XML Decryption Bug (referencing issue)
- by OrangePekoe
Hi,
Needing some explanation of what exactly the decryption is doing, in addition to some help on solving the problem.
Currently, when a portion of XML is encrypted, and then decrypted, the DOM appears to work correctly. We can see the element is encrypted and then see it return back once it is decrypted. Our problem lies when a user tries to change data in that same element after decryption has occurred.
When a user changes some settings, data in the XML should change. However, if the user attempts to change an XML element that has been decrypted the changes are not reflected in the DOM.
We have a reference pointer to the XML element that is used to bind the element to an object. If you encrypt the node and then decrypt it, the reference pointer now points to a valid orphaned XML element that is no longer part of the DOM.
After decryption, there will be 2 copies of the XML element. One in the DOM as expected (though will not reflect new changes), and one orphaned element in memory that is still referenced by our pointer. The orphaned element is valid (reflects new changes). We can see that this orphaned element is owned by the DOM, but when we try to return its parent, it returns null.
The question is:
Where did this orphaned xml element come from? And how can we get it to correctly append (replace old data) to the DOM?
The code resembles:
public static void Decrypt(XmlDocument Doc, SymmetricAlgorithm Alg)
{
if (Doc == null)
throw new ArgumentNullException("Doc");
if (Alg == null)
throw new ArgumentNullException("Alg");
XmlElement encryptedElement = Doc.GetElementsByTagName("EncryptedData")[0] as XmlElement;
if (encryptedElement == null)
{
throw new XmlException("The EncryptedData element was not found.");
}
EncryptedData edElement = new EncryptedData();
edElement.LoadXml(encryptedElement);
EncryptedXml exml = new EncryptedXml();
byte[] rgbOutput = exml.DecryptData(edElement, Alg);
exml.ReplaceData(encryptedElement, rgbOutput);
}
