C# - Windows CD Key auslesen

namespace CD_Key
{
    public class Win32
    {
        #region Properties
        /// <summary>
        /// Reads the Windows CD key from the registry and returns it as string separated by '-' chars.
        /// </summary>
        public static string WindowsCDKey
        {
            get
            {
                RegistryKey rKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows NT\CurrentVersion");
                byte[] rpk = (byte[])rKey.GetValue("DigitalProductId", new byte[0]);

                string strKey = "";

                const int iRPKOffset = 52;
                const string strPossibleChars = "BCDFGHJKMPQRTVWXY2346789";
                int i = 28;

                do
                {
                    long lAccu = 0;
                    int j = 14;

                    do
                    {
                        lAccu *= 256; lAccu += Convert.ToInt64(rpk[iRPKOffset + j]);

                        rpk[iRPKOffset + j] =
                            Convert.ToByte(
                            Convert.ToInt64(Math.Floor((float)lAccu / 24.0f)) & Convert.ToInt64(255)
                            );

                        lAccu %= 24;

                        j -= 1;
                    }
                    while (j >= 0);

                    i -= 1;
                    strKey = strPossibleChars[(int)lAccu].ToString() + strKey;

                    if ((0 == ((29 - i) % 6)) && (-1 != i))
                    {
                        i -= 1;

                        strKey = "-" + strKey;
                    }
                }
                while (i >= 0);

                return strKey;
            }
        }
        
        /// <summary>
        /// Reads the Windows CD key from the registry and returns it as string array.
        /// </summary>
        public static string[] WindowsCDKeyParts
        {
            get
            {
                string[] strKeyParts = WindowsCDKey.Split('-');
                return strKeyParts;
            }
        }
        #endregion
    }
}