Very simple SAML 2.0 consumer module for ASP.NET/C#
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Latest commit 55971cd Jun 17, 2018
Failed to load latest commit information. Update Jun 17, 2018
Saml.cs Fixed signature reference check. Minor refactoring Jun 7, 2017


Very simple SAML 2.0 "consumer" implementation in C#. It's a SAML client library, not a SAML server, allows adding SAML single-sign-on to your ASP.NET app, but not to provide auth services to other apps.

Consists of one short C# file you can throw into your project (or install via nuget) and start using it. Originally forked from OneLogin's .NET SAML library, but we had to fix a lot of stuff...


How SAML works?

SAML workflow has 2 steps:

  1. User is redirected to the SAML provider (where he authenticates)
  2. User is redirected back to your app, where you validate the payload

Here's how you do it:

1. Redirecting the user to the saml provider:

//specify the SAML provider url here, aka "Endpoint"
var samlEndpoint = "";

var request = new AuthRequest(
	"", //put your app's "unique ID" here
	"" //assertion Consumer Url - the redirect URL where the provider will send authenticated users
//generate the provider URL
string url = request.GetRedirectUrl(samlEndpoint);

//then redirect your user to the above "url" var
//for example, like this:

2. User has been redirected back

User is sent back to your app - you need to validate the SAML response ("assertion") that you recieved via POST.

Here's an example of how you do it in ASP.NET MVC

//ASP.NET MVC action method... But you can easily modify the code for Web-forms etc.
public ActionResult SamlConsume()
	//specify the certificate that your SAML provider has given to you
	string samlCertificate = @"-----BEGIN CERTIFICATE-----

	Saml.Response samlResponse = new Response(samlCertificate);
	samlResponse.LoadXmlFromBase64(Request.Form["SAMLResponse"]); //SAML providers usually POST the data into this var

	if (samlResponse.IsValid())
		//WOOHOO!!! user is logged in
		//Some more optional stuff for you
		//lets extract username/firstname etc
		string username, email, firstname, lastname;
			username = samlResponse.GetNameID();
			email = samlResponse.GetEmail();
			firstname = samlResponse.GetFirstName();
			lastname = samlResponse.GetLastName();
		catch(Exception ex)
			//insert error handling code
			//no, really, please do
			return null;
		//user has been authenticated, put your code here, like set a cookie or something...
		//or call FormsAuthentication.SetAuthCookie() or something

(NEW!) Nuget

I've published this to Nuget.

Install-Package AspNetSaml

This will simply add the cs-file to the root of your project.

A version of this library has been used for years in production in our helpdesk app.