hi i am using asp.net web application. when user registerd his password saved as encrypted to sql server databse from my asp.net form.  but when i want  to show users password in gridview as decrypt password it is showing error like below when exicute

Server Error in '/' Application.

The input data is not a complete block.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.  Exception Details: System.Security.Cryptography.CryptographicException: The input data is not a complete block. Source Error: 

Line 75:                     {
Line 76:                         cs.Write(cipherBytes, 0, cipherBytes.Length);
Line 77:                         cs.Close();
Line 78:                     }
Line 79:                     cipherText = Encoding.Unicode.GetString(ms.ToArray());

Source File: F:\Ajman UnoverCity Gis App\DycryptPSWD\DycryptPSWD\DecryptPswd.aspx.cs    Line: 77 

 <asp:GridView ID="gvUsers" runat="server" AutoGenerateColumns="false" HeaderStyle-BackColor="#3AC0F2"
    HeaderStyle-ForeColor="White" RowStyle-BackColor="#A1DCF2" OnRowDataBound = "OnRowDataBound">
    <Columns>
        <asp:BoundField DataField="Username" HeaderText="Username" />
        <asp:BoundField DataField="Password" HeaderText="Encrypted Password" />
        <asp:BoundField DataField="Password" HeaderText="Desrypted Password" />
    </Columns>
</asp:GridView>



using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Security.Cryptography;

namespace DycryptPSWD
{
    public partial class DecryptPswd : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!this.IsPostBack)
            {
                string constr = ConfigurationManager.ConnectionStrings["conString2"].ConnectionString;
                using (SqlConnection con = new SqlConnection(constr))
                {
                    using (SqlCommand cmd = new SqlCommand("SELECT * FROM Users"))
                    {
                        using (SqlDataAdapter sda = new SqlDataAdapter())
                        {
                            DataTable dt = new DataTable();
                            cmd.CommandType = CommandType.Text;
                            cmd.Connection = con;
                            sda.SelectCommand = cmd;
                            sda.Fill(dt);
                            gvUsers.DataSource = dt;
                            gvUsers.DataBind();
                        }
                    }
                }
            }
        }
        private string Encrypt(string clearText)
        {
            string EncryptionKey = "MAKV2SPBNI96703";
            byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
            using (Aes encryptor = Aes.Create())
            {
                Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
                encryptor.Key = pdb.GetBytes(32);
                encryptor.IV = pdb.GetBytes(16);
                using (MemoryStream ms = new MemoryStream())
                {
                    using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(clearBytes, 0, clearBytes.Length);
                        cs.Close();
                    }
                    clearText = Convert.ToBase64String(ms.ToArray());
                }
            }
            return clearText;
        }

        private string Decrypt(string cipherText)
        {
            string EncryptionKey = "MAKV2SPBNI96703";
            byte[] cipherBytes = Convert.FromBase64String(cipherText);
            using (Aes encryptor = Aes.Create())
            {
                Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
                encryptor.Key = pdb.GetBytes(32);
                encryptor.IV = pdb.GetBytes(16);
                using (MemoryStream ms = new MemoryStream())
                {
                    using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(cipherBytes, 0, cipherBytes.Length);
                        cs.Close();
                    }
                    cipherText = Encoding.Unicode.GetString(ms.ToArray());
                }
            }
            return cipherText;
        }

        protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                e.Row.Cells[2].Text = Decrypt(e.Row.Cells[2].Text);
            }
        }
    }
}