xml signature DS prefix?

Question

Is there a way to sign an XML file with RSA and to have the namespace prefix "ds:Signature" instead of "Signature"? I spent many hourstrying to solve this and from what I can see there is no solution.

It seems that it is hard-coded in the class System.Security.Cryptography.Xml.Signature.

XmlElement element = document.CreateElement("Signature", "http://www.w3.org/2000/09/xmldsig#");

If anyone knows a solution, I need to sign it like that cause the software importing it verifies it with "ds:signature", so with "ds" prefix the software verifies it like this:

    public static bool VerifySignature(XmlDocument doc, RSA key, string prefix)
    {
        SignedXml xml = new SignedXml(doc);
        string str = "Signature";
        if (!string.IsNullOrEmpty(prefix))
        {
            str = string.Format("{0}:{1}", prefix, str);
        }
        XmlNodeList elementsByTagName = doc.GetElementsByTagName(str);
        xml.LoadXml((XmlElement)elementsByTagName[0]);
        return xml.CheckSignature(key);
    }

  VerifySignature(xmlDoc, rsa, "ds");

normally it signs like this:

<kk>blabla<Signature xmlns="http://www.w3.org/2000/09/xmldsig#"><SignedInfo><CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" /><SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" /><Reference URI=""><Transforms><Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" /></Transforms><DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" /><DigestValue>rVL2nKjPTBhL9IDHYpu69OiE8gI=</DigestValue></Reference></SignedInfo><SignatureValue>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</SignatureValue></Signature></kk>

and I need it to do it like this:

<kk>blabla<ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"><ds:SignedInfo><ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" /><ds:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" /><ds:Reference URI=""><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" /></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" /><ds:DigestValue>rVL2nKjPTBhL9IDHYpu69OiE8gI=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>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</ds:SignatureValue></ds:Signature></kk>

Answer 1

if anyone know a solution, i need to sign it like that cause the software importing it verifies it with "ds:signature" , so with "ds" prefix

The prefix should be unimportant - all that should matter is what namespace the element is in. It shouldn't matter how that namespace is expressed. If it does, that shows brokenness in the verifying code, I'd say.

However, if you really want to do this, is there any reason you don't want to just replace the element with one with the same contents, but using the prefix you want? It shouldn't be hard to do that in LINQ to XML.