Quick Overview:
Security is always in the top priority and objective whenever a company starts developing an application with any technology.

The same is the scenario with ASP.NET Core development. Some of the primary goals of data security are ensuring data integrity and allowing only valid users to utilize the assets. Further, the most effective technique is to perform authentication to accomplish this objective.

ASP.NET Core offers various in-built approaches to implementing authentication, leading to preventing unauthorized clients.

By reading further, you can clear all your doubts and understand the top classifications of ASP.NET Core authentication. Moreover, you will know the significant elements functioning to validate every account.

What does Authentication mean in ASP.NET Core, and Why is it essential?

Authentication in dotnet core is a security operation that aims to verify a person’s identity, computer system, or mobile device. It works in collaboration with authorization, which aims to confirm whether a user has relevant permission to access specific files or not.

It ensures that only legitimate people access the resources, and others get denied. The .NET authentication and authorization function is closely under the Identity Management approach, whose primary aim is to validate the user through these mechanisms.

If we simplify it more, Authentication asks whether the user is the right person or not, and asp.net core authorization asks whether the user has permission to access the file. Identity Management is the main component that asks these questions to each user.

There are various authentication methods available under Identity management. However, local authentication is the most common among them. The identity verification process requires a username and password. ASP.NET includes a built-in module for this purpose, which does not rely on any external elements for configuration.

Besides this, it has the disadvantage of storing user credentials in a centralized database, which disables utilizing the same authentication for multiple services. But you don’t have to worry; you can fix it by implementing a decentralized authentication system, which seamlessly works for different applications and services.

The local authentication system has two extended versions

  • Windows Authentication
  • Form Authentication.

The .NET developers prefer these two for configuring the de-centralized authentication.

In implementing Centralized Identity Management, engineers must follow and comply with the asp.net core app with defined standards. As a result, the system becomes capable of verifying the end-user and providing only relevant access to resources. The procedure is also known as the Single Sign-On or the SSO.

Besides this, Microsoft also offers Passport Authentication and reliably working centralized authentication to tighten the app security. The most common authentication example is logging into your Gmail, Yahoo, or Outlook account.

The application asks for your username and password whenever you try to access your mail account. If the credentials are correct, then only you get logged in. Moreover, the mailing system will deal with you as a valid user and provide all the necessary controls.

When you are developing an ASP.NET application, authentication plays an important role.

The first line of defense is to permit only recognized users to prevent cyber-attacks and malicious activities across business apps. It aids in maintaining the app performance and user data security and builds customer relationships.

Primary Authentication Mechanisms used for ASP.NET Core Apps

  • Windows Authentication
  • Form Authentication
  • Passport Authentication

Windows Authentication

It is an operating system-based authentication mechanism linked with ASP.NET Core applications for verifying the user identity.

Primarily, large enterprises prefer it for maintaining the security of their intra-network, inclusive of a Microsoft Windows Active Directory Server. Under this .NET core authentication mechanism, all the hosts available in the network have to authenticate themselves before utilizing the ASP.NET application.

For seamlessly configuring Windows Authentication functionality, you must host your app only on the following servers:

  • IIS (Internet Information Service)
  • Kestrel
  • sys

ASP.NET Core can disallow Windows authentication by default if you use any other server. In addition, to avail of the best-in-class benefits of this functionality, all the apps and systems must be in the same domain.

Form Authentication

Authenticating users through login forms is the most basic, standard, and widespread security strategy.

Nowadays, every website, web app, and mobile app provides a form for inputting usernames and passwords before accessing the resources. The same is the case with ASP.NET Core apps.

It allows the creation of a login and sign-up page for registering new users and verifying the current end-users.

When you sign up using the form, it stores your username and password details in a database. After performing hashing and salting, the system stores all the information. It helps to maintain data integrity and confidentiality.

Further, when the user tries to sing-in, the application checks the credentials with the parameters available in the database. If both the strings match each other, access gets granted; otherwise, it is denied.

For implementing the form authentication in ASP.NET Core software, you have to change the mode to form and set authorization as provided below:

<authentication mode="Forms">
<forms loginUrl="login.aspx" />
<deny users="?" />

Passport Authentication

Passport Authentication is an advanced system that allows users to log into different web apps and services without inputting credentials at each platform.

To strengthen this approach, Microsoft extends its functionality by adding its secure sign-in function. It provides the same security assurance as the Secure Socket Layer to protect confidential data.

When passport authentication is enabled, all the user details get stored in an encrypted cookie, which authenticates the user on different websites. In case the cookie doesn’t work, the user gets redirected to the passport server. After completing the login formalities, the person automatically navigates to the website.

The Fundamental Components of ASP.NET Core Authentication

  • Authentication Handlers
  • Authentication Scheme

Authentication Handlers

In ASP.NET Core applications, the Authentication handler is the primary component that manages the core operations for validating the user’s identity. It leads to configuring the behavior of the Authentication scheme.

It works based on end-user login requests and the policies implemented by the developer to assure user legitimacy.

Whenever a person tries to log in, Handler creates a ticket for it and uses it throughout the process. If the request is well-founded, ASP.NET authentication is successful. Otherwise, the user returns to the login page, or no result string is displayed.

In addition, it has built-in mechanisms for forbidding and challenging the resource access instruction from the user. It assures to offer access to only authenticated users.

If the person cannot log in, the app forbids its access or executes the asp.net core challenge module for re-authenticating themselves.

To configure the Authentication Handler, you must add the following code structure to the startup.cs file:

public void ConfigureServices(IServiceCollection services)

Once you add the above-illustrated code, your application will start using the Cookie and JWT Authentication handler system.

In addition, you can extend the functionalities of these two handler options by using the following code.

For Cookie Authentication Handler:

.AddCookie("Cookies", options =>
options.LoginPath = "/Account/Login";
options.LogoutPath = "/Account/Logout";
options.AccessDeniedPath = "/Account/AccessDenied";
options.ReturnUrlParameter = "ReturnUrl";

For JWT Bearer Authentication Handler:

services.AddAuthentication(x =>
.AddJwtBearer(x =>
x.RequireHttpsMetadata = true;
x.SaveToken = true;
x.TokenValidationParameters = new TokenValidationParameters
ValidateIssuer = true,
ValidIssuer = jwtTokenConfig.Issuer,
ValidateAudience = true,
ValidAudience = jwtTokenConfig.Audience,
ValidateIssuerSigningKey = true,
RequireExpirationTime = false,
ValidateLifetime = true,
ClockSkew = TimeSpan.Zero,
IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(jwtTokenConfig.Secret))

After defining all the crucial parameters, you can ensure that your app prevents unauthenticated users from accessing and utilizing resources.

Authentication Scheme

It is known as the Authentication Scheme when you define an Authentication Handler option under the AddAuthentication() method.

For example, When you configure the Authentication Handler in the startup file and add JWT Bearer and Cookie modules inside it.


As a result, AddJwtBearer() and .AddCookie() are Authentication schemes.

In ASP.NET Core development, every scheme has a unique name and consists of a handler. Moreover, it leverages engineers to define every scheme parameter according to business requirements.

Moreover, every handler has its name by default, but you can modify it for comfort and readability purposes. Whether it’s Cookie or JWT Bearer, it simultaneously provides its default settings in the classes CookieAuthenticationDeafults and JwtBearerDeafults.

After accessing these classes, you can change the values and implement code per your project goal.

Further, for defining the custom scheme name, you can follow the below-provided syntax:

.AddCookie("Cookies 2");

The above code will set the name of schemes to Bearer, Cookies, and Cookies2. You must be wondering, if only two Authentication handler options are available, then how are there three in this code? Let’s clarify it.

ASP.NET Core allows its users to add multiple Authentication schemes. The only term is to set different names for each Authentication scheme, which helps the app quickly differentiate and execute them.

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Concluding Up

Allowing only registered and valid users to access the app resources is a crucial objective of ASP.NET Core development. And for achieving it, authentication is a necessary mechanism that every developer must enable.

Most the company and security experts prefer Windows, Passport, and Form Authentication, as it aids developers and end-users. Each approach saves the client’s time and maintains security according to defined standards.

In addition, ASP.NET Core authentication is managed through two major components: Authentication Handler and Authentication Scheme.

Only a few ASP.NET developers are well-versed in theoretical and practical knowledge of authentication, and those are not easy to find. However, Positiwise Software makes your search easy by providing a world-class team of .NET Core developers experienced in creating secure, high-performing, and reliable applications.

Parag Mehta

Verified Expert in Software & Web App Engineering

Parag Mehta, the CEO and Founder of Positiwise Software Pvt Ltd has extensive knowledge of the development niche. He is implementing custom strategies to craft highly-appealing and robust applications for its clients and supporting employees to grow and ace the tasks. He is a consistent learner and always provides the best-in-quality solutions, accelerating productivity.

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