source: fedd/abac-src/ttg/credential/SignCredential.java @ df783c1

package com.nailabs.abac.credential;

import java.security.*;
import java.security.cert.*;
import org.w3c.dom.*;
import org.apache.xml.security.signature.*;
import org.apache.xml.security.exceptions.*;
import org.apache.xml.security.transforms.Transforms;
import org.apache.xml.security.utils.*;

/**
 * A utility for signing a credential domain document.
 */
public class SignCredential extends Application {
    /** signature algorithm is set to DSA */
    protected static String SIG_TYPE = XMLSignature.ALGO_ID_SIGNATURE_DSA;
    /** digest algorithm is SHA-1 */
    protected static String DIGEST_TYPE = Constants.ALGO_ID_DIGEST_SHA1;

    protected static String KEY_PAIR_TYPE = "DSA";

    protected PrivateKey privateKey = null;

    protected PublicKey publicKey = null;
    
    protected X509Certificate cert = null;

    /** 
     * Constructor for the application which reads in an XML document, 
     * parses the doc into a DOM tree, signs the document, and writes
     * the signed tree into an XML file. Cryptographic material is supplied
     * by a Java keystore.
     */
    public SignCredential(String argv[]) {
        super(argv);
        name = "SignCredential";
        parseParameters();
        getKeys();
        readDoc();
        signDoc();
        writeDoc();
    }

    private void generateKeyPair() {
        if(DEBUG) {
            out.println("Generating random keypair for use in signature");
            out.println("(useful for demo purposes only)" );
        }
        try {
            KeyPairGenerator kpg = KeyPairGenerator.getInstance(KEY_PAIR_TYPE);
            kpg.initialize(512);
            KeyPair newKeyPair = kpg.generateKeyPair();
            privateKey = newKeyPair.getPrivate();
            publicKey = newKeyPair.getPublic();
        } catch( java.security.NoSuchAlgorithmException nsae ) {
            if(DEBUG)nsae.printStackTrace();
        }
    }

    protected void getKeys() {
        super.getKeys();       // loads the keystore to a class instance field
        if( keys == null )
            generateKeyPair(); // Generate a random, one-time-use key
        else {
            try {
                cert = (X509Certificate)keyStore.getCertificate(alias);
                publicKey = cert.getPublicKey();
                privateKey = 
                    (PrivateKey)keyStore.getKey(alias, password.toCharArray());
            } catch( Exception e ) {
                cert = null;
                publicKey = null;
                e.printStackTrace();
            }
        }
    }

    protected void signDoc() {
        try {
            String baseURI = outXML.toURL().toString();
            XMLSignature sig = new XMLSignature(doc, baseURI, SIG_TYPE );
            docElement.appendChild( sig.getElement() );
            Transforms transforms = new Transforms( doc );
            transforms.addTransform(Transforms.TRANSFORM_ENVELOPED_SIGNATURE );
            transforms.addTransform( Transforms.TRANSFORM_C14N_WITH_COMMENTS );
            if( includeTransform ) {
                sig.addDocument("", transforms, DIGEST_TYPE);
            }
            if( includeCert && ( cert != null ) ) {
                sig.addKeyInfo( cert );
            } else if( publicKey != null )
                sig.addKeyInfo( publicKey );
            sig.sign( privateKey );
        } catch( XMLSecurityException xmlse ) {
            xmlse.printStackTrace();
        } catch( java.net.MalformedURLException murle ) {
            murle.printStackTrace();
        }
    }


    /** standard main routine for launching the application */
    public static void main(String argv[]) {
        SignCredential sc = new SignCredential(argv);
    }

}