// Sign an XML file and save the signature in a new file. This method does not
// save the public key within the XML file. This file cannot be verified unless
// the verifying code has the key with which it was signed.
public static void SignXmlFile(string FileName, string SignedFileName)
{
// Create a new XML document.
XmlDocument doc = new XmlDocument();
// Load the passed XML file using its name.
doc.Load(new XmlTextReader(FileName));
// Create a SignedXml object.
KeyVaultSignedXml signedXml = new KeyVaultSignedXml(doc);
// Create a reference to be signed.
Reference reference = new Reference();
reference.Uri = "";
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform env = new XmlDsigEnvelopedSignatureTransform();
reference.AddTransform(env);
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
// Compute the signature.
signedXml.ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, true));
if (doc.FirstChild is XmlDeclaration)
{
doc.RemoveChild(doc.FirstChild);
}
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false));
doc.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file against an asymetric
// algorithm and return the result.
public static Boolean VerifyXmlFile(String Name)
{
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Load the passed XML file into the document.
xmlDocument.Load(Name);
// Create a new KeyVaultSignedXml object and pass it
// the XML document class.
KeyVaultSignedXml signedXml = new KeyVaultSignedXml(xmlDocument);
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature and return the result.
return(signedXml.CheckSignature());
}
