// This method replaces an EncryptedData element with the decrypted sequence of bytes
public void ReplaceData(XmlElement inputElement, byte[] decryptedData)
{
if (inputElement == null)
{
throw new ArgumentNullException(nameof(inputElement));
}
if (decryptedData == null)
{
throw new ArgumentNullException(nameof(decryptedData));
}
XmlNode parent = inputElement.ParentNode;
if (parent.NodeType == XmlNodeType.Document)
{
// We're replacing the root element, but we can't just wholesale replace the owner
// document's InnerXml, since we need to preserve any other top-level XML elements (such as
// comments or the XML entity declaration. Instead, create a new document with the
// decrypted XML, import it into the existing document, and replace just the root element.
XmlDocument importDocument = new XmlDocument();
importDocument.PreserveWhitespace = true;
string decryptedString = _encoding.GetString(decryptedData);
using (StringReader sr = new StringReader(decryptedString))
{
using (XmlReader xr = XmlReader.Create(sr, Utils.GetSecureXmlReaderSettings(_xmlResolver)))
{
importDocument.Load(xr);
}
}
XmlNode importedNode = inputElement.OwnerDocument.ImportNode(importDocument.DocumentElement, true);
parent.RemoveChild(inputElement);
parent.AppendChild(importedNode);
}
else
{
XmlNode dummy = parent.OwnerDocument.CreateElement(parent.Prefix, parent.LocalName, parent.NamespaceURI);
try
{
parent.AppendChild(dummy);
// Replace the children of the dummy node with the sequence of bytes passed in.
// The string will be parsed into DOM objects in the context of the parent of the EncryptedData element.
dummy.InnerXml = _encoding.GetString(decryptedData);
// Move the children of the dummy node up to the parent.
XmlNode child = dummy.FirstChild;
XmlNode sibling = inputElement.NextSibling;
XmlNode nextChild = null;
while (child != null)
{
nextChild = child.NextSibling;
parent.InsertBefore(child, sibling);
child = nextChild;
}
}
finally
{
// Remove the dummy element.
parent.RemoveChild(dummy);
}
// Remove the EncryptedData element
parent.RemoveChild(inputElement);
}
}