java program to password protect a signed pdf file using itext pdfstamper

[pavithra murthy]

please could anyone help me out ...i have written this code for digitally signing pdf. here
when i compile the code works fine but after running and entering a user id i get an exception

D:\password>java EncryptPDF
USERNAME:PASSWORD
Please enter your username
shiva
pavithra: pvm4kor
shompa: sos5kor
shiva: snk3kor
passwordsnk3kor
hello
Exception in thread "main" java.io.IOException: Bad user password
at com.lowagie.text.pdf.PdfReader.readDecryptedDocObj(Unknown Source)
at com.lowagie.text.pdf.PdfReader.readDocObj(Unknown Source)
at com.lowagie.text.pdf.PdfReader.readPdf(Unknown Source)
at com.lowagie.text.pdf.PdfReader.<init>(Unknown Source)
at com.lowagie.text.pdf.PdfReader.<init>(Unknown Source)
at EncryptPDF.main(EncryptPDF.java:85)

import java.io.FileOutputStream;
import java.util.*;
import java.io.*;

import com.lowagie.text.pdf.PdfEncryptor;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfStamper;
import com.lowagie.text.pdf.PdfWriter;
import com.lowagie.text.Rectangle;
import com.lowagie.text.pdf.AcroFields;
import com.lowagie.text.pdf.PdfPKCS7;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfSignatureAppearance;
import com.lowagie.text.pdf.PdfStamper;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.Iterator;

public class EncryptPDF {
   
  public static void main(String[] args) throws Exception {
	String password="";String username="";
    
   
    
			  //....................
			  HashMap hm = new HashMap(); 
			  BufferedReader dataIn = new BufferedReader(new InputStreamReader( System.in) );

			  System.out.println("USERNAME"+":"+"PASSWORD");
			  hm .put("pavithra", "pvm4kor");
			  hm .put("shompa", "sos5kor");
			  hm .put("vinod", "vim2kor");
			  hm .put("shiva", "snk3kor");

			  // Get a set of the entries
			  Set set = hm.entrySet();
			  // Get an iterator
			  Iterator i = set.iterator();

			  //System.out.println("Please enter your protection password");
			  //   			password = dataIn.readLine();

			  System.out.println("Please enter your username");
			  username = dataIn.readLine();

			  // Display elements
			  String mName;
	  while(i.hasNext()) 
	  {
                               
			  Map.Entry me = (Map.Entry)i.next();
			  System.out.print(me.getKey() + ": ");
			  System.out.println(me.getValue());
									  
			  //cheks when username is entered with the password                         
			  if   (username.equals((String)me.getKey())) 
			  {
				  password= (String)me.getValue();
				  System.out.println("password"+password);
			  }
       
		  //code password protect pdf 
		  if (password.equals((String)me.getValue()))
		  {
			  System.out.println("hello");
			//  mName=(String)me.getValue();
			  PdfReader reader = new PdfReader("ch01.pdf");
			  PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("Encrypted1.pdf"));
			  //stamper.setEncryption("Hello".getBytes(), password.getBytes(), PdfWriter.AllowPrinting | PdfWriter.AllowCopy, PdfWriter.STRENGTH40BITS);
			    stamper.setEncryption(true,password, null, PdfWriter.AllowPrinting );
			  stamper.close();
		  //removed }
         
		  //digitally signing pdf
		  PdfReader reader1 = new PdfReader("Encrypted1.pdf");
		  int nomPage = reader1.getNumberOfPages();
		  System.out.println("nomPage: "+nomPage);

			  //vvvvvvvvvvvvvvvvvvvvvvvvvvvvdigitally signing code 
			  try
			  {
				  KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
				  ks.load(new FileInputStream("keystore.ks"), "my_password".toCharArray());
				  String alias = (String)ks.aliases().nextElement();
				  PrivateKey key = (PrivateKey)ks.getKey(alias, "my_password".toCharArray());
				  java.security.cert.Certificate[] chain = ks.getCertificateChain(alias);
				  //PdfReader reader = new PdfReader("ch01out.pdf");
      
				  for (int j=1; j<=nomPage; j++)
				  {

					  FileOutputStream fout = new FileOutputStream("signed"+j+".pdf");
					  //PdfStamper stp = PdfStamper.createSignature(reader, fout, '\0');
					  PdfStamper stp = PdfStamper.createSignature(reader1, fout, '\0', null, true);
					  //PdfStamper.setEncryption(chain,AllowDegradedPrinting,ENCRYPTION_AES);
					  PdfSignatureAppearance sap = stp.getSignatureAppearance();
					  sap.setCrypto(key, chain, null, PdfSignatureAppearance.WINCER_SIGNED);
					  sap.setReason("I'm the author");
					  sap.setLocation("Lisbon");
					  // comment next line to have an invisible signature
					  sap.setVisibleSignature(new Rectangle(100, 100, 200, 200), j, null);
					  stp.close();
					  reader1 = new PdfReader("signed"+j+".pdf");
				  }
				  for(int j=1;j<=nomPage;j++)
				  {
					  File fileStr = new File("signed"+j+".pdf");
					  if(j!=nomPage)
					  {
						  fileStr.delete();
					  }
					  //to verify sign
					  if(j == nomPage)
					  {
						  try 
						  {
							  CertificateFactory cf = CertificateFactory.getInstance("X509");
							  Collection col = cf.generateCertificates(new FileInputStream("export.cer"));
							  KeyStore kall = KeyStore.getInstance(KeyStore.getDefaultType());
							  kall.load(null, null);
							  for (Iterator it = col.iterator(); it.hasNext();) 
							  {
								  X509Certificate cert = (X509Certificate)it.next();
								  kall.setCertificateEntry(cert.getSerialNumber().toString(Character.MAX_RADIX), cert);
							  }
							  //KeyStore kall = PdfPKCS7.loadCacertsKeyStore();
							  PdfReader reader2 = new PdfReader("signed"+j+".pdf");
							  AcroFields af = reader2.getAcroFields();
							  ArrayList names = af.getSignatureNames();
							  for (int k = 0; k < names.size(); ++k) 
							  {
								  String name = (String)names.get(k);
								  System.out.println("Signature name: " + name);
								  System.out.println("Signature covers whole document: " + af.signatureCoversWholeDocument(name));
								  System.out.println("Document revision: " + af.getRevision(name) + " of " + af.getTotalRevisions());
							
								  PdfPKCS7 pk = af.verifySignature(name);
								  Calendar cal = pk.getSignDate();
								  java.security.cert.Certificate pkc[] = pk.getCertificates();
								  System.out.println("Subject: " + PdfPKCS7.getSubjectFields(pk.getSigningCertificate()));
								  System.out.println("Document modified: " + !pk.verify());
								  Object fails[] = PdfPKCS7.verifyCertificates(pkc, kall, null, cal);
								  if (fails == null)
									  System.out.println("Certificates verified against the KeyStore");
								  else
									  System.out.println("Certificate failed: " + fails[1]);
							  } //for k=0
						  } //try
						  catch(Exception e) {e.printStackTrace();}
					  }  //if(j == nomPage)

				  } // for(int j=1;j<=nomPage;j++)

			  }
			  catch(Exception e) {e.printStackTrace();}
	  } //if password correc

	  }//while
//.......................
  } //main close
}//encryptpdf close

thanks in advance ...

[Tim McGuire]

on line 85, I think you need to supply your user password:

  
PdfReader reader1 = new PdfReader("Encrypted1.pdf");  

according to the API, (http://1t3xt.info/api/com/lowagie/text/pdf/PdfReader.html) this should work:

PdfReader reader1 = new PdfReader("Encrypted1.pdf",password.getBytes());

[Rob Spoor]

Moving to Other Open Source Projects.

[pavithra murthy]

hello friend ,

i modified the program and put the password in PDFReader . but that exception is not going ..bad user password...but however i am getting the protected signed pdf ....but am getting signature in only one pdf..
please could you help me out ..

import java.io.FileOutputStream;
import java.util.*;
import java.io.*;

import com.lowagie.text.pdf.PdfEncryptor;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfStamper;
import com.lowagie.text.pdf.PdfWriter;
import com.lowagie.text.Rectangle;
import com.lowagie.text.pdf.AcroFields;
import com.lowagie.text.pdf.PdfPKCS7;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfSignatureAppearance;
import com.lowagie.text.pdf.PdfStamper;
import com.lowagie.text.pdf.*;


import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.Iterator;

public class EncryptPDF {
   
  public static void main(String[] args) throws Exception {

	  try
	  {

	String password="";String username="";
          
			  //....................
			  HashMap hm = new HashMap(); 
			  BufferedReader dataIn = new BufferedReader(new InputStreamReader(System.in) );

			  System.out.println("USERNAME"+":"+"PASSWORD");
			  hm .put("pavithra", "pvm4kor");
			  hm .put("shompa", "sos5kor");
			  hm .put("vinod", "vim2kor");
			  hm .put("shiva", "snk3kor");

			  // Get a set of the entries
			  Set set = hm.entrySet();
			  // Get an iterator
			  Iterator i = set.iterator();

			  System.out.println("Please enter your username");
			  username = dataIn.readLine();

			  // Display elements
			  String mName;
		  
			  while(i.hasNext()) 
			  {
                               
				  Map.Entry me = (Map.Entry)i.next();
				  System.out.print(me.getKey() + ": ");
				  System.out.println(me.getValue());
									  
				  //cheks when username is entered with the password                         
				  if   (username.equals((String)me.getKey())) 
				  {
					  password= (String)me.getValue();
					  System.out.println("password"+password);
				  }
       
				  //code password protect pdf 
				  if (password.equals((String)me.getValue()))
				  {
					  System.out.println("hello");
					  //  mName=(String)me.getValue();
					  PdfReader readerx = new PdfReader("d:\\password\\Password_Based_Encryption_20060501.pdf");
					  PdfStamper stamper = new PdfStamper(readerx, new FileOutputStream("Encrypted1.pdf"));
					  //stamper.setEncryption("Hello".getBytes(), password.getBytes(), PdfWriter.AllowPrinting | PdfWriter.AllowCopy, PdfWriter.STRENGTH40BITS);
					  stamper.setEncryption("Hello".getBytes(),password.getBytes(), PdfWriter.AllowPrinting| PdfWriter.AllowCopy, PdfWriter.STRENGTH40BITS );
					  stamper.close();
					  //removed }
				  }
			  }//while
		  		    //digitally signing pdf
		  PdfReader reader = new PdfReader("Encrypted1.pdf",password.getBytes());
		  int nomPage = reader.getNumberOfPages();
		  System.out.println("nomPage: "+nomPage);

			  //vvvvvvvvvvvvvvvvvvvvvvvvvvvvdigitally signing code 
			  try
			  {
				
				  KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
				  ks.load(new FileInputStream("d:\\keystore.ks"), "my_password".toCharArray());
				  String alias = (String)ks.aliases().nextElement();
				  PrivateKey key = (PrivateKey)ks.getKey(alias, "my_password".toCharArray());
				  java.security.cert.Certificate[] chain = ks.getCertificateChain(alias);
				  //PdfReader reader = new PdfReader("ch01out.pdf");
      
				  for (int j=1; j<=nomPage; j++)
				  {

					  FileOutputStream fout = new FileOutputStream("signed"+j+".pdf");
					  //PdfStamper stp = PdfStamper.createSignature(reader, fout, '\0');
					  PdfStamper stp = PdfStamper.createSignature(reader, fout, '\0', null, true);
					  //PdfStamper.setEncryption(chain,AllowDegradedPrinting,ENCRYPTION_AES);
					  PdfSignatureAppearance sap = stp.getSignatureAppearance();
					  sap.setCrypto(key, chain, null, PdfSignatureAppearance.WINCER_SIGNED);
					  sap.setReason("I'm the author");
					  sap.setLocation("Karnataka");
					  // comment next line to have an invisible signature
					  sap.setVisibleSignature(new Rectangle(100, 100, 200, 200), j, null);
					  stp.close();
					  reader = new PdfReader("signed"+j+".pdf");
				  }
				  for(int j=1;j<=nomPage;j++)
				  {
					  File fileStr = new File("signed"+j+".pdf");
					  if(j!=nomPage)
					  {
						  fileStr.delete();
					  }
					  //to verify sign
					  if(j == nomPage)
					  {
						  try 
						  {
							  CertificateFactory cf = CertificateFactory.getInstance("X509");
							  Collection col = cf.generateCertificates(new FileInputStream("d:\\export.cer"));
							  KeyStore kall = KeyStore.getInstance(KeyStore.getDefaultType());
							  kall.load(null, null);
							  for (Iterator it = col.iterator(); it.hasNext();) 
							  {
								  X509Certificate cert = (X509Certificate)it.next();
								  kall.setCertificateEntry(cert.getSerialNumber().toString(Character.MAX_RADIX), cert);
							  }
							  //KeyStore kall = PdfPKCS7.loadCacertsKeyStore();
							  PdfReader reader2 = new PdfReader("signed"+j+".pdf");
							  AcroFields af = reader2.getAcroFields();
							  ArrayList names = af.getSignatureNames();
							  for (int k = 0; k < names.size(); ++k) 
							  {
								  String name = (String)names.get(k);
								  System.out.println("Signature name: " + name);
								  System.out.println("Signature covers whole document: " + af.signatureCoversWholeDocument(name));
								  System.out.println("Document revision: " + af.getRevision(name) + " of " + af.getTotalRevisions());
							
								  PdfPKCS7 pk = af.verifySignature(name);
								  Calendar cal = pk.getSignDate();
								  java.security.cert.Certificate pkc[] = pk.getCertificates();
								  System.out.println("Subject: " + PdfPKCS7.getSubjectFields(pk.getSigningCertificate()));
								  System.out.println("Document modified: " + !pk.verify());
								  Object fails[] = PdfPKCS7.verifyCertificates(pkc, kall, null, cal);
								  if (fails == null)
									  System.out.println("Certificates verified against the KeyStore");
								  else
									  System.out.println("Certificate failed: " + fails[1]);
							  } //for k=0
						  } //try
						  catch(Exception e) {e.printStackTrace();}
					  }  //if(j == nomPage)

				  } // for(int j=1;j<=nomPage;j++)

			  }
			  catch(Exception e) {e.printStackTrace();}
	 // } //if password correc

	  //repplace while colose here
//.......................
	  } //try
	  catch(Exception e) {e.printStackTrace();}
  } //main close
}//encryptpdf close

[Tim McGuire]

pavithra murthy wrote:i modified the program and put the password in PDFReader . but that exception is not going ..bad user password...but however i am getting the protected signed pdf ....but am getting signature in only one pdf..
please could you help me out ..

Hi I'm not clear on which error you are seeing now. Could you post the error output?