OpenSAML user discussion

["Giuseppe Sarno" <>]

Hi I receive this exception trying to sign a simple Request message:

org.opensaml.xml.io.MarshallingException: Unable to construct signature Element {http://www.w3.org/2000/09/xmldsig#}Sign
ature
        at org.opensaml.xml.signature.SignatureMarshaller.createSignatureElement(SignatureMarshaller.java:146)
        at org.opensaml.xml.signature.SignatureMarshaller.marshall(SignatureMarshaller.java:69)
        at org.opensaml.xml.io.AbstractXMLObjectMarshaller.marshallChildElements(AbstractXMLObjectMarshaller.java:371)
        at org.opensaml.xml.io.AbstractXMLObjectMarshaller.marshallInto(AbstractXMLObjectMarshaller.java:262)
        at org.opensaml.xml.io.AbstractXMLObjectMarshaller.marshall(AbstractXMLObjectMarshaller.java:152)
        at org.opensaml.xml.io.AbstractXMLObjectMarshaller.marshall(AbstractXMLObjectMarshaller.java:96)
       .................................

Caused by: org.apache.xml.security.signature.XMLSignatureException: The requested algorithm null does not exist. Origina
l Message was: null
Original Exception was java.lang.NullPointerException
        at org.apache.xml.security.algorithms.SignatureAlgorithm.<init>(Unknown Source)
        at org.apache.xml.security.signature.SignedInfo.<init>(Unknown Source)
        at org.apache.xml.security.signature.XMLSignature.<init>(Unknown Source)
        at org.apache.xml.security.signature.XMLSignature.<init>(Unknown Source)
        at org.opensaml.xml.signature.SignatureMarshaller.createSignatureElement(SignatureMarshaller.java:107)
        ... 10 more

 

I followed the instructions on the WiKi this is the code ...

 

public static SignableSAMLObject   signObject (SignableSAMLObject obj)
    {

       SAMLObjectContentReference  ref = new SAMLObjectContentReference(obj);
        SignatureBuilder build = new SignatureBuilder();
       
        Signature sign = build.buildObject();
        sign.getContentReferences().add(ref);
        PublicKey pubKey = null;
        PrivateKey privKey = null;
        try
        {
            KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA");
           keyGen.initialize(1024);
           KeyPair keypair = keyGen.genKeyPair();
           pubKey = keypair.getPublic();
           privKey = keypair.getPrivate();
        }
        catch (NoSuchAlgorithmException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
       
        sign.setSigningKey(privKey);
        obj.setSignature(sign);
       
        return obj;

 

 

Then I Marshal the Object with this function and here I get the Exception:

 

public static  Element marshalSAMLMsg(XMLObject saml_obj)
    {
        MarshallerFactory marshallerFactory = Configuration.getMarshallerFactory();
        System.out.println("BLAH"); 
        if (saml_obj == null){
            System.out.println("OBJ");
        }
        else
            if (marshallerFactory == null)
            {
                System.out.println("FACTORY"); 
            }
            else{
                System.out.println("NONE");
            }
       
        // Get the Subject marshaller
        Marshaller marshaller = marshallerFactory.getMarshaller(saml_obj);

 

        // Marshall the Subject
        Element element = null;
      try {
              element = marshaller.marshall(saml_obj);
      } catch (MarshallingException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
      }
        return element;
}

 

Any idea ?

 

thanks.