gistfile1.cs

using System;
using System.Collections.Generic;
using System.Security.Cryptography;
using System.Text;
using Norm;
using System.Linq;

namespace MongoSandbox
{
    class Program
    {
        static void Main(string[] args)
        {
            const string connectionString = 
                "mongodb://projecteuleruser:Pa$$w0rd@localhost/ProjectEuler";

            using (var database = Mongo.Create(connectionString))
            {
                var users = database.GetCollection<User>();

                users.Find().ForEach(users.Delete);

                users.Save(new User
                                {
                                    Username = "ldebroglie",
                                    Email = "louis.debroglie@paris-sorbonne.fr",
                                    Name = "Louis De Broglie",
                                    Password = "wavemechanics".Hash("ldebroglie")
                                });

                users.Save(new User
                                {
                                    Username = "wheisenberg",
                                    Email = "werner.heisenberg@uni-muenchen.de",
                                    Name = "Werner Heisenberg",
                                    Password = "matrixmechanics".Hash("wheisenberg")
                                });

                users.Find().ForEach(Console.WriteLine); 

                Console.WriteLine("Authenticated: {0}", 
                                  (users.AsQueryable().
                                         Any(u => u.Username == "wheisenberg" && 
                                                  u.Password == "wavemechanics".Hash("wheisenberg"))));
            }

            Console.ReadKey();
        }
    }

    public class User
    {
        public User() { Id = Guid.NewGuid(); }

        public Guid Id { get; set; }
        public string Username { get; set; }
        public string Password { get; set; }
        public string Name { get; set; }
        public string Email { get; set; }

        public override string ToString()
        {
            return string.Format("Username: {0}, Password: {1}, Name: {2}, Email: {3}",
                Username,
                Password,
                Name,
                Email);
        }
    }

    public static class StringExtensions
    {
        public static string Hash(this string value, string salt)
        {
            return SHA1.Create().
                    ComputeHash(Encoding.UTF8.GetBytes(salt + value)).
                    Select(x => x.ToString("x2")).
                    Aggregate((a, x) => a + x); 
        }
    }

    public static class IEnumerableExtensions
    {
        public static void ForEach<T>(this IEnumerable<T> items, Action<T> action)
        {
            foreach (var item in items) action(item);
        }
    }
}