.NET is a developer platform made up of tools, programming languages, and libraries for building many different types of applications. The base platform provides components that apply to all different types of apps. Additional frameworks, such as ASP.NET, extend .NET with components for building specific types of apps.

ASP.NET is an open source web framework, created by Microsoft, for building modern web apps and services with .NET. ASP.NET is cross platform and runs on Windows, Linux, macOS, and Docker. The server-side web application framework ASP.NET, also known as Active Server Pages Network Enabled Technologies, is free to use. It is intended for use in web development to create interactive websites, programs, and services. Let’s take a closer look at ASP.Net Authentication.

What Is ASP.NET Authentication?

Microsoft’s ASP.NET is an open source framework for creating contemporary web sites, services, and applications. It is supported by Linux, macOS, Windows, and Docker. IAuthenticationService is the foundation of the ASP.NET authentication framework. The service can authenticate users in ASP.NET applications thanks to registered authentication handlers.

ASP.NET Authentication Concepts

Authentication Schemes

A scheme for authentication identifies the authentication handler in charge of generating the appropriate set of claims. The names of authentication handlers and the particular configuration settings for each handler’s instance are known as authentication schemes. Schemes can be used to discuss authentication and challenge or forbid associated handler behavior.

Authentication Handler

The actions of an authentication scheme are carried out by authentication handlers. From AuthenticationHandler <TOptions> or IAuthenticationHandler, handlers can be derived. Authenticating users is its main objective. The associated authentication scheme’s configuration and the context of incoming requests will influence how the authentication handler responds.

The handler creates an AuthenticationTicket object, which represents a user’s identity, if the authentication is successful. A “failure” or “no result” is returned if the authentication fails. The handler offers ways to thwart or oppose actions taken by a user. Unauthorized users will be denied access, while unauthenticated users will be presented with a challenge.

Authentication Challenge

When unauthenticated users try to access a resource that needs authentication, the authorization system takes an additional precaution known as authentication challenges. For instance, if an anonymous user clicks on a login link or requests access to a restricted resource, the IAuthenticationService may issue a challenge. The challenge is issued by the authorization system using a default authentication scheme (or a specified scheme if one exists).

Forbid Action

If authenticated users attempt to access resources without the required permissions, the authorization system triggers the ‘forbid’ action for authentication schemes. Users are informed by forbidden actions when they have been authenticated but are denied access to a resource. The following situations, for instance, may result in the system forbidding authentication:

• An access-restricted page is redirected to by a cookie authentication scheme.
• A 403 (forbidden) error is returned by a JWT bearer scheme.
• A page where users can request access to a protected resource is the destination of an authentication scheme.

ASP.NET Core Identity

An API that supports UI login features is called Core Identity. You can manage a variety of user data elements with it, such as user profiles, passwords, roles, tokens, and claims. Users can create accounts using the login information from ASP.NET Core Identity. A supported external login provider, such as Google, Facebook, Twitter, or Microsoft accounts, can also be used to create accounts.

The SQL Server database that houses usernames, profile information, and passwords is typically used to configure Identity. A different persistent store, like Azure Table Storage, is also an option.

Providers of authentication for each tenant

There is no integrated method for multi-tenant authentication in ASP.NET Core. We advise customers to think about Orchard Core or ABP Framework for multi-tenant authentication even though they are able to create one using the built-in features.

Orchard Core is an ASP.NET Core-based multi-tenant, open-source, and modular app framework and an app framework with a content management system (CMS) added on top. ABP Framework supports various architectural patterns including modularity, microservices, domain driven design, and multi-tenancy. See ABP Framework source on GitHub.

ASP.NET Multi-Factor Authentication

During a sign-in event, multi-factor authentication (MFA) asks the user for multiple forms of identification. Passwords are frequently used as the first identification factor, and a fingerprint scan, a FIDO2 key, or a verification code sent to the user’s phone can be used as the second factor. Adding MFA as a requirement for an application greatly increases the security of authentication.

Using ASP.NET Core Identity offers native support for 2FA (2-factor authentication). Set the IdentityUserTKey> to enable or disable 2FA for a specific user. Property TwoFactorEnabled. When utilizing ASP.NET Core Identity, cMFA with the Time-based One-Time Password (TOTP) algorithm is additionally natively supported. This approach is compatible with authenticator programs like the Google Authenticator and the Microsoft Authenticator.

Users accessing sensitive pages in an ASP.NET Core Identity application can be forced to use MFA. This is beneficial for programs with various levels of access for various identities. Users can log in using their password, for instance, to view profile information, but administrators need MFA to access admin pages.

Wrapping Up

Finding a user’s identity is the first step in user authentication. We take this action to make sure they are who they claim to be. Once we are confident in our ability to trust them, we can log them into our app and give them access to resources that are intended for logged-in users only. Now that you know how to authenticate and log in a user to an ASP.NET application, hopefully you are off to a good start.