src/org/apache/xml/security/keys/content/keyvalues/DSAKeyValue.java

/*
 * Copyright  1999-2004 The Apache Software Foundation.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.xml.security.keys.content.keyvalues;



import java.math.BigInteger;
import java.security.Key;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PublicKey;
import java.security.interfaces.DSAPublicKey;
import java.security.spec.DSAPublicKeySpec;
import java.security.spec.InvalidKeySpecException;

import org.apache.xml.security.exceptions.XMLSecurityException;
import org.apache.xml.security.utils.Constants;
import org.apache.xml.security.utils.I18n;
import org.apache.xml.security.utils.SignatureElementProxy;
import org.apache.xml.security.utils.XMLUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Element;


/**
 *
 * @author $Author$
 */
public class DSAKeyValue extends SignatureElementProxy
        implements KeyValueContent {

   /** {@link org.apache.commons.logging} logging facility */
    static org.apache.commons.logging.Log log = 
        org.apache.commons.logging.LogFactory.getLog(DSAKeyValue.class.getName());

   /**
    * Constructor DSAKeyValue
    *
    * @param element
    * @param BaseURI
    * @throws XMLSecurityException
    */
   public DSAKeyValue(Element element, String BaseURI)
           throws XMLSecurityException {
      super(element, BaseURI);
   }

   /**
    * Constructor DSAKeyValue
    *
    * @param doc
    * @param P
    * @param Q
    * @param G
    * @param Y
    */
   public DSAKeyValue(Document doc, BigInteger P, BigInteger Q, BigInteger G,
                      BigInteger Y) {

      super(doc);

      XMLUtils.addReturnToElement(this._constructionElement);
      this.addBigIntegerElement(P, Constants._TAG_P);
      this.addBigIntegerElement(Q, Constants._TAG_Q);
      this.addBigIntegerElement(G, Constants._TAG_G);
      this.addBigIntegerElement(Y, Constants._TAG_Y);
   }

   /**
    * Constructor DSAKeyValue
    *
    * @param doc
    * @param key
    * @throws IllegalArgumentException
    */
   public DSAKeyValue(Document doc, Key key) throws IllegalArgumentException {

      super(doc);

      XMLUtils.addReturnToElement(this._constructionElement);

      if (key instanceof java.security.interfaces.DSAPublicKey) {
         this.addBigIntegerElement(((DSAPublicKey) key).getParams().getP(),
                                   Constants._TAG_P);
         this.addBigIntegerElement(((DSAPublicKey) key).getParams().getQ(),
                                   Constants._TAG_Q);
         this.addBigIntegerElement(((DSAPublicKey) key).getParams().getG(),
                                   Constants._TAG_G);
         this.addBigIntegerElement(((DSAPublicKey) key).getY(),
                                   Constants._TAG_Y);
      } else {
         Object exArgs[] = { Constants._TAG_DSAKEYVALUE,
                             key.getClass().getName() };

         throw new IllegalArgumentException(I18n
            .translate("KeyValue.IllegalArgument", exArgs));
      }
   }

   /** @inheritDoc */
   public PublicKey getPublicKey() throws XMLSecurityException {

      try {
         DSAPublicKeySpec pkspec =
            new DSAPublicKeySpec(this
               .getBigIntegerFromChildElement(Constants._TAG_Y, Constants
               .SignatureSpecNS), this
                  .getBigIntegerFromChildElement(Constants._TAG_P, Constants
                  .SignatureSpecNS), this
                     .getBigIntegerFromChildElement(Constants._TAG_Q, Constants
                     .SignatureSpecNS), this
                        .getBigIntegerFromChildElement(Constants
                           ._TAG_G, Constants.SignatureSpecNS));
         KeyFactory dsaFactory = KeyFactory.getInstance("DSA");
         PublicKey pk = dsaFactory.generatePublic(pkspec);

         return pk;
      } catch (NoSuchAlgorithmException ex) {
         throw new XMLSecurityException("empty", ex);
      } catch (InvalidKeySpecException ex) {
         throw new XMLSecurityException("empty", ex);
      }
   }

   /** @inheritDoc */
   public String getBaseLocalName() {
      return Constants._TAG_DSAKEYVALUE;
   }
}