private static (XDocument document, byte[] signature) GetSignatureToTimestamp(OpcPart signaturePart)
{
XNamespace xmlDSigNamespace = OpcKnownUris.XmlDSig.AbsoluteUri;
using (var signatureStream = signaturePart.Open())
{
var doc = XDocument.Load(signatureStream);
var signature = doc.Element(xmlDSigNamespace + "Signature")?.Element(xmlDSigNamespace + "SignatureValue")?.Value?.Trim();
return(doc, Convert.FromBase64String(signature));
}
}
public static (byte[] digest, Uri identifier) Digest(OpcPart part, HashAlgorithmName algorithmName)
{
using (var hashAlgorithm = HashAlgorithmTranslator.TranslateFromNameToxmlDSigUri(algorithmName, out var identifier))
{
using (var partStream = part.Open())
{
var digest = hashAlgorithm.ComputeHash(partStream);
return(digest, identifier);
}
}
}
public static (byte[] digest, Uri identifier) Digest(OpcPart part, HashAlgorithmName algorithmName)
{
var info = new HashAlgorithmInfo(algorithmName);
using (var hashAlgorithm = info.Create())
{
using (var partStream = part.Open())
{
var digest = hashAlgorithm.ComputeHash(partStream);
return(digest, info.XmlDSigIdentifier);
}
}
}
private static void PublishSignature(XmlDocument document, OpcPart signatureFile)
{
using (var copySignatureStream = signatureFile.Open())
{
copySignatureStream.SetLength(0L);
using (var xmlWriter = new XmlTextWriter(copySignatureStream, System.Text.Encoding.UTF8))
{
//The .NET implementation of OPC used by Visual Studio does not tollerate "white space" nodes.
xmlWriter.Formatting = Formatting.None;
document.Save(xmlWriter);
}
}
}
private static void ApplyTimestamp(XDocument originalSignatureDocument, OpcPart signaturePart, byte[] timestampSignature)
{
XNamespace xmlDSigNamespace = OpcKnownUris.XmlDSig.AbsoluteUri;
XNamespace xmlSignatureNamespace = OpcKnownUris.XmlDigitalSignature.AbsoluteUri;
var document = new XDocument(originalSignatureDocument);
var signature = new XElement(xmlDSigNamespace + "Object",
new XElement(xmlSignatureNamespace + "TimeStamp", new XAttribute("Id", "idSignatureTimestamp"),
new XElement(xmlSignatureNamespace + "Comment", ""),
new XElement(xmlSignatureNamespace + "EncodedTime", Convert.ToBase64String(timestampSignature))
)
);
document.Element(xmlDSigNamespace + "Signature").Add(signature);
using (var copySignatureStream = signaturePart.Open())
{
using (var xmlWriter = new XmlTextWriter(copySignatureStream, System.Text.Encoding.UTF8))
{
//The .NET implementation of OPC used by Visual Studio does not tollerate "white space" nodes.
xmlWriter.Formatting = Formatting.None;
document.Save(xmlWriter);
}
}
}