String digestMethod;
        String signMethod;
        String res = "";
        try {

            if (privateKey.getAlgorithm().toUpperCase().compareTo("ECGOST34310") == 0)
            {
                signMethod = "http://www.w3.org/2001/04/xmldsig-more#gost34310-gost34311";
                digestMethod = "http://www.w3.org/2001/04/xmldsig-more#gost34311";
            }
            else
            {
                signMethod = "http://www.w3.org/2001/04/xmldsig-more#rsa-sha256";
                digestMethod = "http://www.w3.org/2001/04/xmlenc#sha256";
            }

            XMLSignature sig = new XMLSignature(doc, "", signMethod);
            if (doc.getFirstChild() != null) {

                doc.getFirstChild().appendChild(sig.getElement());
                Transforms transforms = new Transforms(doc);
                transforms.addTransform("http://www.w3.org/2000/09/xmldsig#enveloped-signature");
                transforms.addTransform("http://www.w3.org/TR/2001/REC-xml-c14n-20010315#WithComments");
              
                StringWriter oss = new StringWriter();
                TransformerFactory tff = TransformerFactory.newInstance();
                Transformer transs = tff.newTransformer();
                transs.transform(new DOMSource(transforms.getDocument()), new StreamResult(oss));
                oss.close();
                System.out.println("----------------TRANSFORMED-----------------");
                System.out.println(oss.toString());


                sig.addDocument("", transforms, digestMethod);
                sig.addKeyInfo((X509Certificate) cert);
                sig.sign(privateKey);

                StringWriter os = new StringWriter();
                TransformerFactory tf = TransformerFactory.newInstance();
                Transformer trans = tf.newTransformer();
                trans.transform(new DOMSource(doc), new StreamResult(os));
                os.close();
                res = os.toString();
            }
            System.out.println(new String(sig.getSignedInfo().getCanonicalizedOctetStream(),"UTF-8"));
            System.out.println("----------------------------------------------");
            return res;

<tag1   >value</tag1>

<p:DataType xsi:type="p:DataType" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:co="coURI" xmlns:p="pURI">

 Canonicalizer canon = Canonicalizer.getInstance(Canonicalizer.ALGO_ID_C14N_WITH_COMMENTS);
            byte[] canBytes = canon.canonicalize(fileBytes);
            System.out.println("ALGO_ID_C14N_WITH_COMMENTS");
            System.out.println(new String(canBytes,"UTF-8"));
            System.out.println("----------------------------------------------");

<p:DataType xmlns:co="coURI" xmlns:p="pURI" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="p:DataType">

<p:DataType xmlns:p="pURI" xmlns:co="coURI" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="p:DataType">