMode.Strict SameSiteMode.Strict

To create a cookie holding user information, construct a xref:System.Security.Claims.ClaimsPrincipal. The user information is serialized and stored in the cookie.

Create a xref:System.Security.Claims.ClaimsIdentity with any required xref:System.Security.Claims.Claims and call xref:Microsoft.AspNetCore.Authentication.AuthenticationHttpContextExtensions.SignInAsync* to sign in the user. Login.cshtml.cs in the sample app contains the following code:

[!code-csharp]

[!INCLUDErequest localized comments]

SignInAsync creates an encrypted cookie and adds it to the current response. If AuthenticationScheme isn't specified, the default scheme is used.

xref:Microsoft.AspNetCore.Authentication.AuthenticationProperties.RedirectUri is only used on a few specific paths by default, for example, the login path and logout paths. For more information see the CookieAuthenticationHandler source.

ASP.NET Core's Data Protection system is used for encryption. For an app hosted on multiple machines, load balancing across apps, or using a web farm, configure data protection to use the same key ring and app identifier.

Sign out

To sign out the current user and delete their cookie, call xref:Microsoft.AspNetCore.Authentication.AuthenticationHttpContextExtensions.SignOutAsync*:

[!code-csharp]

If CookieAuthenticationDefaults.AuthenticationScheme or "Cookies" isn't used as the scheme, supply the scheme used when configuring the authentication provider. Otherwise, the default scheme is used. For example, if "ContosoCookie" is used as the scheme, supply the scheme used when configuring the authentication provider.

When the browser closes it automatically deletes session based cookies (non-persistent cookies), but no cookies are cleared when an individual tab is closed. The server is not notified of tab or browser close events.

React to back-end changes

Once a cookie is created, the cookie is the single source of identity. If a user account is disabled in back-end systems:

The app's cookie authentication system continues to process requests based on the authentication cookie.
The user remains signed into the app as long as the authentication cookie is valid.

The xref:Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationEvents.ValidatePrincipal* event can be used to intercept and override validation of the cookie identity. Validating the cookie on every request mitigates the risk of revoked users accessing the app.

One approach to cookie validation is based on keeping track of when the user database changes. If the database hasn't been changed since the user's cookie was issued, there's no need to re-authenticate the user if their cookie is still valid. In the sample app, the database is implemented in IUserRepository and stores a LastChanged value. When a user is updated in the database, the LastChanged value is set to the current time.

In order to invalidate a cookie when the database changes based on the LastChanged value, create the cookie with a LastChanged claim containing the current LastChanged value from the database:

var claims = new List<Claim>
{
    new Claim(ClaimTypes.Name, user.Email),
    new Claim("LastChanged", {Database Value})
};

var claimsIdentity = new ClaimsIdentity(
    claims,
    CookieAuthenticationDefaults.AuthenticationScheme);

await HttpContext.SignInAsync(
    CookieAuthenticationDefaults.AuthenticationScheme, 
    new ClaimsPrincipal(claimsIdentity));

To implement an override for the ValidatePrincipal event, write a method with the following signature in a class that derives from xref:Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationEvents:

ValidatePrincipal(CookieValidatePrincipalContext)

The following is an example implementation of CookieAuthenticationEvents:

[!code-csharp]

Register the events instance during cookie service registration. Provide a scoped service registration for your CustomCookieAuthenticationEvents class:

[!code-csharp]

Consider a situation in which the user's name is updated—a decision that doesn't affect security in any way. If you want to non-destructively update the user principal, call context.ReplacePrincipal and set the context.ShouldRenew property to true.

[!WARNING] The approach described here is triggered on every request. Validating authentication cookies for all users on every request can result in a large performance penalty for the app.

Persistent cookies

You may want the cookie to persist across browser sessions. This persistence should only be enabled with explicit user consent with a "Remember Me" checkbox on sign in or a similar mechanism.

The following code snippet creates an identity and corresponding cookie that survives through browser closures. Any sliding expiration settings previously configured are honored. If the cookie expires while the browser is closed, the browser clears the cookie once it's restarted.

Set xref:Microsoft.AspNetCore.Authentication.AuthenticationProperties.IsPersistent to true in xref:Microsoft.AspNetCore.Authentication.AuthenticationProperties:

// using Microsoft.AspNetCore.Authentication;

await HttpContext.SignInAsync(
    CookieAuthenticationDefaults.AuthenticationScheme,
    new ClaimsPrincipal(claimsIdentity),
    new AuthenticationProperties
    {
        IsPersistent = true
    });

An absolute expiration time can be set with xref:Microsoft.AspNetCore.Authentication.AuthenticationProperties.ExpiresUtc. To create a persistent cookie, IsPersistent must also be set. Otherwise, the cookie is created with a session-based lifetime and could expire either before or after the authentication ticket that it holds. When ExpiresUtc is set, it overrides the value of the xref:Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationOptions.ExpireTimeSpan option of xref:Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationOptions, if set.

The following code snippet creates an identity and corresponding cookie that lasts for 20 minutes. This ignores any sliding expiration settings previously configured.

// using Microsoft.AspNetCore.Authentication;

await HttpContext.SignInAsync(
    CookieAuthenticationDefaults.AuthenticationScheme,
    new ClaimsPrincipal(claimsIdentity),
    new AuthenticationProperties
    {
        IsPersistent = true,
        ExpiresUtc = DateTime.UtcNow.AddMinutes(20)
    });

:::moniker-end :::moniker range="< aspnetcore-6.0"

View or download sample code (how to download)

Configuration

In the Startup.ConfigureServices method, create the Authentication Middleware services with the xref:Microsoft.Extensions.DependencyInjection.AuthenticationServiceCollectionExtensions.AddAuthentication%2A and xref:Microsoft.Extensions.DependencyInjection.CookieExtensions.AddCookie%2A methods:

[!code-csharp]

xref:Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationDefaults.AuthenticationScheme passed to AddAuthentication sets the default authentication scheme for the app. AuthenticationScheme is useful when there are multiple instances of cookie authentication and you want to authorize with a specific scheme. Setting the AuthenticationScheme to CookieAuthenticationDefaults.AuthenticationScheme provides a value of "Cookies" for the scheme. You can supply any string value that distinguishes the scheme.

In Startup.Configure, call UseAuthentication and UseAuthorization to set the HttpContext.User property and run Authorization Middleware for requests. Call the UseAuthentication and UseAuthorization methods before calling UseEndpoints:

[!code-csharp]

The xref:Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationOptions class is used to configure the authentication provider options.

Set CookieAuthenticationOptions in the service configuration for authentication in the Startup.ConfigureServices method:

services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
    .AddCookie(options =>
    {
        ...
    });

Cookie Policy Middleware enables cookie policy capabilities. Adding the middleware to the app processing pipeline is order sensitive—it only affects downstream components registered in the pipeline.

app.UseCookiePolicy(cookiePolicyOptions);

var cookiePolicyOptions = new CookiePolicyOptions
{
    MinimumSameSitePolicy = SameSiteMode.Strict,
};

The Cookie Policy Middleware setting for MinimumSameSitePolicy can affect the setting of Cookie.SameSite in CookieAuthenticationOptions settings according to the matrix below.

MinimumSameSitePolicy	Cookie.SameSite	Resultant Cookie.SameSite setting
SameSiteMode.None	SameSiteMode.None SameSiteMode.Lax SameSiteMode.Strict	SameSiteMode.None SameSiteMode.Lax SameSiteMode.Strict
SameSiteMode.Lax	SameSiteMode.None SameSiteMode.Lax SameSiteMode.Strict	SameSiteMode.Lax SameSiteMode.Lax SameSiteMode.Strict
SameSiteMode.Strict	SameSiteMode.None SameSiteMode.Lax SameSiteMode.Strict	SameSiteMode.Strict SameSiteMode.Strict SameSiteMode.Strict

To create a cookie holding user information, construct a xref:System.Security.Claims.ClaimsPrincipal. The user information is serialized and stored in the cookie.

[!code-csharp]

[!INCLUDErequest localized comments]

SignInAsync creates an encrypted cookie and adds it to the current response. If AuthenticationScheme isn't specified, the default scheme is used.

Sign out

To sign out the current user and delete their cookie, call xref:Microsoft.AspNetCore.Authentication.AuthenticationHttpContextExtensions.SignOutAsync*:

[!code-csharp]

If CookieAuthenticationDefaults.AuthenticationScheme (or "Cookies") isn't used as the scheme (for example, "ContosoCookie"), supply the scheme used when configuring the authentication provider. Otherwise, the default scheme is used.

React to back-end changes

Once a cookie is created, the cookie is the single source of identity. If a user account is disabled in back-end systems:

The app's cookie authentication system continues to process requests based on the authentication cookie.
The user remains signed into the app as long as the authentication cookie is valid.

In order to invalidate a cookie when the database changes based on the LastChanged value, create the cookie with a LastChanged claim containing the current LastChanged value from the database:

var claims = new List<Claim>
{
    new Claim(ClaimTypes.Name, user.Email),
    new Claim("LastChanged", {Database Value})
};

var claimsIdentity = new ClaimsIdentity(
    claims, 
    CookieAuthenticationDefaults.AuthenticationScheme);

await HttpContext.SignInAsync(
    CookieAuthenticationDefaults.AuthenticationScheme, 
    new ClaimsPrincipal(claimsIdentity));

ValidatePrincipal(CookieValidatePrincipalContext)

The following is an example implementation of CookieAuthenticationEvents:

using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authentication.Cookies;

public class CustomCookieAuthenticationEvents : CookieAuthenticationEvents
{
    private readonly IUserRepository _userRepository;

    public CustomCookieAuthenticationEvents(IUserRepository userRepository)
    {
        // Get the database from registered DI services.
        _userRepository = userRepository;
    }

    public override async Task ValidatePrincipal(CookieValidatePrincipalContext context)
    {
        var userPrincipal = context.Principal;

        // Look for the LastChanged claim.
        var lastChanged = (from c in userPrincipal.Claims
                           where c.Type == "LastChanged"
                           select c.Value).FirstOrDefault();

        if (string.IsNullOrEmpty(lastChanged) ||
            !_userRepository.ValidateLastChanged(lastChanged))
        {
            context.RejectPrincipal();

            await context.HttpContext.SignOutAsync(
                CookieAuthenticationDefaults.AuthenticationScheme);
        }
    }
}

Register the events instance during cookie service registration in the Startup.ConfigureServices method. Provide a scoped service registration for your CustomCookieAuthenticationEvents class:

services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
    .AddCookie(options =>
    {
        options.EventsType = typeof(CustomCookieAuthenticationEvents);
    });

services.AddScoped<CustomCookieAuthenticationEvents>();

[!WARNING] The approach described here is triggered on every request. Validating authentication cookies for all users on every request can result in a large performance penalty for the app.

Persistent cookies

You may want the cookie to persist across browser sessions. This persistence should only be enabled with explicit user consent with a "Remember Me" checkbox on sign in or a similar mechanism.

Set xref:Microsoft.AspNetCore.Authentication.AuthenticationProperties.IsPersistent to true in xref:Microsoft.AspNetCore.Authentication.AuthenticationProperties:

// using Microsoft.AspNetCore.Authentication;

await HttpContext.SignInAsync(
    CookieAuthenticationDefaults.AuthenticationScheme,
    new ClaimsPrincipal(claimsIdentity),
    new AuthenticationProperties
    {
        IsPersistent = true
    });

The following code snippet creates an identity and corresponding cookie that lasts for 20 minutes. This ignores any sliding expiration settings previously configured.

// using Microsoft.AspNetCore.Authentication;

await HttpContext.SignInAsync(
    CookieAuthenticationDefaults.AuthenticationScheme,
    new ClaimsPrincipal(claimsIdentity),
    new AuthenticationProperties
    {
        IsPersistent = true,
        ExpiresUtc = DateTime.UtcNow.AddMinutes(20)
    });

:::moniker-end

27 KiB Raw Permalink Blame History

Use cookie authentication without ASP.NET Core Identity

Add cookie authentication

Cookie Policy Middleware

Create an authentication cookie

Sign out

React to back-end changes

Persistent cookies

Absolute cookie expiration

Configuration

Cookie Policy Middleware

Create an authentication cookie

Sign out

React to back-end changes

Persistent cookies

Absolute cookie expiration

27 KiB

Raw Permalink Blame History