xml file to memorystream to xmldocument

[inzo21]

Hello all,

 

the predicament for the evening.

 

I have a well formed xml file used for configuration in an application. I want to decrypt/encrypt this file when it gets used - thus when the app loads it decrypts and loads the contents in an xmldocument - when the app exists it encrypts and saves the contents back to the file. I figured this would involve the following pseudo-code.

 

on app load

1. read file into a byte array

2. run byte array through class.decryptfunction - returns another byte array

3. read returned byte array into memory stream

4. serialize memorystream into well-formed xml doc

5. load memorystream into xmldocument object for processing

 

without any encryption, I tried declaring an array of bytes and loading the contents of the xmldoc into this array. I then created a memorystream and read the contents of the byte array into that stream. I finally tried load the memorystram into the xmldocument.

 

Try

Dim mymem As MemoryStream = New MemoryStream

Dim ar() As Byte = PrepFile(FileLocation)

 

mymem.Write(ar, 0, ar.Length)

 

Console.WriteLine("byte ar: " & mymem.Length)

configfile.Load(mymem)

Console.WriteLine(configfile.OuterXml)

Catch e As Exception

Console.WriteLine("Exception: {0}", e.ToString())

End Try

 

the array and mem stream have data - but I receive an XMLException - root element missing. I'm guessing that this has something to do with serialization.

 

Does anyone have any ideas how to accomplish this or can they point me to a good article or two.

 

thanks,

 

inzo

[PlausiblyDamp]

You may find http://www.xtremedotnettalk.com/showthread.php?t=87175&highlight=encryption has some useful information.

[inzo21]

Still not working.

 

Okay - I took a look at the article you suggested PDamp and got some things out of it. I came up with the following test mod - which still isn't functioning.

 

Module Module1

 

Sub Main()

 

Dim cryptoprovider As RijndaelManaged = New RijndaelManaged

Dim key As Byte() = {11, 2, 7, 24, 16, 22, 4, 38, 27, 3, 11, 10, 17, 15, 6, 23}

Dim iv As Byte() = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}

Dim xtw As XmlTextWriter

Dim filename As String = "c:\testing\test.xml"

 

Dim FileWriter As FileStream = New FileStream(filename, FileMode.Create)

 

Dim CryptoWriter As CryptoStream = New CryptoStream(FileWriter, cryptoprovider.CreateEncryptor(key, iv), CryptoStreamMode.Write)

xtw = New XmlTextWriter(CryptoWriter, System.Text.Encoding.UTF8)

'FileWriter.Close()

 

Console.WriteLine("File Encrypted")

Console.ReadLine()

xtw.Close()

 

Dim FileReader As FileStream = New FileStream(filename, FileMode.Open)

Dim CryptoReader As CryptoStream = New CryptoStream(FileReader, cryptoprovider.CreateDecryptor(key, iv), CryptoStreamMode.Read)

'FileReader.Close()

 

Dim XmlDoc As XmlDocument = New XmlDocument

Dim XmlReader As XmlTextReader = New XmlTextReader(CryptoReader)

 

Try

XmlDoc.Load(XmlReader)

Console.WriteLine("file..............")

Console.WriteLine(XmlDoc.OuterXml.ToString)

Console.ReadLine()

Catch ex As XmlException

Console.WriteLine(ex.ToString)

Console.ReadLine()

 

End Try

 

End Sub

 

End Module

 

I get a system.xml.xmlexception - the root element is missing error.

 

The file is being encrypted but it seems that either the decryption is not working or there is garbage going in there that I can't parse out.

 

Any ideas?

 

inzo