How to add namespace while signing XML file using javax.xml.crypto.dsig.*?

Question

I'm trying to sign an xml file using enveloped signature and javax.xml.crypto.dsig.* classes. As a result I get file with correct Signature content but with no namespace defined. How can I add xmlns:ds="http://www.w3.org/2000/09/xmldsig#" namespace and corresponding ds prefixes? I don't see any place where I could define it. Example code: ``` XMLSignatureFactory xmlSignatureFactory = XMLSignatureFactory.getInstance("DOM"); (...) XMLSignature signature = xmlSignatureFactory.newXMLSignature(signedInfo, keyInfo); // Marshal, generate, and sign the enveloped signature. signature.sign(domSignContext); ``` gives example XML: ```

Accepted Answer

Below is the sample code from Oracle for generating enveloped signature. And i guess what you are looking for is dsc.setDefaultNamespacePrefix("dsig"); as shown in the example below.

```
    XMLSignatureFactory fac = XMLSignatureFactory.getInstance("DOM");

Reference ref = fac.newReference
    ("", fac.newDigestMethod(DigestMethod.SHA1, null),
            Collections.singletonList
            (fac.newTransform
                    (Transform.ENVELOPED, (TransformParameterSpec) null)),
                    null, null);

// Create the SignedInfo
    SignedInfo si = fac.newSignedInfo
    (fac.newCanonicalizationMethod
            (CanonicalizationMethod.INCLUSIVE_WITH_COMMENTS,
                    (C14NMethodParameterSpec) null),
                    fac.newSignatureMethod(SignatureMethod.DSA_SHA1, null),
                    Collections.singletonList(ref));

// Create a DSA KeyPair
    KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA");
    kpg.initialize(512);
    KeyPair kp = kpg.generateKeyPair();

// Create a KeyValue containing the DSA PublicKey that was generated
    KeyInfoFactory kif = fac.getKeyInfoFactory();
    KeyValue kv = kif.newKeyValue(kp.getPublic());

// Create a KeyInfo and add the KeyValue to it
    KeyInfo ki = kif.newKeyInfo(Collections.singletonList(kv));

// Instantiate the document to be signed
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setNamespaceAware(true);
    Document doc =  dbf.newDocumentBuilder().parse(new FileInputStream(sourceFile));

// Create a DOMSignContext and specify the DSA PrivateKey and
    // location of the resulting XMLSignature's parent element
    DOMSignContext dsc = new DOMSignContext(kp.getPrivate(), doc.getDocumentElement());
    dsc.setDefaultNamespacePrefix("dsig");

// Create the XMLSignature (but don't sign it yet)
    XMLSignature signature = fac.newXMLSignature(si, ki);

// Marshal, generate (and sign) the enveloped signature
    signature.sign(dsc);

// output the resulting document
    OutputStream os;
    os = new FileOutputStream(DestinationFile);

TransformerFactory tf = TransformerFactory.newInstance();
    Transformer trans = tf.newTransformer();
    trans.transform(new DOMSource(doc), new StreamResult(os));
```

How to add namespace while signing XML file using javax.xml.crypto.dsig.*?

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