PM> Install-Package SAML2Core

services.AddAuthentication(sharedOptions =>
{
    sharedOptions.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
    sharedOptions.DefaultSignInScheme = CookieAuthenticationDefaults.AuthenticationScheme;
})
   .AddSamlCore(options =>
            {

            // SignOutPath- The endpoint for the idp to perform its signout action. default is "/signedout"
                //options.SignOutPath = "/signmeout";

            // EntityId (REQUIRED) - The Relying Party Identifier e.g. https://my.la.gov.local
                options.ServiceProvider.EntityId = Configuration["AppConfiguration:ServiceProvider:EntityId"];

            // There are two ways to provide FederationMetadata:
                // Option 1 - A FederationMetadata.xml already exists for your application
                // options.MetadataAddress = @"FederationMetadata.xml";

                // Option 2 - Have the middleware generate the FederationMetadata.xml file for you
                options.MetadataAddress = Configuration["AppConfiguration:IdentityProvider:MetadataAddress"];

                options.RequireMessageSigned = false;
                options.WantAssertionsSigned = true;

            // Have the middleware create the metadata file for you
                // The default is false. If you don't want a file generated by the middleware, comment the line below.
                options.CreateMetadataFile = true;

                // If you want to specify the filename and path for the generated metadata file do so below:
                //options.DefaultMetadataFileName = "MyMetadataFilename.xml";
                //options.DefaultMetadataFolderLocation = "MyPath";

                // (REQUIRED IF) signing AuthnRequest with Sp certificate to Idp. The value here is the certifcate serial number.
                //if the certificate is in the project. make sure the path to ti is correct. 
                //password value is needed to access private keys for signature and decryption.
                options.ServiceProvider.X509Certificate2 = new X509Certificate2(@"democert.pfx", "1234");

                //if you want to search in cert store - can be used for production
                options.ServiceProvider.X509Certificate2 = new Cryptography.X509Certificates.Extension.X509Certificate2(
                    Configuration["AppConfiguration:ServiceProvider:CertificateSerialNumber"],
                    StoreName.My,
                    StoreLocation.LocalMachine,
                    X509FindType.FindBySerialNumber);

                // Force Authentication (optional) - Is authentication required?
                options.ForceAuthn = true;


                options.WantAssertionsSigned = false;
                options.RequireMessageSigned = true;

           // Service Provider Properties (optional) - These set the appropriate tags in the metadata.xml file
                options.ServiceProvider.ServiceName = "My Test Site";
                options.ServiceProvider.Language = "en-US";
                options.ServiceProvider.OrganizationDisplayName = "Louisiana State Government";
                options.ServiceProvider.OrganizationName = "Louisiana State Government";
                options.ServiceProvider.OrganizationURL = "https://my.test.site.gov";
                options.ServiceProvider.ContactPerson = new ContactType()
                {
                    Company = "Louisiana State Government - OTS",
                    GivenName = "Dina Heidar",
                    EmailAddress = new[] { "dina.heidar@la.gov" },
                    contactType = ContactTypeType.technical,
                    TelephoneNumber = new[] { "+1 234 5678" }
                };
                //Events - Modify events below if you want to log errors, add custom claims, etc.
                options.Events.OnRemoteFailure = context =>
                {
                    return Task.FromResult(0);
                };
                options.Events.OnTicketReceived = context =>
                {  //if you need to add custom claims here
                    
                    //example:
                    //var identity = context.Principal.Identity as ClaimsIdentity;
                    //var claims = context.Principal.Claims;                 
                    //if (claims.Any(c => c.Type == "userID"))
                    //{
                    //    var userId = claims.FirstOrDefault(c => c.Type == "userID").Value;
                    //    var name = claims.FirstOrDefault(c => c.Type == ClaimTypes.Name);
                    //    identity.TryRemoveClaim(name);
                    //    identity.AddClaim(new Claim(ClaimTypes.Name, userId));
                    //}
                    return Task.FromResult(0);
                };
            })

.AddCookie();

app.UseAuthentication();