1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
   10    *
   11    * Unless required by applicable law or agreed to in writing, software
   12    * distributed under the License is distributed on an "AS IS" BASIS,
   13    * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   14    * See the License for the specific language governing permissions and
   15    * limitations under the License.
   16    */
   17   package org.apache.pdfbox.examples.signature;
   18   
   19   import java.io.ByteArrayInputStream;
   20   import java.io.IOException;
   21   
   22   import java.security.cert.CertificateFactory;
   23   
   24   import java.util.Collection;
   25   
   26   import org.apache.pdfbox.cos.COSArray;
   27   import org.apache.pdfbox.cos.COSDictionary;
   28   import org.apache.pdfbox.cos.COSName;
   29   import org.apache.pdfbox.cos.COSString;
   30   
   31   import org.apache.pdfbox.pdmodel.PDDocument;
   32   
   33   /**
   34    * This will read a document from the filesystem, decrypt it and do something with the signature.
   35    *
   36    * usage: java org.apache.pdfbox.examples.signature.ShowSignature <password> <inputfile>
   37    *
   38    *
   39    * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
   40    * @version $Revision: 1.9 $
   41    */
   42   public class ShowSignature
   43   {
   44   
   45       private ShowSignature()
   46       {
   47       }
   48       /**
   49        * This is the entry point for the application.
   50        *
   51        * @param args The command-line arguments.
   52        *
   53        * @throws Exception If there is an error reading the file.
   54        */
   55       public static void main( String[] args ) throws Exception
   56       {
   57           ShowSignature show = new ShowSignature();
   58           show.showSignature( args );
   59       }
   60   
   61       private void showSignature( String[] args ) throws Exception
   62       {
   63           if( args.length != 2 )
   64           {
   65               usage();
   66           }
   67           else
   68           {
   69               String password = args[0];
   70               String infile = args[1];
   71               PDDocument document = null;
   72               try
   73               {
   74                   document = PDDocument.load( infile );
   75   
   76                   if( document.isEncrypted() )
   77                   {
   78                       document.decrypt( password );
   79                   }
   80                   else
   81                   {
   82                       System.err.println( "Warning: Document is not encrypted." );
   83                   }
   84   
   85                   COSDictionary trailer = document.getDocument().getTrailer();
   86                   COSDictionary root = (COSDictionary)trailer.getDictionaryObject( COSName.ROOT );
   87                   COSDictionary acroForm = (COSDictionary)root.getDictionaryObject( COSName.ACRO_FORM );
   88                   COSArray fields = (COSArray)acroForm.getDictionaryObject( COSName.FIELDS );
   89                   for( int i=0; i<fields.size(); i++ )
   90                   {
   91                       COSDictionary field = (COSDictionary)fields.getObject( i );
   92                       String type = field.getNameAsString( "FT" );
   93                       if( "Sig".equals( type ) )
   94                       {
   95                           COSDictionary cert = (COSDictionary)field.getDictionaryObject( COSName.V );
   96                           if( cert != null )
   97                           {
   98                               System.out.println( "Certificate found" );
   99                               System.out.println( "Name=" + cert.getDictionaryObject( COSName.NAME ) );
  100                               System.out.println( "Modified=" + cert.getDictionaryObject( COSName.getPDFName( "M" ) ) );
  101                               COSName subFilter = (COSName)cert.getDictionaryObject( COSName.getPDFName( "SubFilter" ) );
  102                               if( subFilter != null )
  103                               {
  104                                   if( subFilter.getName().equals( "adbe.x509.rsa_sha1" ) )
  105                                   {
  106                                       COSString certString = (COSString)cert.getDictionaryObject(
  107                                           COSName.getPDFName( "Cert" ) );
  108                                       byte[] certData = certString.getBytes();
  109                                       CertificateFactory factory = CertificateFactory.getInstance( "X.509" );
  110                                       ByteArrayInputStream certStream = new ByteArrayInputStream( certData );
  111                                       Collection certs = factory.generateCertificates( certStream );
  112                                       System.out.println( "certs=" + certs );
  113                                   }
  114                                   else if( subFilter.getName().equals( "adbe.pkcs7.sha1" ) )
  115                                   {
  116                                       COSString certString = (COSString)cert.getDictionaryObject(
  117                                           COSName.CONTENTS );
  118                                       byte[] certData = certString.getBytes();
  119                                       CertificateFactory factory = CertificateFactory.getInstance( "X.509" );
  120                                       ByteArrayInputStream certStream = new ByteArrayInputStream( certData );
  121                                       Collection certs = factory.generateCertificates( certStream );
  122                                       System.out.println( "certs=" + certs );
  123                                   }
  124                                   else
  125                                   {
  126                                       System.err.println( "Unknown certificate type:" + subFilter );
  127                                   }
  128                               }
  129                               else
  130                               {
  131                                   throw new IOException( "Missing subfilter for cert dictionary" );
  132                               }
  133                           }
  134                           else
  135                           {
  136                               System.out.println( "Signature found, but no certificate" );
  137                           }
  138                       }
  139                   }
  140               }
  141               finally
  142               {
  143                   if( document != null )
  144                   {
  145                       document.close();
  146                   }
  147               }
  148           }
  149       }
  150   
  151       /**
  152        * This will print a usage message.
  153        */
  154       private static void usage()
  155       {
  156           System.err.println( "usage: java org.apache.pdfbox.examples.signature.ShowSignature " +
  157                               "<password> <inputfile>" );
  158       }
  159   
  160   }