atakanozbancom/Models/classes/SecretProtector.cs

using System;
using System.Text;
using System.Web.Security;

namespace atakanozbancom.Models.classes
{
    public static class SecretProtector
    {
        private static readonly string[] Purposes = { "atakanozbancom.TotpSecret.v1" };

        public static string Protect(string plaintext)
        {
            if (string.IsNullOrEmpty(plaintext))
                return plaintext;

            var bytes = Encoding.UTF8.GetBytes(plaintext);
            var protectedBytes = MachineKey.Protect(bytes, Purposes);
            return Convert.ToBase64String(protectedBytes);
        }

        public static string Unprotect(string protectedValue)
        {
            if (string.IsNullOrEmpty(protectedValue))
                return protectedValue;

            try
            {
                var protectedBytes = Convert.FromBase64String(protectedValue);
                var bytes = MachineKey.Unprotect(protectedBytes, Purposes);
                return bytes == null ? null : Encoding.UTF8.GetString(bytes);
            }
            catch
            {
                return null;
            }
        }

        public static bool LooksProtected(string value)
        {
            if (string.IsNullOrWhiteSpace(value))
                return false;

            try
            {
                var bytes = Convert.FromBase64String(value);
                return bytes.Length > 16;
            }
            catch
            {
                return false;
            }
        }
    }
}