Query string module encryption not working - asp.net

Question

I did the query string encryption of my project using the example provided here.
When I run the project locally it works fine:
But when I publish it to my server, the encryption simply doesn't work.
The application on the server is running on Windows Server 2008 R2 and IIS 7.
Maybe there is something I must change on IIS? I have no clue.
Anyone?
Thank you.
EDIT:
Here is the code of the QueryStringModule class:
Imports System
Imports System.IO
Imports System.Web
Imports System.Text
Imports System.Security.Cryptography
''' <summary>
''' Summary description for QueryStringModule
''' </summary>
Public Class QueryStringModule
Implements IHttpModule
#Region "IHttpModule Members"
Sub Init(context As HttpApplication) Implements System.Web.IHttpModule.Init
AddHandler context.BeginRequest, AddressOf context_BeginRequest
End Sub
Sub Dispose() Implements System.Web.IHttpModule.Dispose
' Nothing to dispose
End Sub
#End Region
Private Const PARAMETER_NAME As String = "enc="
Private Const ENCRYPTION_KEY As String = "key"
Private Sub context_BeginRequest(sender As Object, 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(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(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(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

Answer 1

Yes it's a ISS configuration issue.
The web.config for ISS 5 or 6 should contain a <httpModules> tag as is described on madskristensen.net.
<system.web>
<httpModules>
<add type="QueryStringModule" name="QueryStringModule"/>
</httpModules>
</system.web>
If your web application is running on IIS 7 then the setting should be in:
<system.webServer>
<modules>
<add type="QueryStringModule" name="QueryStringModule"/>
</modules>
</system.webServer>
This solution is also described here.

Answer 2

I just found a solution:
1-Open IIS on the server;
2-Select the desired web site;
3-Select Modules;
4-Right click then "Add managed modules";
5-Give a name to it and then find the module you you want to add in the dropdownlist;
6-Reset IIS.