5

Following my questions about storing data, it has been suggested that I could use XML but then obfuscate the file by encoding it using Base64. I like this idea, and I have achieved what I want in XML, but I don't know how to save it in Base64. This is my code so far:

XmlWriterSettings settings = new XmlWriterSettings();
settings.Indent = true;

XmlWriter write = XmlWriter.Create("C:\\Users\\Andy\\Desktop\\database.xml", settings);
write.WriteStartDocument();
write.WriteStartElement("Database");
write.WriteStartElement("Entry");
write.WriteAttributeString("key", "value");
write.WriteEndElement();
write.WriteEndElement();

write.Flush();
write.Close();
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4 Answers 4

Reset to default
6

Write it:

var sb = new StringBuilder(); 
var settings = new XmlWriterSettings();
//..settings
using (var writer = XmlWriter.Create(sb, settings))
{
    //...
}
//http://stackoverflow.com/questions/1564718/using-stringwriter-for-xml-serialization
var encoding = new UnicodeEncoding(); 
string s = Convert.ToBase64String(encoding.GetBytes(sb.ToString()));

File.WriteAllText("c:\temp.txt", s);

Read it:

string readText = File.ReadAllText("c:\temp.txt");
byte[] toDecodeByte = Convert.FromBase64String(readText);

using (var stream = new MemoryStream(toDecodeByte))
{
    using (XmlReader reader = XmlReader.Create(stream))
    {
        //.. read your xml
    }
}
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26 Comments

Thank you for your answer. I would like to encode the entire XML file though, so could you please expand on that part.
+1 Thank you for the edit. So would I then just use a writer object to write s to a file? Also, I know I didn't ask it originally but could you show me how to read the XML file as well please?
Please do not use ASCIIEncoding. You should use UTF8Encoding.
@Andy: You CAN include non-ASCII characters in the XML, regardless of whether you use ASCII or UTF8 when writing the base64 string. As was pointed out, base64 encodes binary data using only ASCII characters--that's the whole point of it. When it's decoded, you get back the original binary data.
@Andy: Compression and/or any non-trivial encryption (anything beyond a simple substitution cipher) will be slower than base64 encoding. base64 encoding is a very simple transformation. It will take longer to write the encoded string to disk than it takes to encode the string.
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3

You need to convert your xmlwriter to string like this

 using (var sw = new StringWriter()) {
 using (var xw = XmlWriter.Create(sw)) {
// Build Xml with xw.


   }
  return sw.ToString();
}

then convert your string to Base64. and write it to file

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4 Comments

Thank you for your answer. So I would I then have to create a new writer object for the Base64 encoded data?
+1. You should add the code that shows how to convert the returned string to base64 and write it to file.
@EhsanUllah Yes, please do :)
@EhsanUllah Yeah I have now thank you. It's ok, thank you for your help though.
1

This will have the information that you are looking for:

http://msdn.microsoft.com/en-us/library/system.xml.xmlwriter.writebase64.aspx

HTH,

d3

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2 Comments

Thanks for your answer but I want to encode the entire XML file rather than just the values.
That's only good for writing specific binary data. That won't base64 encode the entire XML file.
1

Here is an example using a MemoryStream

Save the XML data using MemoryStream to base64 encode the data and write it to a file.

using (var ms = new MemoryStream())
{   
    // Memory Stream
    using (XmlWriter writer = XmlWriter.Create(ms,settings)) 
    {
        writer.WriteStartDocument();
        writer.WriteStartElement("Database");
        writer.WriteStartElement("Entry");
        writer.WriteAttributeString("key", "value");
        writer.WriteEndElement();
        writer.WriteEndElement();

        writer.Flush();
        writer.Close();

        // XML Data (Debug)
        Console.WriteLine(new UTF8Encoding().GetString(ms.ToArray()));

        // Pre encoding hex (Debug)
        Console.WriteLine(BitConverter.ToString(ms.ToArray()));

        string s = Convert.ToBase64String(ms.ToArray());
        Console.WriteLine(s); // (Debug)

        // Post encoding
        File.WriteAllText(@"C:\Temp\A.enc", s);
    }
}

Read the file back

// Read encoded file back to xml
string enc_text = File.ReadAllText(@"C:\Temp\A.enc");
Console.WriteLine(enc_text); // (Debug)

// Pre encoding hex
byte[] mem_bytes = Convert.FromBase64String(enc_text);
Console.WriteLine(BitConverter.ToString(mem_bytes)); // (Debug)

// XML Data
Console.WriteLine(new UTF8Encoding().GetString(mem_bytes));

// Read byte array into Reader
using (var stream = new MemoryStream(mem_bytes))
{
    using (XmlReader reader = XmlReader.Create(stream))
    {
        // Use reader as desired
    }
}
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3 Comments

Thank you very much for your answer. Regarding reading the file back, how could I actually get the data in the XmlReader rather than just print it? Which Stream object would be best to use?
@Andy - I updated to show how to create the XmlReader from the byte array data.
Thank you very much. I thought it would be something like that, but I'm very new to C#.

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