private static bool VerifySignature(XmlDocument xmlDocument, X509Certificate2 cert)
{
var signedXml = new SignedXmlWithIdResolvement(xmlDocument);
var nodeList = xmlDocument.GetElementsByTagName("Signature", "http://www.w3.org/2000/09/xmldsig#");
if (nodeList.Count == 0)
{
throw new InvalidOperationException("Document does not contain a signature to verify.");
}
signedXml.LoadXml((XmlElement)nodeList[0]);
return(signedXml.CheckSignature(cert, true));
}
/// <summary>
/// Signs an XmlDocument with an xml signature using the signing certificate given as argument to the method.
/// In case it is ever needed ... this link explains how to add namespace prefixes to the generated signature. http://stackoverflow.com/questions/12219232/xml-signature-ds-prefix
/// </summary>
/// <param name="xDoc">The XDocument to be signed</param>
/// <param name="ids">The ids of the elements in the xmldocument that must be signed.</param>
/// <param name="cert">The certificate used to sign the document</param>
public static XDocument SignDocument(XDocument xDoc, IEnumerable <string> ids, X509Certificate2 cert)
{
// Convert to XmlDocument as SignedXml only understands this type.
var doc = ToXmlDocument(xDoc);
// Apply private key, canonicalization method and signature method
var signedXml = new SignedXmlWithIdResolvement(doc);
signedXml.SignedInfo.CanonicalizationMethod = SignedXml.XmlDsigExcC14NTransformUrl;
signedXml.SignedInfo.SignatureMethod = RsaPkcs1Sha256SignatureDescription.XmlDsigMoreRsaSha256Url;
signedXml.SigningKey = cert.PrivateKey;
// Make a reference for each element that must be signed.
foreach (var id in ids)
{
var reference = new Reference("#" + id);
reference.AddTransform(new XmlDsigExcC14NTransform());
reference.DigestMethod = RsaPkcs1Sha256SignatureDescription.XmlEncSha256Url;
signedXml.AddReference(reference);
}
// Include a reference to the certificate
var referenceElement = doc.CreateElement(SignatureCaseMessageTransformer.WssePrefix,
"Reference",
SignatureCaseMessageTransformer.Wsse10Namespace);
referenceElement.SetAttribute("URI", "#sec-binsectoken"); // Attribute must be in the empty namespace.
var securityTokenReferenceElement = doc.CreateElement(SignatureCaseMessageTransformer.WssePrefix, "SecurityTokenReference",
SignatureCaseMessageTransformer.Wsse10Namespace);
securityTokenReferenceElement.AppendChild(referenceElement);
signedXml.KeyInfo.AddClause(new KeyInfoNode(securityTokenReferenceElement));
signedXml.ComputeSignature();
// Append the computed signature. The signature must be placed as the sibling of the BinarySecurityToken element.
var nsManager = new XmlNamespaceManager(doc.NameTable);
nsManager.AddNamespace(SignatureCaseMessageTransformer.S11Prefix, SignatureCaseMessageTransformer.S11Namespace);
nsManager.AddNamespace(SignatureCaseMessageTransformer.WssePrefix, SignatureCaseMessageTransformer.Wsse10Namespace);
var securityNode = doc.SelectSingleNode("/" + SignatureCaseMessageTransformer.S11Prefix + ":Envelope/" + SignatureCaseMessageTransformer.S11Prefix + ":Header/" + SignatureCaseMessageTransformer.WssePrefix + ":Security", nsManager);
var binarySecurityTokenNode = doc.SelectSingleNode("/" + SignatureCaseMessageTransformer.S11Prefix + ":Envelope/" + SignatureCaseMessageTransformer.S11Prefix + ":Header/" + SignatureCaseMessageTransformer.WssePrefix + ":Security/" + SignatureCaseMessageTransformer.WssePrefix + ":BinarySecurityToken", nsManager);
securityNode.InsertAfter(doc.ImportNode(signedXml.GetXml(), true), binarySecurityTokenNode);
var signedDocument = ToXDocument(doc);
return(signedDocument);
}