Bad Data Exception while Decrypting in C# .Net

Hi,
I am trying to Encrypt /Decrypt the string using RSA Algoritham i found in some site.

if i Run the same code in Windows Application, it works good. (I can save the Encrypted string in SQL Server, and fetch and Decrypt it back to original string). 

But, I am facing the "Bad data" exception in Web Application.

kindly Help...

Below is the source code:   

//**** Code for Encrypting Decrypting using RSA Algorithm *****
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;
namespace RSA_EncryptionDecryption
{
    public class RSA_EncryptDecrypt
    {
        static public byte[] RSAEncryption(byte[] Data, RSAParameters RSAKey, bool DoOAEPPadding)
        {
            try
            {
                byte[] encryptedData;
                using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
                {
                    RSA.ImportParameters(RSAKey);
                    encryptedData = RSA.Encrypt(Data, DoOAEPPadding);
                }
                return encryptedData;
            }
            catch (CryptographicException e)
            {
                Console.WriteLine(e.Message);
                return null;
            }
        }



        static public byte[] RSADecryption(byte[] Data, RSAParameters RSAKey, bool DoOAEPPadding)
        {
            try
            {
                byte[] decryptedData;
                using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
                {
                    RSA.ImportParameters(RSAKey);
                    decryptedData = RSA.Decrypt(Data, DoOAEPPadding);
                }
                return decryptedData;
            }
            catch (CryptographicException e)
            {
                Console.WriteLine(e.ToString());
                return null;
            }
        }
    }
}

//This is code to  pass String as parameter to Encrypt/Decrypt function..

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Drawing;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;
using RSA_EncryptionDecryption;
using System.Data.SqlClient;
public partial class _Default : System.Web.UI.Page
{
    UnicodeEncoding ByteConverter = new UnicodeEncoding();
    RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
    byte[] plaintext;
    byte[] encryptedtext;
    byte[] encryptedtext_fromDB;

    string Connstr = "Data Source=MyPC;Initial Catalog=MyDB;Integrated Security=True";

    protected void Page_Load(object sender, EventArgs e)
    {
        if (Page.IsPostBack == false)
        {
            lblError.Text = "";
            TxtForEncryption.Text = "";
            LblDecryptedText.Text = "";
        }
    }

    protected void TxtForEncryption_TextChanged(object sender, EventArgs e) {  }

    #region Encrypt
    protected void CmdEncrypt_Click(object sender, EventArgs e)
    {
                  plaintext = ByteConverter.GetBytes(TxtForEncryption.Text);
            encryptedtext = RSA_EncryptDecrypt.RSAEncryption(plaintext, RSA.ExportParameters(false), false);
            LblEncrptedText.Text = ByteConverter.GetString(encryptedtext);
            using (SqlConnection cn = new SqlConnection(Connstr))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    cmd.CommandText = "SAVEPASSWORD";
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.AddWithValue("@UPassword", encryptedtext);
                    cmd.Connection = cn;
                    cn.Open();
                    cmd.ExecuteNonQuery();
                }
          }
    }
    #endregion

    #region Decrypt
    protected void CmdDecrypt_Click(object sender, EventArgs e) 
    {
            using (SqlConnection cn = new SqlConnection(Connstr))
            {
                string Q = "select UPassword from USER_PASS where Userid in(select Max(userid) from USER_PASS)";
                using (SqlCommand cmd = new SqlCommand(Q, cn))
                {
                    using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                    {
                        using (DataTable dt = new DataTable())
                        {
                            cn.Open();
                            da.Fill(dt);

                            cn.Close();
                            int x = dt.Rows.Count;
                            foreach (DataRow dr in dt.Rows)
                            {
                                encryptedtext_fromDB = (byte[])dr["UPassword"];
                            }
                        }
                    }
                }
            }

            byte[] decryptedtex = RSA_EncryptDecrypt.RSADecryption(encryptedtext_fromDB, RSA.ExportParameters(true), false);
            LblDecryptedText.Text = ByteConverter.GetString(decryptedtex);
    }
    #endregion
}