URL Encryption is not working

#Region "Using"
 Imports System.IO
Imports System.Web
Imports System.Text
Imports System.Security.Cryptography

#End Region

''' <summary>
''' Summary description for QueryStringEncryptDecryptModule
'''www.technade.com/2011/02/query-string-encryption-using-http.html
''' </summary>

Namespace Technade.Web.Core.Application
    Public Class EncryptDecrypt
        Implements IHttpModule
#Region "IHttpModule Members"
         Public Sub Dispose() Implements IHttpModule.Dispose
            ' Nothing to dispose
        End Sub

        Public Sub Init(ByVal context As HttpApplication) Implements IHttpModule.Init
            AddHandler context.BeginRequest, New EventHandler(AddressOf context_BeginRequest)
        End Sub

#End Region

        Private Const PARAMETER_NAME As String = "Technade="
        Private Const ENCRYPTION_KEY As String = "key"

        Private Sub context_BeginRequest(ByVal sender As Object, ByVal e As EventArgs)
            Dim context As HttpContext = HttpContext.Current
            If context.Request.Url.OriginalString.Contains("aspx") AndAlso context.Request.RawUrl.Contains("?") Then
                Dim query As String = ExtractQuery(context.Request.RawUrl)
                Dim path As String = GetVirtualPath()

                If query.StartsWith(PARAMETER_NAME, StringComparison.OrdinalIgnoreCase) Then
                    ' Decrypts the query string and rewrites the path.
                    Dim rawQuery As String = query.Replace(PARAMETER_NAME, String.Empty)
                    Dim decryptedQuery As String = Decrypt(rawQuery)
                    context.RewritePath(path, String.Empty, decryptedQuery)
                ElseIf context.Request.HttpMethod = "GET" Then
                    ' Encrypt the query string and redirects to the encrypted URL.
                    ' Remove if you don't want all query strings to be encrypted automatically.
                    Dim encryptedQuery As String = Encrypt(query)
                    context.Response.Redirect(path & encryptedQuery)
                End If
            End If
        End Sub

        ''' <summary>
        ''' Parses the current URL and extracts the virtual path without query string.
        ''' </summary>
        ''' <returns>The virtual path of the current URL.</returns>
        Private Shared Function GetVirtualPath() As String
            Dim path As String = HttpContext.Current.Request.RawUrl
            path = path.Substring(0, path.IndexOf("?"))
            path = path.Substring(path.LastIndexOf("/") + 1)
            Return path
        End Function

        ''' <summary>
        ''' Parses a URL and returns the query string.
        ''' </summary>
        ''' <param name="url">The URL to parse.</param>
        ''' <returns>The query string without the question mark.</returns>
        Private Shared Function ExtractQuery(ByVal url As String) As String
            Dim index As Integer = url.IndexOf("?") + 1
            Return url.Substring(index)
        End Function

#Region "Encryption/decryption"
         ''' <summary>
        ''' The salt value used to strengthen the encryption.
        ''' </summary>
        Private Shared ReadOnly SALT As Byte() = Encoding.ASCII.GetBytes(ENCRYPTION_KEY.Length.ToString())

        ''' <summary>
        ''' Encrypts any string using the Rijndael algorithm.
        ''' </summary>
        ''' <param name="inputText">The string to encrypt.</param>
        ''' <returns>A Base64 encrypted string.</returns>
        Public Shared Function Encrypt(ByVal inputText As String) As String
            Dim rijndaelCipher As New RijndaelManaged()
            Dim plainText As Byte() = Encoding.Unicode.GetBytes(inputText)
            Dim SecretKey As New PasswordDeriveBytes(ENCRYPTION_KEY, SALT)

            Using encryptor As ICryptoTransform = rijndaelCipher.CreateEncryptor(SecretKey.GetBytes(32), SecretKey.GetBytes(16))
                Using memoryStream As New MemoryStream()
                    Using cryptoStream As New CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write)
                        cryptoStream.Write(plainText, 0, plainText.Length)
                        cryptoStream.FlushFinalBlock()
                        Return "?" & PARAMETER_NAME & Convert.ToBase64String(memoryStream.ToArray())
                    End Using
                End Using
            End Using
        End Function

        ''' <summary>
        ''' Decrypts a previously encrypted string.
        ''' </summary>
        ''' <param name="inputText">The encrypted string to decrypt.</param>
        ''' <returns>A decrypted string.</returns>
        Public Shared Function Decrypt(ByVal inputText As String) As String
            Dim rijndaelCipher As New RijndaelManaged()
            Dim encryptedData As Byte() = Convert.FromBase64String(inputText)
            Dim secretKey As New PasswordDeriveBytes(ENCRYPTION_KEY, SALT)

            Using decryptor As ICryptoTransform = rijndaelCipher.CreateDecryptor(secretKey.GetBytes(32), secretKey.GetBytes(16))
                Using memoryStream As New MemoryStream(encryptedData)
                    Using cryptoStream As New CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read)
                        Dim plainText As Byte() = New Byte(encryptedData.Length - 1) {}
                        Dim decryptedCount As Integer = cryptoStream.Read(plainText, 0, plainText.Length)
                        Return Encoding.Unicode.GetString(plainText, 0, decryptedCount)
                    End Using
                End Using
            End Using
        End Function

#End Region
    End Class


End Namespace

<httpModules>
             <add name="EncryptDecryptModule" type=" Technade.Web.Core.Application.EncryptDecrypt"/>
           </httpModules>