Step-by-Step Guide to Implementing IdP-Initiated SAML SSO in .NET Core

Ibrahim Jaber
4 min readMar 2, 2023

As businesses continue to adopt cloud-based software solutions, managing multiple user accounts and passwords can become an overwhelming task. One way to simplify this process is by implementing Single Sign-On (SSO) authentication. In this blog post, we will walk through how to implement IdP-initiated SSO using the Security Assertion Markup Language (SAML) protocol in a .NET Core application using C#.

To make things easier, we will be using a third-party NuGet package called Kentor.AuthServices to implement the SAML authentication. Kentor.AuthServices is an open-source library that provides an easy-to-use interface for adding SAML authentication to your .NET Core application.

Before we dive into the implementation details, let’s first define what IdP-initiated SSO is and why it’s useful. IdP-initiated SSO allows users to log in to multiple applications without having to enter their credentials each time. This is achieved by having a trusted identity provider (IdP) authenticate the user and provide a token that can be used to access other applications. This not only saves time for the user but also enhances security by reducing the number of credentials that need to be managed.

To make this more relatable, let’s consider a fun business problem. Imagine that you run a travel company that offers a variety of travel services, including flights, hotels, and car rentals. Your customers often use multiple services, and you want to make it easier for them to access these services without having to log in multiple times. By implementing SSO, your customers can log in once and then seamlessly access all of the services that they need.

Now that we understand the benefits of SSO, let’s dive into the implementation details.

Step 1: Install the Kentor.AuthServices NuGet package

To get started, create a new .NET Core project in Visual Studio or your preferred development environment. Then, install the Kentor.AuthServices NuGet package by running the following command in the Package Manager Console:

Install-Package Kentor.AuthServices.AspNetCore

This will install the required dependencies for SAML authentication in your project.

Step 2: Configure SAML authentication in your application

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Ibrahim Jaber

Software developer | Programming and Blockchain enthusiast | If you'd like to buy me coffee: https://ko-fi.com/ibrahimjaber