/**

  * Copyright 2005-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.ksb.security.service.impl;

 import java.io.IOException;

 import java.security.GeneralSecurityException;

 import java.security.KeyException;

 import java.security.PublicKey;

 import java.security.Signature;

 import java.security.cert.Certificate;

 import java.security.cert.CertificateException;

 import org.kuali.rice.core.api.resourceloader.GlobalResourceLoader;

 import org.kuali.rice.ksb.security.admin.service.JavaSecurityManagementService;

 import org.kuali.rice.ksb.security.service.DigitalSignatureService;

 import org.kuali.rice.ksb.util.KSBConstants;

 public class DigitalSignatureServiceImpl implements DigitalSignatureService {

         public Signature getSignatureForSigning() throws IOException, GeneralSecurityException {

                 Signature signature = getSignature();

                 signature.initSign(getJavaSecurityManagementService().getModulePrivateKey());

                 return signature;

         }

     public Signature getSignatureForVerification(String verificationAlias) throws IOException, GeneralSecurityException {

         Certificate cert = getJavaSecurityManagementService().getCertificate(verificationAlias);

         return getSignatureForVerification(cert);

     }

     public Signature getSignatureForVerification(Certificate certificate) throws IOException, GeneralSecurityException {

         if (certificate == null) {

             throw new CertificateException("Could not find certificate");

         }

         PublicKey publicKey = certificate.getPublicKey();

         if (publicKey == null) {

             throw new KeyException("Could not find the public key from valid certificate");

         }

         Signature signature = getSignature();

         signature.initVerify(publicKey);

         return signature;

     }

         protected Signature getSignature() throws GeneralSecurityException {

                 return Signature.getInstance(getJavaSecurityManagementService().getModuleSignatureAlgorithm());

         }

         protected JavaSecurityManagementService getJavaSecurityManagementService() {

                 return (JavaSecurityManagementService)GlobalResourceLoader.getService(KSBConstants.ServiceNames.JAVA_SECURITY_MANAGEMENT_SERVICE);

         }

 }