namespace WindowsFormsApplication2
{
    public partial class loginpage : Form
    {
        public loginpage()
        {
            InitializeComponent();
        }

        // Connection String
        string cs = @"Data Source=MS-LAPTOPSQLEXPRESS;Initial Catalog=break;Integrated Security=True;User Instance=False;Context Connection=False;MultiSubnetFailover=False;TransparentNetworkIPResolution=False";
        //btn_Submit Click event

        public sealed class SecurePasswordHasher
        {
            /// <summary>
            /// Size of salt
            /// </summary>
            private const int SaltSize = 16;

            /// <summary>
            /// Size of hash
            /// </summary>
            private const int HashSize = 20;

            /// <summary>
            /// Creates a hash from a password
            /// </summary>
            /// <param name="password">the password</param>
            /// <param name="iterations">number of iterations</param>
            /// <returns>the hash</returns>
            public static string Hash(string password, int iterations)
            {
                //create salt
                byte[] salt;
                new RNGCryptoServiceProvider().GetBytes(salt = new byte[SaltSize]);

                //create hash
                var pbkdf2 = new Rfc2898DeriveBytes(password, salt, iterations);
                var hash = pbkdf2.GetBytes(HashSize);

                //combine salt and hash
                var hashBytes = new byte[SaltSize + HashSize];
                Array.Copy(salt, 0, hashBytes, 0, SaltSize);
                Array.Copy(hash, 0, hashBytes, SaltSize, HashSize);

                //convert to base64
                var base64Hash = Convert.ToBase64String(hashBytes);

                //format hash with extra information
                return string.Format("$MYHASH$V1${0}${1}", iterations, base64Hash);
            }

            /// <summary>
            /// Creates a hash from a password with 10000 iterations
            /// </summary>
            /// <param name="password">the password</param>
            /// <returns>the hash</returns>
            public static string Hash(string password)
            {
                return Hash(password, 10000);
            }

            /// <summary>
            /// Check if hash is supported
            /// </summary>
            /// <param name="hashString">the hash</param>
            /// <returns>is supported?</returns>
            public static bool IsHashSupported(string hashString)
            {
                return hashString.Contains("$MYHASH$V1$");
            }

            /// <summary>
            /// verify a password against a hash
            /// </summary>
            /// <param name="password">the password</param>
            /// <param name="hashedPassword">the hash</param>
            /// <returns>could be verified?</returns>
            public static bool Verify(string password, string hashedPassword)
            {
                //check hash
                if (!IsHashSupported(hashedPassword))
                {
                    throw new NotSupportedException("The hashtype is not supported");
                }

                //extract iteration and Base64 string
                var splittedHashString = hashedPassword.Replace("$MYHASH$V1$", "").Split('$');
                var iterations = int.Parse(splittedHashString[0]);
                var base64Hash = splittedHashString[1];

                //get hashbytes
                var hashBytes = Convert.FromBase64String(base64Hash);

                //get salt
                var salt = new byte[SaltSize];
                Array.Copy(hashBytes, 0, salt, 0, SaltSize);

                //create hash with given salt
                var pbkdf2 = new Rfc2898DeriveBytes(password, salt, iterations);
                byte[] hash = pbkdf2.GetBytes(HashSize);

                //get result
                for (var i = 0; i < HashSize; i++)
                {
                    if (hashBytes[i + SaltSize] != hash[i])
                    {
                        return false;
                    }
                }
                return true;
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            //Hash
            var hash = SecurePasswordHasher.Hash("password");

            //Verify
            var result = SecurePasswordHasher.Verify("password", hash);

            if (txtUsername.Text == "" || txt_Password.Text == "")
            {
                MessageBox.Show("Please provide a Username and Password");
                return;
            }

            try
            {
                //Create SqlConnection
                SqlConnection con = new SqlConnection(cs);

                SqlCommand cmd = new SqlCommand("Select * from tabl_login where UserName = @username and Password = @password", con);
                cmd.Parameters.AddWithValue("@username", txtUsername.Text);
                cmd.Parameters.AddWithValue("@password", txt_Password.Text);

                con.Open();

                SqlDataAdapter adapt = new SqlDataAdapter(cmd);
                DataSet ds = new DataSet();
                adapt.Fill(ds);

                con.Close();

                int count = ds.Tables[0].Rows.Count;

                //If count is equal to 1, than show frmMain form
                if (count == 1)
                {
                    MessageBox.Show("Login Successful!");

                    Form1 objFrmMain = new Form1();
                    this.Hide();
                    objFrmMain.ShowDialog();
                    this.Close();
                }
                else
                {
                    MessageBox.Show("Login Failed!");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void button1_Click_1(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}