System.Security.Cryptography.RSACryptoServiceProvider.Decrypt C# (CSharp) Method

        public byte[] Decrypt(byte[] rgb, bool fOAEP)
        {
            if (rgb == null)
            {
                throw new ArgumentNullException(nameof(rgb));
            }

            // Save the KeySize value to a local because it has non-trivial cost.
            int keySize = KeySize;

            // size check -- must be at most the modulus size
            if (rgb.Length > (keySize / 8))
            {
                throw new CryptographicException(SR.Format(SR.Cryptography_Padding_DecDataTooBig, Convert.ToString(keySize / 8)));
            }

            byte[] decryptedKey;
            CapiHelper.DecryptKey(SafeKeyHandle, rgb, rgb.Length, fOAEP, out decryptedKey);
            return decryptedKey;
        }

        public RecordType AddRecord(string OName, string OPoint)
        {
            byte[] Name = Convert.FromBase64String(OName);
            byte[] Point = Convert.FromBase64String(OPoint);
            StreamReader sr = new StreamReader(Server.MapPath("App_Data\rightcolor_private.xml"));
            string ALL = sr.ReadToEnd();
            sr.Close();

            RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(2048);
            RSA.FromXmlString(ALL);

            string RealName = System.Text.Encoding.UTF8.GetString(RSA.Decrypt(Name, false));
            long RealPoint = long.Parse(System.Text.Encoding.UTF8.GetString(RSA.Decrypt(Point, false)));

            RecordType AllowInsert = RecordType.None;
            long ForeverMax = (from inc in Data.Records orderby inc.Point descending select inc.Point).Skip(9).Take(1).SingleOrDefault();
            if (RealPoint > ForeverMax)
            {
                AllowInsert = RecordType.Forever;
                goto Insert;
            }
            long MonthMax = (from inc in Data.Records where inc.AddDate > DateTime.Now.AddMonths(-1) orderby inc.Point descending select inc.Point).Skip(9).Take(1).SingleOrDefault();
            if (RealPoint > MonthMax)
            {
                AllowInsert = RecordType.Month;
                goto Insert;
            }
            long WeekMax = (from inc in Data.Records where inc.AddDate > DateTime.Now.AddDays(-7) orderby inc.Point descending select inc.Point).Skip(9).Take(1).SingleOrDefault();
            if (RealPoint > WeekMax)
            {
                AllowInsert = RecordType.Week;
                goto Insert;
            }
            long DayMax = (from inc in Data.Records where inc.AddDate > DateTime.Now.AddDays(-1) orderby inc.Point descending select inc.Point).Skip(9).Take(1).SingleOrDefault();
            if (RealPoint > DayMax)
            {
                AllowInsert = RecordType.Day;
            }
            Insert:
            if (AllowInsert != RecordType.None)
            {
                Record NewRecord = new Record();
                NewRecord.Person = RealName;
                NewRecord.Point = RealPoint;
                NewRecord.AddDate = DateTime.Now;
                Data.Records.InsertOnSubmit(NewRecord);
                Data.SubmitChanges();
            }
            return AllowInsert;
        }