Sign XML with digital signature

Question

I'm working with some web-service which requires digitally signed XML to be posted via HTTP post request.
They gave me only one file (key.dat) which I should apply to my XML.
How can I do it?

Answer 1

You can take a look over here :

private static XmlElement GetXmlDigitalSignature(XmlDocument x, AsymmetricAlgorithm key)
{
    var signedXml = new SignedXml(x) { SigningKey = key };
    var reference = new Reference { Uri = "", TransformChain = new TransformChain(), };

    reference.AddTransform(new XmlDsigEnvelopedSignatureTransform());

    signedXml.AddReference(reference);
    signedXml.ComputeSignature();

    return signedXml.GetXml();
}

var signature = GetXmlDigitalSignature(xmlDocument, algorithm);
xmlDocument.FirstChild.AppendChild(xmlDocument.ImportNode(signature, true));