javax.xml.crypto.XMLStructure Java Examples

private List getCertificateChainFromXML(List xmlElements) throws KeyStoreException {
    boolean found = false;
    List certs = null;
    for (int i = 0; i < xmlElements.size(); i++)
    {
        XMLStructure xmlStructure = (XMLStructure) xmlElements.get(i);
        if (xmlStructure instanceof X509Data)
        {
            if(found) throw new KeyStoreException("Duplicate X509Data element");
            found = true;
            certs = (List<X509Certificate>) ((X509Data) xmlStructure).getContent();
        }
    }
    return certs;
}
 

@Override
public KeySelectorResult select ( final KeyInfo keyInfo, final KeySelector.Purpose purpose, final AlgorithmMethod method, final XMLCryptoContext context ) throws KeySelectorException
{
    if ( keyInfo == null )
    {
        throw new KeySelectorException ( "Null KeyInfo object!" );
    }

    final SignatureMethod sm = (SignatureMethod)method;
    final List<?> list = keyInfo.getContent ();

    for ( final Object l : list )
    {
        final XMLStructure xmlStructure = (XMLStructure)l;
        if ( xmlStructure instanceof X509Data )
        {
            for ( final Object o : ( (X509Data)xmlStructure ).getContent () )
            {
                KeySelectorResult result = null;
                if ( o instanceof X509Certificate )
                {
                    result = findPublicKey ( (X509Certificate)o, sm );
                }

                if ( result != null )
                {
                    return result;
                }
            }
        }
    }
    throw new KeySelectorException ( "No KeyValue element found!" );
}
 

static void test_create_sign_spec() throws Exception {
        System.out.println("* Generating sign-spec.xml");
        List<Reference> refs = new ArrayList<Reference>(2);

        // create reference 1
        List<XPathType> types = new ArrayList<XPathType>(3);
        types.add(new XPathType(" //ToBeSigned ", XPathType.Filter.INTERSECT));
        types.add(new XPathType(" //NotToBeSigned ",
            XPathType.Filter.SUBTRACT));
        types.add(new XPathType(" //ReallyToBeSigned ",
            XPathType.Filter.UNION));
        XPathFilter2ParameterSpec xp1 = new XPathFilter2ParameterSpec(types);
        refs.add(fac.newReference
            ("", fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform(Transform.XPATH2, xp1)),
             null, null));

        // create reference 2
        List<Transform> trans2 = new ArrayList<Transform>(2);
        trans2.add(fac.newTransform(Transform.ENVELOPED,
            (TransformParameterSpec) null));
        XPathFilter2ParameterSpec xp2 = new XPathFilter2ParameterSpec
            (Collections.singletonList
                (new XPathType(" / ", XPathType.Filter.UNION)));
        trans2.add(fac.newTransform(Transform.XPATH2, xp2));
        refs.add(fac.newReference("#signature-value",
            fac.newDigestMethod(DigestMethod.SHA1, null), trans2, null, null));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(
            fac.newCanonicalizationMethod
                (CanonicalizationMethod.INCLUSIVE,
                 (C14NMethodParameterSpec) null),
            fac.newSignatureMethod(SignatureMethod.DSA_SHA1, null), refs);

        // create KeyInfo
        List<XMLStructure> kits = new ArrayList<XMLStructure>(2);
        kits.add(kifac.newKeyValue(validatingKey));
        List<Object> xds = new ArrayList<Object>(2);
        xds.add("CN=User");
        xds.add(signingCert);
        kits.add(kifac.newX509Data(xds));
        KeyInfo ki = kifac.newKeyInfo(kits);

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature
            (si, ki, null, null, "signature-value");

        Document doc = db.newDocument();
        Element tbs1 = doc.createElementNS(null, "ToBeSigned");
        Comment tbs1Com = doc.createComment(" comment ");
        Element tbs1Data = doc.createElementNS(null, "Data");
        Element tbs1ntbs = doc.createElementNS(null, "NotToBeSigned");
        Element tbs1rtbs = doc.createElementNS(null, "ReallyToBeSigned");
        Comment tbs1rtbsCom = doc.createComment(" comment ");
        Element tbs1rtbsData = doc.createElementNS(null, "Data");
        tbs1rtbs.appendChild(tbs1rtbsCom);
        tbs1rtbs.appendChild(tbs1rtbsData);
        tbs1ntbs.appendChild(tbs1rtbs);
        tbs1.appendChild(tbs1Com);
        tbs1.appendChild(tbs1Data);
        tbs1.appendChild(tbs1ntbs);

        Element tbs2 = doc.createElementNS(null, "ToBeSigned");
        Element tbs2Data = doc.createElementNS(null, "Data");
        Element tbs2ntbs = doc.createElementNS(null, "NotToBeSigned");
        Element tbs2ntbsData = doc.createElementNS(null, "Data");
        tbs2ntbs.appendChild(tbs2ntbsData);
        tbs2.appendChild(tbs2Data);
        tbs2.appendChild(tbs2ntbs);

        Element document = doc.createElementNS(null, "Document");
        document.appendChild(tbs1);
        document.appendChild(tbs2);
        doc.appendChild(document);

        DOMSignContext dsc = new DOMSignContext(signingKey, document);

        sig.sign(dsc);

//      dumpDocument(doc, new FileWriter("/tmp/foo.xml"));

        DOMValidateContext dvc = new DOMValidateContext
            (new KeySelectors.KeyValueKeySelector(), document.getLastChild());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }
        System.out.println();
    }
 

static void test_create_signature_reference_dependency() throws Exception {
        System.out.println("* Generating signature-reference-dependency.xml");
        // create references
        List<Reference> refs = Collections.singletonList
            (fac.newReference("#object-1", sha1));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(withoutComments, rsaSha1, refs);

        // create objects
        List<XMLStructure> objs = new ArrayList<XMLStructure>();

        // Object 1
        List<Reference> manRefs = Collections.singletonList
            (fac.newReference("#object-2", sha1));
        objs.add(fac.newXMLObject(Collections.singletonList
            (fac.newManifest(manRefs, "manifest-1")), "object-1", null, null));

        // Object 2
        Document doc = db.newDocument();
        Element nc = doc.createElementNS(null, "NonCommentandus");
        nc.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns", "");
        nc.appendChild(doc.createComment(" Commentandum "));
        objs.add(fac.newXMLObject(Collections.singletonList
            (new DOMStructure(nc)), "object-2", null, null));

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature(si, rsa, objs, "signature", null);
        DOMSignContext dsc = new DOMSignContext(getPrivateKey("RSA", 512), doc);

        sig.sign(dsc);

//      dumpDocument(doc, new PrintWriter(System.out));

        DOMValidateContext dvc = new DOMValidateContext
            (kvks, doc.getDocumentElement());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }

        System.out.println();
    }
 

static void test_create_exc_signature() throws Exception {
        System.out.println("* Generating exc_signature.xml");
        List<Reference> refs = new ArrayList<>(4);

        // create reference 1
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList
                (fac.newTransform(CanonicalizationMethod.EXCLUSIVE,
                 (TransformParameterSpec) null)),
             null, null));

        // create reference 2
        List<String> prefixList = new ArrayList<>(2);
        prefixList.add("bar");
        prefixList.add("#default");
        ExcC14NParameterSpec params = new ExcC14NParameterSpec(prefixList);
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList
                (fac.newTransform(CanonicalizationMethod.EXCLUSIVE, params)),
             null, null));

        // create reference 3
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform
                (CanonicalizationMethod.EXCLUSIVE_WITH_COMMENTS,
                 (TransformParameterSpec) null)),
             null, null));

        // create reference 4
        prefixList = new ArrayList<>(2);
        prefixList.add("bar");
        prefixList.add("#default");
        params = new ExcC14NParameterSpec(prefixList);
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform
                (CanonicalizationMethod.EXCLUSIVE_WITH_COMMENTS, params)),
             null, null));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(
            fac.newCanonicalizationMethod
                (CanonicalizationMethod.EXCLUSIVE,
                 (C14NMethodParameterSpec) null),
            fac.newSignatureMethod(SignatureMethod.DSA_SHA1, null), refs);

        // create KeyInfo
        List<XMLStructure> kits = new ArrayList<>(2);
        kits.add(kifac.newKeyValue(validatingKey));
        KeyInfo ki = kifac.newKeyInfo(kits);

        // create Objects
        Document doc = db.newDocument();
        Element baz = doc.createElementNS("urn:bar", "bar:Baz");
        Comment com = doc.createComment(" comment ");
        baz.appendChild(com);
        XMLObject obj = fac.newXMLObject(Collections.singletonList
            (new DOMStructure(baz)), "to-be-signed", null, null);

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature
            (si, ki, Collections.singletonList(obj), null, null);

        Element foo = doc.createElementNS("urn:foo", "Foo");
        foo.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns", "urn:foo");
        foo.setAttributeNS
            ("http://www.w3.org/2000/xmlns/", "xmlns:bar", "urn:bar");
        doc.appendChild(foo);

        DOMSignContext dsc = new DOMSignContext(signingKey, foo);
        dsc.putNamespacePrefix(XMLSignature.XMLNS, "dsig");

        sig.sign(dsc);

//      dumpDocument(doc, new FileWriter("/tmp/foo.xml"));

        DOMValidateContext dvc = new DOMValidateContext
            (new KeySelectors.KeyValueKeySelector(), foo.getLastChild());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }
        System.out.println();
    }
 

static void test_create_exc_signature() throws Exception {
        System.out.println("* Generating exc_signature.xml");
        List<Reference> refs = new ArrayList<Reference>(4);

        // create reference 1
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList
                (fac.newTransform(CanonicalizationMethod.EXCLUSIVE,
                 (TransformParameterSpec) null)),
             null, null));

        // create reference 2
        List<String> prefixList = new ArrayList<String>(2);
        prefixList.add("bar");
        prefixList.add("#default");
        ExcC14NParameterSpec params = new ExcC14NParameterSpec(prefixList);
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList
                (fac.newTransform(CanonicalizationMethod.EXCLUSIVE, params)),
             null, null));

        // create reference 3
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform
                (CanonicalizationMethod.EXCLUSIVE_WITH_COMMENTS,
                 (TransformParameterSpec) null)),
             null, null));

        // create reference 4
        prefixList = new ArrayList<String>(2);
        prefixList.add("bar");
        prefixList.add("#default");
        params = new ExcC14NParameterSpec(prefixList);
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform
                (CanonicalizationMethod.EXCLUSIVE_WITH_COMMENTS, params)),
             null, null));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(
            fac.newCanonicalizationMethod
                (CanonicalizationMethod.EXCLUSIVE,
                 (C14NMethodParameterSpec) null),
            fac.newSignatureMethod(SignatureMethod.DSA_SHA1, null), refs);

        // create KeyInfo
        List<XMLStructure> kits = new ArrayList<XMLStructure>(2);
        kits.add(kifac.newKeyValue(validatingKey));
        KeyInfo ki = kifac.newKeyInfo(kits);

        // create Objects
        Document doc = db.newDocument();
        Element baz = doc.createElementNS("urn:bar", "bar:Baz");
        Comment com = doc.createComment(" comment ");
        baz.appendChild(com);
        XMLObject obj = fac.newXMLObject(Collections.singletonList
            (new DOMStructure(baz)), "to-be-signed", null, null);

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature
            (si, ki, Collections.singletonList(obj), null, null);

        Element foo = doc.createElementNS("urn:foo", "Foo");
        foo.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns", "urn:foo");
        foo.setAttributeNS
            ("http://www.w3.org/2000/xmlns/", "xmlns:bar", "urn:bar");
        doc.appendChild(foo);

        DOMSignContext dsc = new DOMSignContext(signingKey, foo);
        dsc.putNamespacePrefix(XMLSignature.XMLNS, "dsig");

        sig.sign(dsc);

//      dumpDocument(doc, new FileWriter("/tmp/foo.xml"));

        DOMValidateContext dvc = new DOMValidateContext
            (new KeySelectors.KeyValueKeySelector(), foo.getLastChild());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }
        System.out.println();
    }
 

static void test_create_exc_signature() throws Exception {
        System.out.println("* Generating exc_signature.xml");
        List<Reference> refs = new ArrayList<Reference>(4);

        // create reference 1
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList
                (fac.newTransform(CanonicalizationMethod.EXCLUSIVE,
                 (TransformParameterSpec) null)),
             null, null));

        // create reference 2
        List<String> prefixList = new ArrayList<String>(2);
        prefixList.add("bar");
        prefixList.add("#default");
        ExcC14NParameterSpec params = new ExcC14NParameterSpec(prefixList);
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList
                (fac.newTransform(CanonicalizationMethod.EXCLUSIVE, params)),
             null, null));

        // create reference 3
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform
                (CanonicalizationMethod.EXCLUSIVE_WITH_COMMENTS,
                 (TransformParameterSpec) null)),
             null, null));

        // create reference 4
        prefixList = new ArrayList<String>(2);
        prefixList.add("bar");
        prefixList.add("#default");
        params = new ExcC14NParameterSpec(prefixList);
        refs.add(fac.newReference
            ("#xpointer(id('to-be-signed'))",
             fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform
                (CanonicalizationMethod.EXCLUSIVE_WITH_COMMENTS, params)),
             null, null));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(
            fac.newCanonicalizationMethod
                (CanonicalizationMethod.EXCLUSIVE,
                 (C14NMethodParameterSpec) null),
            fac.newSignatureMethod(SignatureMethod.DSA_SHA1, null), refs);

        // create KeyInfo
        List<XMLStructure> kits = new ArrayList<XMLStructure>(2);
        kits.add(kifac.newKeyValue(validatingKey));
        KeyInfo ki = kifac.newKeyInfo(kits);

        // create Objects
        Document doc = db.newDocument();
        Element baz = doc.createElementNS("urn:bar", "bar:Baz");
        Comment com = doc.createComment(" comment ");
        baz.appendChild(com);
        XMLObject obj = fac.newXMLObject(Collections.singletonList
            (new DOMStructure(baz)), "to-be-signed", null, null);

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature
            (si, ki, Collections.singletonList(obj), null, null);

        Element foo = doc.createElementNS("urn:foo", "Foo");
        foo.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns", "urn:foo");
        foo.setAttributeNS
            ("http://www.w3.org/2000/xmlns/", "xmlns:bar", "urn:bar");
        doc.appendChild(foo);

        DOMSignContext dsc = new DOMSignContext(signingKey, foo);
        dsc.putNamespacePrefix(XMLSignature.XMLNS, "dsig");

        sig.sign(dsc);

//      dumpDocument(doc, new FileWriter("/tmp/foo.xml"));

        DOMValidateContext dvc = new DOMValidateContext
            (new KeySelectors.KeyValueKeySelector(), foo.getLastChild());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }
        System.out.println();
    }
 

static void test_create_signature_reference_dependency() throws Exception {
        System.out.println("* Generating signature-reference-dependency.xml");
        // create references
        List<Reference> refs = Collections.singletonList
            (fac.newReference("#object-1", sha1));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(withoutComments, rsaSha1, refs);

        // create objects
        List<XMLStructure> objs = new ArrayList<XMLStructure>();

        // Object 1
        List<Reference> manRefs = Collections.singletonList
            (fac.newReference("#object-2", sha1));
        objs.add(fac.newXMLObject(Collections.singletonList
            (fac.newManifest(manRefs, "manifest-1")), "object-1", null, null));

        // Object 2
        Document doc = db.newDocument();
        Element nc = doc.createElementNS(null, "NonCommentandus");
        nc.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns", "");
        nc.appendChild(doc.createComment(" Commentandum "));
        objs.add(fac.newXMLObject(Collections.singletonList
            (new DOMStructure(nc)), "object-2", null, null));

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature(si, rsa, objs, "signature", null);
        DOMSignContext dsc = new DOMSignContext(getPrivateKey("RSA"), doc);

        sig.sign(dsc);

//      dumpDocument(doc, new PrintWriter(System.out));

        DOMValidateContext dvc = new DOMValidateContext
            (kvks, doc.getDocumentElement());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }

        System.out.println();
    }
 

static void test_create_sign_spec() throws Exception {
        System.out.println("* Generating sign-spec.xml");
        List<Reference> refs = new ArrayList<Reference>(2);

        // create reference 1
        List<XPathType> types = new ArrayList<XPathType>(3);
        types.add(new XPathType(" //ToBeSigned ", XPathType.Filter.INTERSECT));
        types.add(new XPathType(" //NotToBeSigned ",
            XPathType.Filter.SUBTRACT));
        types.add(new XPathType(" //ReallyToBeSigned ",
            XPathType.Filter.UNION));
        XPathFilter2ParameterSpec xp1 = new XPathFilter2ParameterSpec(types);
        refs.add(fac.newReference
            ("", fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform(Transform.XPATH2, xp1)),
             null, null));

        // create reference 2
        List<Transform> trans2 = new ArrayList<Transform>(2);
        trans2.add(fac.newTransform(Transform.ENVELOPED,
            (TransformParameterSpec) null));
        XPathFilter2ParameterSpec xp2 = new XPathFilter2ParameterSpec
            (Collections.singletonList
                (new XPathType(" / ", XPathType.Filter.UNION)));
        trans2.add(fac.newTransform(Transform.XPATH2, xp2));
        refs.add(fac.newReference("#signature-value",
            fac.newDigestMethod(DigestMethod.SHA1, null), trans2, null, null));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(
            fac.newCanonicalizationMethod
                (CanonicalizationMethod.INCLUSIVE,
                 (C14NMethodParameterSpec) null),
            fac.newSignatureMethod(SignatureMethod.DSA_SHA1, null), refs);

        // create KeyInfo
        List<XMLStructure> kits = new ArrayList<XMLStructure>(2);
        kits.add(kifac.newKeyValue(validatingKey));
        List<Object> xds = new ArrayList<Object>(2);
        xds.add("CN=User");
        xds.add(signingCert);
        kits.add(kifac.newX509Data(xds));
        KeyInfo ki = kifac.newKeyInfo(kits);

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature
            (si, ki, null, null, "signature-value");

        Document doc = db.newDocument();
        Element tbs1 = doc.createElementNS(null, "ToBeSigned");
        Comment tbs1Com = doc.createComment(" comment ");
        Element tbs1Data = doc.createElementNS(null, "Data");
        Element tbs1ntbs = doc.createElementNS(null, "NotToBeSigned");
        Element tbs1rtbs = doc.createElementNS(null, "ReallyToBeSigned");
        Comment tbs1rtbsCom = doc.createComment(" comment ");
        Element tbs1rtbsData = doc.createElementNS(null, "Data");
        tbs1rtbs.appendChild(tbs1rtbsCom);
        tbs1rtbs.appendChild(tbs1rtbsData);
        tbs1ntbs.appendChild(tbs1rtbs);
        tbs1.appendChild(tbs1Com);
        tbs1.appendChild(tbs1Data);
        tbs1.appendChild(tbs1ntbs);

        Element tbs2 = doc.createElementNS(null, "ToBeSigned");
        Element tbs2Data = doc.createElementNS(null, "Data");
        Element tbs2ntbs = doc.createElementNS(null, "NotToBeSigned");
        Element tbs2ntbsData = doc.createElementNS(null, "Data");
        tbs2ntbs.appendChild(tbs2ntbsData);
        tbs2.appendChild(tbs2Data);
        tbs2.appendChild(tbs2ntbs);

        Element document = doc.createElementNS(null, "Document");
        document.appendChild(tbs1);
        document.appendChild(tbs2);
        doc.appendChild(document);

        DOMSignContext dsc = new DOMSignContext(signingKey, document);

        sig.sign(dsc);

//      dumpDocument(doc, new FileWriter("/tmp/foo.xml"));

        DOMValidateContext dvc = new DOMValidateContext
            (new KeySelectors.KeyValueKeySelector(), document.getLastChild());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }
        System.out.println();
    }
 

static void test_create_sign_spec() throws Exception {
        System.out.println("* Generating sign-spec.xml");
        List<Reference> refs = new ArrayList<Reference>(2);

        // create reference 1
        List<XPathType> types = new ArrayList<XPathType>(3);
        types.add(new XPathType(" //ToBeSigned ", XPathType.Filter.INTERSECT));
        types.add(new XPathType(" //NotToBeSigned ",
            XPathType.Filter.SUBTRACT));
        types.add(new XPathType(" //ReallyToBeSigned ",
            XPathType.Filter.UNION));
        XPathFilter2ParameterSpec xp1 = new XPathFilter2ParameterSpec(types);
        refs.add(fac.newReference
            ("", fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform(Transform.XPATH2, xp1)),
             null, null));

        // create reference 2
        List<Transform> trans2 = new ArrayList<Transform>(2);
        trans2.add(fac.newTransform(Transform.ENVELOPED,
            (TransformParameterSpec) null));
        XPathFilter2ParameterSpec xp2 = new XPathFilter2ParameterSpec
            (Collections.singletonList
                (new XPathType(" / ", XPathType.Filter.UNION)));
        trans2.add(fac.newTransform(Transform.XPATH2, xp2));
        refs.add(fac.newReference("#signature-value",
            fac.newDigestMethod(DigestMethod.SHA1, null), trans2, null, null));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(
            fac.newCanonicalizationMethod
                (CanonicalizationMethod.INCLUSIVE,
                 (C14NMethodParameterSpec) null),
            fac.newSignatureMethod(SignatureMethod.DSA_SHA1, null), refs);

        // create KeyInfo
        List<XMLStructure> kits = new ArrayList<XMLStructure>(2);
        kits.add(kifac.newKeyValue(validatingKey));
        List<Object> xds = new ArrayList<Object>(2);
        xds.add("CN=User");
        xds.add(signingCert);
        kits.add(kifac.newX509Data(xds));
        KeyInfo ki = kifac.newKeyInfo(kits);

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature
            (si, ki, null, null, "signature-value");

        Document doc = db.newDocument();
        Element tbs1 = doc.createElementNS(null, "ToBeSigned");
        Comment tbs1Com = doc.createComment(" comment ");
        Element tbs1Data = doc.createElementNS(null, "Data");
        Element tbs1ntbs = doc.createElementNS(null, "NotToBeSigned");
        Element tbs1rtbs = doc.createElementNS(null, "ReallyToBeSigned");
        Comment tbs1rtbsCom = doc.createComment(" comment ");
        Element tbs1rtbsData = doc.createElementNS(null, "Data");
        tbs1rtbs.appendChild(tbs1rtbsCom);
        tbs1rtbs.appendChild(tbs1rtbsData);
        tbs1ntbs.appendChild(tbs1rtbs);
        tbs1.appendChild(tbs1Com);
        tbs1.appendChild(tbs1Data);
        tbs1.appendChild(tbs1ntbs);

        Element tbs2 = doc.createElementNS(null, "ToBeSigned");
        Element tbs2Data = doc.createElementNS(null, "Data");
        Element tbs2ntbs = doc.createElementNS(null, "NotToBeSigned");
        Element tbs2ntbsData = doc.createElementNS(null, "Data");
        tbs2ntbs.appendChild(tbs2ntbsData);
        tbs2.appendChild(tbs2Data);
        tbs2.appendChild(tbs2ntbs);

        Element document = doc.createElementNS(null, "Document");
        document.appendChild(tbs1);
        document.appendChild(tbs2);
        doc.appendChild(document);

        DOMSignContext dsc = new DOMSignContext(signingKey, document);

        sig.sign(dsc);

//      dumpDocument(doc, new FileWriter("/tmp/foo.xml"));

        DOMValidateContext dvc = new DOMValidateContext
            (new KeySelectors.KeyValueKeySelector(), document.getLastChild());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }
        System.out.println();
    }
 

static void test_create_signature_reference_dependency() throws Exception {
        System.out.println("* Generating signature-reference-dependency.xml");
        // create references
        List<Reference> refs = Collections.singletonList
            (fac.newReference("#object-1", sha1));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(withoutComments, rsaSha1, refs);

        // create objects
        List<XMLStructure> objs = new ArrayList<XMLStructure>();

        // Object 1
        List<Reference> manRefs = Collections.singletonList
            (fac.newReference("#object-2", sha1));
        objs.add(fac.newXMLObject(Collections.singletonList
            (fac.newManifest(manRefs, "manifest-1")), "object-1", null, null));

        // Object 2
        Document doc = db.newDocument();
        Element nc = doc.createElementNS(null, "NonCommentandus");
        nc.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns", "");
        nc.appendChild(doc.createComment(" Commentandum "));
        objs.add(fac.newXMLObject(Collections.singletonList
            (new DOMStructure(nc)), "object-2", null, null));

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature(si, rsa, objs, "signature", null);
        DOMSignContext dsc = new DOMSignContext(getPrivateKey("RSA", 512), doc);

        sig.sign(dsc);

//      dumpDocument(doc, new PrintWriter(System.out));

        DOMValidateContext dvc = new DOMValidateContext
            (kvks, doc.getDocumentElement());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }

        System.out.println();
    }
 

static void test_create_signature_reference_dependency() throws Exception {
        System.out.println("* Generating signature-reference-dependency.xml");
        // create references
        List<Reference> refs = Collections.singletonList
            (fac.newReference("#object-1", sha1));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(withoutComments, rsaSha1, refs);

        // create objects
        List<XMLStructure> objs = new ArrayList<XMLStructure>();

        // Object 1
        List<Reference> manRefs = Collections.singletonList
            (fac.newReference("#object-2", sha1));
        objs.add(fac.newXMLObject(Collections.singletonList
            (fac.newManifest(manRefs, "manifest-1")), "object-1", null, null));

        // Object 2
        Document doc = db.newDocument();
        Element nc = doc.createElementNS(null, "NonCommentandus");
        nc.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns", "");
        nc.appendChild(doc.createComment(" Commentandum "));
        objs.add(fac.newXMLObject(Collections.singletonList
            (new DOMStructure(nc)), "object-2", null, null));

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature(si, rsa, objs, "signature", null);
        DOMSignContext dsc = new DOMSignContext(getPrivateKey("RSA", 512), doc);

        sig.sign(dsc);

//      dumpDocument(doc, new PrintWriter(System.out));

        DOMValidateContext dvc = new DOMValidateContext
            (kvks, doc.getDocumentElement());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }

        System.out.println();
    }
 

static void test_create_sign_spec() throws Exception {
        System.out.println("* Generating sign-spec.xml");
        List<Reference> refs = new ArrayList<Reference>(2);

        // create reference 1
        List<XPathType> types = new ArrayList<XPathType>(3);
        types.add(new XPathType(" //ToBeSigned ", XPathType.Filter.INTERSECT));
        types.add(new XPathType(" //NotToBeSigned ",
            XPathType.Filter.SUBTRACT));
        types.add(new XPathType(" //ReallyToBeSigned ",
            XPathType.Filter.UNION));
        XPathFilter2ParameterSpec xp1 = new XPathFilter2ParameterSpec(types);
        refs.add(fac.newReference
            ("", fac.newDigestMethod(DigestMethod.SHA1, null),
             Collections.singletonList(fac.newTransform(Transform.XPATH2, xp1)),
             null, null));

        // create reference 2
        List<Transform> trans2 = new ArrayList<Transform>(2);
        trans2.add(fac.newTransform(Transform.ENVELOPED,
            (TransformParameterSpec) null));
        XPathFilter2ParameterSpec xp2 = new XPathFilter2ParameterSpec
            (Collections.singletonList
                (new XPathType(" / ", XPathType.Filter.UNION)));
        trans2.add(fac.newTransform(Transform.XPATH2, xp2));
        refs.add(fac.newReference("#signature-value",
            fac.newDigestMethod(DigestMethod.SHA1, null), trans2, null, null));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(
            fac.newCanonicalizationMethod
                (CanonicalizationMethod.INCLUSIVE,
                 (C14NMethodParameterSpec) null),
            fac.newSignatureMethod(SignatureMethod.DSA_SHA1, null), refs);

        // create KeyInfo
        List<XMLStructure> kits = new ArrayList<XMLStructure>(2);
        kits.add(kifac.newKeyValue(validatingKey));
        List<Object> xds = new ArrayList<Object>(2);
        xds.add("CN=User");
        xds.add(signingCert);
        kits.add(kifac.newX509Data(xds));
        KeyInfo ki = kifac.newKeyInfo(kits);

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature
            (si, ki, null, null, "signature-value");

        Document doc = db.newDocument();
        Element tbs1 = doc.createElementNS(null, "ToBeSigned");
        Comment tbs1Com = doc.createComment(" comment ");
        Element tbs1Data = doc.createElementNS(null, "Data");
        Element tbs1ntbs = doc.createElementNS(null, "NotToBeSigned");
        Element tbs1rtbs = doc.createElementNS(null, "ReallyToBeSigned");
        Comment tbs1rtbsCom = doc.createComment(" comment ");
        Element tbs1rtbsData = doc.createElementNS(null, "Data");
        tbs1rtbs.appendChild(tbs1rtbsCom);
        tbs1rtbs.appendChild(tbs1rtbsData);
        tbs1ntbs.appendChild(tbs1rtbs);
        tbs1.appendChild(tbs1Com);
        tbs1.appendChild(tbs1Data);
        tbs1.appendChild(tbs1ntbs);

        Element tbs2 = doc.createElementNS(null, "ToBeSigned");
        Element tbs2Data = doc.createElementNS(null, "Data");
        Element tbs2ntbs = doc.createElementNS(null, "NotToBeSigned");
        Element tbs2ntbsData = doc.createElementNS(null, "Data");
        tbs2ntbs.appendChild(tbs2ntbsData);
        tbs2.appendChild(tbs2Data);
        tbs2.appendChild(tbs2ntbs);

        Element document = doc.createElementNS(null, "Document");
        document.appendChild(tbs1);
        document.appendChild(tbs2);
        doc.appendChild(document);

        DOMSignContext dsc = new DOMSignContext(signingKey, document);

        sig.sign(dsc);

//      dumpDocument(doc, new FileWriter("/tmp/foo.xml"));

        DOMValidateContext dvc = new DOMValidateContext
            (new KeySelectors.KeyValueKeySelector(), document.getLastChild());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }
        System.out.println();
    }
 

static void test_create_signature_reference_dependency() throws Exception {
        System.out.println("* Generating signature-reference-dependency.xml");
        // create references
        List<Reference> refs = Collections.singletonList
            (fac.newReference("#object-1", sha1));

        // create SignedInfo
        SignedInfo si = fac.newSignedInfo(withoutComments, rsaSha1, refs);

        // create objects
        List<XMLStructure> objs = new ArrayList<XMLStructure>();

        // Object 1
        List<Reference> manRefs = Collections.singletonList
            (fac.newReference("#object-2", sha1));
        objs.add(fac.newXMLObject(Collections.singletonList
            (fac.newManifest(manRefs, "manifest-1")), "object-1", null, null));

        // Object 2
        Document doc = db.newDocument();
        Element nc = doc.createElementNS(null, "NonCommentandus");
        nc.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns", "");
        nc.appendChild(doc.createComment(" Commentandum "));
        objs.add(fac.newXMLObject(Collections.singletonList
            (new DOMStructure(nc)), "object-2", null, null));

        // create XMLSignature
        XMLSignature sig = fac.newXMLSignature(si, rsa, objs, "signature", null);
        DOMSignContext dsc = new DOMSignContext(getPrivateKey("RSA", 512), doc);

        sig.sign(dsc);

//      dumpDocument(doc, new PrintWriter(System.out));

        DOMValidateContext dvc = new DOMValidateContext
            (kvks, doc.getDocumentElement());
        XMLSignature sig2 = fac.unmarshalXMLSignature(dvc);

        if (sig.equals(sig2) == false) {
            throw new Exception
                ("Unmarshalled signature is not equal to generated signature");
        }
        if (sig2.validate(dvc) == false) {
            throw new Exception("Validation of generated signature failed");
        }

        System.out.println();
    }
 

/**
 * Creates an <code>XSLTTransformParameterSpec</code> with the specified
 * stylesheet.
 *
 * @param stylesheet the XSLT stylesheet to be used
 * @throws NullPointerException if <code>stylesheet</code> is
 *    <code>null</code>
 */
public XSLTTransformParameterSpec(XMLStructure stylesheet) {
    if (stylesheet == null) {
        throw new NullPointerException();
    }
    this.stylesheet = stylesheet;
}
 

/**
 * Creates an <code>XSLTTransformParameterSpec</code> with the specified
 * stylesheet.
 *
 * @param stylesheet the XSLT stylesheet to be used
 * @throws NullPointerException if <code>stylesheet</code> is
 *    <code>null</code>
 */
public XSLTTransformParameterSpec(XMLStructure stylesheet) {
    if (stylesheet == null) {
        throw new NullPointerException();
    }
    this.stylesheet = stylesheet;
}
 

/**
 * Creates an <code>XSLTTransformParameterSpec</code> with the specified
 * stylesheet.
 *
 * @param stylesheet the XSLT stylesheet to be used
 * @throws NullPointerException if <code>stylesheet</code> is
 *    <code>null</code>
 */
public XSLTTransformParameterSpec(XMLStructure stylesheet) {
    if (stylesheet == null) {
        throw new NullPointerException();
    }
    this.stylesheet = stylesheet;
}
 

/**
 * Creates an <code>XSLTTransformParameterSpec</code> with the specified
 * stylesheet.
 *
 * @param stylesheet the XSLT stylesheet to be used
 * @throws NullPointerException if <code>stylesheet</code> is
 *    <code>null</code>
 */
public XSLTTransformParameterSpec(XMLStructure stylesheet) {
    if (stylesheet == null) {
        throw new NullPointerException();
    }
    this.stylesheet = stylesheet;
}
 

/**
 * Creates an <code>XSLTTransformParameterSpec</code> with the specified
 * stylesheet.
 *
 * @param stylesheet the XSLT stylesheet to be used
 * @throws NullPointerException if <code>stylesheet</code> is
 *    <code>null</code>
 */
public XSLTTransformParameterSpec(XMLStructure stylesheet) {
    if (stylesheet == null) {
        throw new NullPointerException();
    }
    this.stylesheet = stylesheet;
}
 

/**
 * Creates an <code>XSLTTransformParameterSpec</code> with the specified
 * stylesheet.
 *
 * @param stylesheet the XSLT stylesheet to be used
 * @throws NullPointerException if <code>stylesheet</code> is
 *    <code>null</code>
 */
public XSLTTransformParameterSpec(XMLStructure stylesheet) {
    if (stylesheet == null) {
        throw new NullPointerException();
    }
    this.stylesheet = stylesheet;
}
 

/**
 * Creates a <code>CanonicalizationMethod</code> for the specified
 * algorithm URI and parameters. The parameters are specified as a
 * mechanism-specific <code>XMLStructure</code> (ex: {@link DOMStructure}).
 * This method is useful when the parameters are in XML form or there is
 * no standard class for specifying the parameters.
 *
 * @param algorithm the URI identifying the canonicalization algorithm
 * @param params a mechanism-specific XML structure from which to
 *   unmarshal the parameters from (may be <code>null</code> if
 *   not required or optional)
 * @return the <code>CanonicalizationMethod</code>
 * @throws ClassCastException if the type of <code>params</code> is
 *   inappropriate for this <code>XMLSignatureFactory</code>
 * @throws InvalidAlgorithmParameterException if the specified parameters
 *    are inappropriate for the requested algorithm
 * @throws NoSuchAlgorithmException if an implementation of the
 *    specified algorithm cannot be found
 * @throws NullPointerException if <code>algorithm</code> is
 *    <code>null</code>
 */
public abstract CanonicalizationMethod newCanonicalizationMethod(
    String algorithm, XMLStructure params)
    throws NoSuchAlgorithmException, InvalidAlgorithmParameterException;
 

/**
 * Marshals the algorithm-specific parameters. If there are no parameters
 * to be marshalled, this method returns without throwing an exception.
 *
 * @param parent a mechanism-specific structure containing the parent
 *    node that the marshalled parameters should be appended to
 * @param context the <code>XMLCryptoContext</code> containing
 *    additional context (may be <code>null</code> if not applicable)
 * @throws ClassCastException if the type of <code>parent</code> or
 *    <code>context</code> is not compatible with this
 *    <code>TransformService</code>
 * @throws NullPointerException if <code>parent</code> is <code>null</code>
 * @throws MarshalException if the parameters cannot be marshalled
 */
public abstract void marshalParams
    (XMLStructure parent, XMLCryptoContext context)
    throws MarshalException;
 

/**
 * Initializes this <code>TransformService</code> with the specified
 * parameters and document context.
 *
 * @param parent a mechanism-specific structure containing the parent
 *    structure
 * @param context the <code>XMLCryptoContext</code> containing
 *    additional context (may be <code>null</code> if not applicable)
 * @throws ClassCastException if the type of <code>parent</code> or
 *    <code>context</code> is not compatible with this
 *    <code>TransformService</code>
 * @throws NullPointerException if <code>parent</code> is <code>null</code>
 * @throws InvalidAlgorithmParameterException if the specified parameters
 *   are invalid for this algorithm
 */
public abstract void init(XMLStructure parent, XMLCryptoContext context)
    throws InvalidAlgorithmParameterException;
 

/**
 * Creates a <code>CanonicalizationMethod</code> for the specified
 * algorithm URI and parameters. The parameters are specified as a
 * mechanism-specific <code>XMLStructure</code> (ex: {@link DOMStructure}).
 * This method is useful when the parameters are in XML form or there is
 * no standard class for specifying the parameters.
 *
 * @param algorithm the URI identifying the canonicalization algorithm
 * @param params a mechanism-specific XML structure from which to
 *   unmarshal the parameters from (may be <code>null</code> if
 *   not required or optional)
 * @return the <code>CanonicalizationMethod</code>
 * @throws ClassCastException if the type of <code>params</code> is
 *   inappropriate for this <code>XMLSignatureFactory</code>
 * @throws InvalidAlgorithmParameterException if the specified parameters
 *    are inappropriate for the requested algorithm
 * @throws NoSuchAlgorithmException if an implementation of the
 *    specified algorithm cannot be found
 * @throws NullPointerException if <code>algorithm</code> is
 *    <code>null</code>
 */
public abstract CanonicalizationMethod newCanonicalizationMethod(
    String algorithm, XMLStructure params)
    throws NoSuchAlgorithmException, InvalidAlgorithmParameterException;
 

/**
 * Marshals the key info to XML.
 *
 * @param parent a mechanism-specific structure containing the parent node
 *    that the marshalled key info will be appended to
 * @param context the <code>XMLCryptoContext</code> containing additional
 *    context (may be null if not applicable)
 * @throws ClassCastException if the type of <code>parent</code> or
 *    <code>context</code> is not compatible with this key info
 * @throws MarshalException if the key info cannot be marshalled
 * @throws NullPointerException if <code>parent</code> is <code>null</code>
 */
void marshal(XMLStructure parent, XMLCryptoContext context)
    throws MarshalException;
 

/**
 * Unmarshals a new <code>KeyInfo</code> instance from a
 * mechanism-specific <code>XMLStructure</code> (ex: {@link DOMStructure})
 * instance.
 *
 * @param xmlStructure a mechanism-specific XML structure from which to
 *   unmarshal the keyinfo from
 * @return the <code>KeyInfo</code>
 * @throws NullPointerException if <code>xmlStructure</code> is
 *   <code>null</code>
 * @throws ClassCastException if the type of <code>xmlStructure</code> is
 *   inappropriate for this factory
 * @throws MarshalException if an unrecoverable exception occurs during
 *   unmarshalling
 */
public abstract KeyInfo unmarshalKeyInfo(XMLStructure xmlStructure)
    throws MarshalException;
 

/**
 * Unmarshals a new <code>XMLSignature</code> instance from a
 * mechanism-specific <code>XMLStructure</code> instance.
 * This method is useful if you only want to unmarshal (and not
 * validate) an <code>XMLSignature</code>.
 *
 * @param xmlStructure a mechanism-specific XML structure from which to
 *    unmarshal the signature from
 * @return the <code>XMLSignature</code>
 * @throws NullPointerException if <code>xmlStructure</code> is
 *    <code>null</code>
 * @throws ClassCastException if the type of <code>xmlStructure</code> is
 *    inappropriate for this factory
 * @throws MarshalException if an unrecoverable exception occurs
 *    during unmarshalling
 */
public abstract XMLSignature unmarshalXMLSignature
    (XMLStructure xmlStructure) throws MarshalException;
 

/**
 * Marshals the algorithm-specific parameters. If there are no parameters
 * to be marshalled, this method returns without throwing an exception.
 *
 * @param parent a mechanism-specific structure containing the parent
 *    node that the marshalled parameters should be appended to
 * @param context the <code>XMLCryptoContext</code> containing
 *    additional context (may be <code>null</code> if not applicable)
 * @throws ClassCastException if the type of <code>parent</code> or
 *    <code>context</code> is not compatible with this
 *    <code>TransformService</code>
 * @throws NullPointerException if <code>parent</code> is <code>null</code>
 * @throws MarshalException if the parameters cannot be marshalled
 */
public abstract void marshalParams
    (XMLStructure parent, XMLCryptoContext context)
    throws MarshalException;
 

/**
 * Creates a <code>SignatureProperty</code> containing the specified
 * list of {@link XMLStructure}s, target URI and optional id.
 *
 * @param content a list of one or more <code>XMLStructure</code>s. The list
 *    is defensively copied to protect against subsequent modification.
 * @param target the target URI of the Signature that this property applies
 *    to
 * @param id the id (may be <code>null</code>)
 * @return a <code>SignatureProperty</code>
 * @throws NullPointerException if <code>content</code> or
 *    <code>target</code> is <code>null</code>
 * @throws IllegalArgumentException if <code>content</code> is empty
 * @throws ClassCastException if <code>content</code> contains any
 *    entries that are not of type {@link XMLStructure}
 */
public abstract SignatureProperty newSignatureProperty
    (List<? extends XMLStructure> content, String target, String id);
 

/**
 * Creates a <code>CanonicalizationMethod</code> for the specified
 * algorithm URI and parameters. The parameters are specified as a
 * mechanism-specific <code>XMLStructure</code> (ex: {@link DOMStructure}).
 * This method is useful when the parameters are in XML form or there is
 * no standard class for specifying the parameters.
 *
 * @param algorithm the URI identifying the canonicalization algorithm
 * @param params a mechanism-specific XML structure from which to
 *   unmarshal the parameters from (may be <code>null</code> if
 *   not required or optional)
 * @return the <code>CanonicalizationMethod</code>
 * @throws ClassCastException if the type of <code>params</code> is
 *   inappropriate for this <code>XMLSignatureFactory</code>
 * @throws InvalidAlgorithmParameterException if the specified parameters
 *    are inappropriate for the requested algorithm
 * @throws NoSuchAlgorithmException if an implementation of the
 *    specified algorithm cannot be found
 * @throws NullPointerException if <code>algorithm</code> is
 *    <code>null</code>
 */
public abstract CanonicalizationMethod newCanonicalizationMethod(
    String algorithm, XMLStructure params)
    throws NoSuchAlgorithmException, InvalidAlgorithmParameterException;