Developers.Italia.SPID.SAML.AuthRequestOptions options = new Developers.Italia.SPID.SAML.AuthRequestOptions()
 {
    //Request Unique Identifier
    UUID = Guid.NewGuid().ToString(),
    //Service Provider Unique Identifier (url like https://www.dotnetcode.it can be ok)
    SPUID = "MyServiceProviderUniqueIdentifier",
    //SPID Authentication Level (1/2/3)
    SPIDLevel = Developers.Italia.SPID.SAML.SPIDLevel.SPIDL1,
    //Identity Provider Url For SAML Request
    Destination = "https://www.myserviceprovider.com/samlurl",
    //Service Provider Consumer Service Index - Normally Callback URL (refer to Service Provider Metadata)
    AssertionConsumerServiceIndex = 0,
    //Service Provider Consuming Service Index - Normally Requested User Data(refer to Service Provider Metadata)
    AttributeConsumingServiceIndex = 0
 };

 Developers.Italia.SPID.SAML.AuthRequest request = new Developers.Italia.SPID.SAML.AuthRequest(options);

 string rsaXmlKey = "<![CDATA[<RSAKeyValue><Modulus>rBPwxOB3QM+Rhz+/...</RSAKeyValue>";
 
 X509Certificate2 signinCert = new X509Certificate2("MyCertPath.pfx", "MyCertPassword", X509KeyStorageFlags.Exportable);

 string samlRequest = request.GetSignedAuthRequest(signinCert, rsaXmlKey);

public IActionResult SPID()
{
    Developers.Italia.SPID.SAML.AuthRequestOptions options = new Developers.Italia.SPID.SAML.AuthRequestOptions()
    {
        //Request Unique Identifier
        UUID = Guid.NewGuid().ToString(),
        //Service Provider Unique Identifier (url like https://www.dotnetcode.it can be ok)
        SPUID = "https://www.dotnetcode.it",
        //SPID Authentication Level (1/2/3)
        SPIDLevel = Developers.Italia.SPID.SAML.SPIDLevel.SPIDL1,
        //Identity Provider Url For SAML Request
        Destination = "https://spidposte.test.poste.it/jod-fs/ssoservicepost",
        //Service Provider Consumer Service Index - Normally Callback URL (refer to Service Provider Metadata)
        AssertionConsumerServiceIndex = 0,
        //Service Provider Consuming Service Index - Normally Requested User Data(refer to Service Provider Metadata)
        AttributeConsumingServiceIndex = 0
    };

    Developers.Italia.SPID.SAML.AuthRequest request = new Developers.Italia.SPID.SAML.AuthRequest(options);


    string rsaXmlKey = "<![CDATA[<RSAKeyValue><Modulus>rBPwxOB3QM+Rhz+/...</RSAKeyValue>";
    X509Certificate2 signinCert = new X509Certificate2("MyCertPath.pfx", "MyCertPassword", X509KeyStorageFlags.Exportable);

    string samlRequest = request.GetSignedAuthRequest(signinCert, rsaXmlKey);


            
    string returnUrl = "/";

    if (!string.IsNullOrEmpty(HttpContext.Request.Query["redirectUrl"]))
    {
        returnUrl = HttpContext.Request.Query["redirectUrl"];
    }

    ViewData["FormUrlAction"] = options.Destination;
    ViewData["SAMLRequest"] = System.Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(samlRequest));
    ViewData["RelayState"] = System.Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(returnUrl));

    return View();
}

// POST: SpidSaml/ACS
[HttpPost]
public ActionResult ACS(IFormCollection collection)
{
    string samlResponse = "";
    string redirect = "";
    SAML.AuthResponse resp = new SAML.AuthResponse();
    try
    {
        samlResponse = Encoding.UTF8.GetString(Convert.FromBase64String(collection["SAMLResponse"]));
        redirect = Encoding.UTF8.GetString(Convert.FromBase64String(collection["RelayState"]));
                
        resp.Deserialize(samlResponse);
                
    }
    catch (Exception ex)
    {
        //TODO LOG
    }

    ViewData["SAMLResponse"] = resp;
    ViewData["RelayState"] = redirect;
    return View();
}
}