在生成数字签名之前，如何规范化 SignedInfo 节点？

问：

我想生成数字签名，但被告知我需要在生成之前先规范化 SignedInfo 节点。我被困在如何首先规范化节点上，并想知道是否可以基于以下代码：

            byte [] xmlstringbytes=null;
            xmlstringbytes= XMLStringWithNoSignature.getBytes("UTF-8");
            final List<Object> listkey= new LinkedList<Object> ();
            XMLSignatureFactory fac = XMLSignatureFactory.getInstance("DOM");
           //digest
            DigestMethod digestMethodObj = fac.newDigestMethod("http://www.w3.org/2001/04/xmlenc#sha256", null);
           //canon
            CanonicalizationMethod canonicalizationMethod = fac.newCanonicalizationMethod("http://www.w3.org/TR/2001/REC-xml-c14n-20010315", (C14NMethodParameterSpec) null);
            //signature
            SignatureMethod signatureMethodObj = fac.newSignatureMethod("http://www.w3.org/2001/04/xmldsig-more#rsa-sha256", null);
            
            //transform
            Transform transform1 = fac.newTransform("http://www.w3.org/2000/09/xmldsig#enveloped- 
            signature", (TransformParameterSpec) null);

            Transform transform2 = fac.newTransform("http://www.w3.org/2006/12/xml-c14n11", (TransformParameterSpec) null);

            List<Transform> transformList = new ArrayList<Transform>();
            transformList.add(transform1);
            transformList.add(transform2);

            //reference
            Reference ref = (Reference) fac.newReference("", digestMethodObj, transformList, null, null);
            List<Reference> referenceList = Collections.singletonList(ref);

            //keyinfo
            final KeyInfo keyInfo = keyInfoFactory.newKeyInfo (listkey);

           //signedinfo
            SignedInfo signedInfo = fac.newSignedInfo(canonicalizationMethod, signatureMethodObj, 
             referenceList);

            Document doc = dbf.newDocumentBuilder().parse(new ByteArrayInputStream(xmlstringbytes));
    
            DOMSignContext dsc = new DOMSignContext(Key, doc.getDocumentElement());

           //generate signature, will need to canonicalize signedInfo first before executing below 
             command
            XMLSignature xmlSignature = fac.newXMLSignature(signedInfo, keyInfo);
            xmlSignature.sign(dsc);

提前感谢您的输入。