/// <summary>
/// Signs the XML document.
/// </summary>
/// <param name="doc">The document.</param>
/// <param name="certificate">The certificate.</param>
/// <param name="referenceUri">The reference URI.</param>
/// <param name="signatureMethod">The signature method.</param>
/// <param name="digestMethod">The digest method.</param>
/// <returns></returns>
/// <exception cref="FieldAccessException"></exception>
internal static XmlElement SignXMLDoc(XmlDocument doc,
X509Certificate2 certificate,
string referenceUri,
string signatureMethod,
string digestMethod)
{
BusinessValidation.ValidationNotNull(doc, ErrorLocalization.XmlDocNull);
BusinessValidation.ValidationNotNull(certificate, ErrorLocalization.CertificateNull);
BusinessValidation.ValidationNotNullNotWhitespace(referenceUri, ErrorLocalization.ReferenceUriNullOrWhitespace);
AsymmetricAlgorithm privateKey;
try
{
privateKey = certificate.PrivateKey;
}
catch (Exception ex)
{
throw new FieldAccessException(ErrorLocalization.PrivateKeyNotFound, ex);
}
SignedXml signedXml = new SignedXml(doc)
{
SigningKey = privateKey
};
signedXml.SignedInfo.SignatureMethod = signatureMethod;
signedXml.SignedInfo.CanonicalizationMethod = SignedXml.XmlDsigExcC14NTransformUrl;
Reference reference = new Reference
{
DigestMethod = digestMethod,
Uri = "#" + referenceUri
};
reference.AddTransform(new XmlDsigEnvelopedSignatureTransform());
reference.AddTransform(new XmlDsigExcC14NTransform());
signedXml.AddReference(reference);
KeyInfo keyInfo = new KeyInfo();
keyInfo.AddClause(new KeyInfoX509Data(certificate));
signedXml.KeyInfo = keyInfo;
signedXml.ComputeSignature();
return(signedXml.GetXml());
}
/// <summary>
/// Verifies the signature.
/// </summary>
/// <param name="signedDocument">The signed document.</param>
/// <param name="xmlMetadata">The XML metadata.</param>
/// <returns></returns>
internal static bool VerifySignature(XmlDocument signedDocument, XmlDocument xmlMetadata = null)
{
BusinessValidation.Argument(signedDocument, string.Format(ErrorLocalization.ParameterCantNullOrEmpty, nameof(signedDocument)));
try
{
SignedXml signedXml = new SignedXml(signedDocument);
if (xmlMetadata is not null)
{
XmlNodeList MetadataNodeList = xmlMetadata.SelectNodes("//*[local-name()='Signature']");
SignedXml signedMetadataXml = new SignedXml(xmlMetadata);
signedMetadataXml.LoadXml((XmlElement)MetadataNodeList[0]);
var x509dataMetadata = signedMetadataXml.Signature.KeyInfo.OfType <KeyInfoX509Data>().First();
var publicMetadataCert = x509dataMetadata.Certificates[0] as X509Certificate2;
XmlNodeList nodeList = (signedDocument.GetElementsByTagName("ds:Signature")?.Count > 1) ?
signedDocument.GetElementsByTagName("ds:Signature") :
(signedDocument.GetElementsByTagName("ns2:Signature")?.Count > 1) ?
signedDocument.GetElementsByTagName("ns2:Signature") :
signedDocument.GetElementsByTagName("Signature");
signedXml.LoadXml((XmlElement)nodeList[0]);
return(signedXml.CheckSignature(publicMetadataCert, true));
}
else
{
XmlNodeList nodeList = (signedDocument.GetElementsByTagName("ds:Signature")?.Count > 0) ?
signedDocument.GetElementsByTagName("ds:Signature") :
signedDocument.GetElementsByTagName("Signature");
foreach (var node in nodeList)
{
signedXml.LoadXml((XmlElement)node);
if (!signedXml.CheckSignature())
{
return(false);
}
}
return(true);
}
}
catch (Exception)
{
return(false);
}
}
