Program.cs

using System;
using Npam;

namespace ConsoleApplication
{
    public class Program
    {
	//const string PamServiceName = "password-auth"; //For RHEL based Linux
        const string PamServiceName = "passwd";

        public static void Main(string[] args)
        {
            Console.Write("Username: ");
	        string user = Console.ReadLine();
            Console.Write("Password: ");
	        string password  = AcceptInputNoEcho();

            if (NpamUser.Authenticate(PamServiceName, user, password)) 
            {
                Console.WriteLine("AUTHENTICATION - SUCCESS!");
                Console.WriteLine("\rUSER GROUPS:");
                foreach (var userGroup in NpamUser.GetGroups(user))
                {
                    Console.WriteLine("\t{0}", userGroup);
                }
                Console.WriteLine("\rUSER INFO:");
                Console.WriteLine("\t{0}", NpamUser.GetAccountInfo(user));
                
            } 
            else 
            {
                Console.WriteLine("AUTHENTICATION - FAILURE!");
            }
        }
        
        private static string AcceptInputNoEcho()
        {
            string password = "";
            while (true)
            {
                ConsoleKeyInfo i = Console.ReadKey(true);
                if (i.Key == ConsoleKey.Enter)
                {
                    Console.WriteLine();
                    break;
                }
                else if (i.Key == ConsoleKey.Backspace)
                {
                    if (password.Length > 0)
                    {
                        password = password.Substring(0, password.Length - 1);
                    }
                }
                else
                {
                    password += (i.KeyChar);
                }
            }   
            return password;
        }

    }
}