Java Tutorial/PDF/PDF Encrypt Decrypt

Decrypt Pdf file

   <source lang="java">

import java.io.FileOutputStream; import com.lowagie.text.pdf.PdfEncryptor; import com.lowagie.text.pdf.PdfReader; import com.lowagie.text.pdf.PdfStamper; import com.lowagie.text.pdf.PdfWriter; public class MainClass {

 public static void main(String[] args) throws Exception {
   PdfEncryptor
       .encrypt(new PdfReader("1.pdf"), new FileOutputStream("Encrypted2.pdf"),
           "Hello".getBytes(), "World".getBytes(), PdfWriter.AllowDegradedPrinting,
           PdfWriter.STRENGTH128BITS);
   // decrypt the file
   PdfReader reader = new PdfReader("Encrypted2.pdf", "World".getBytes());
   PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("Decrypted1.pdf"));
   stamper.close();
   getEncryptionInformation("1.pdf", null);
   getEncryptionInformation("Encrypted2.pdf", "World");
   getEncryptionInformation("Decrypted1.pdf", "World");
 }
 public static void getEncryptionInformation(String filename, String ownerpassword)
     throws Exception {
   PdfReader reader;
   if (ownerpassword == null)
     reader = new PdfReader(filename);
   else
     reader = new PdfReader(filename, ownerpassword.getBytes());
   System.out.println("Encrypted? " + reader.isEncrypted());
   if (reader.isEncrypted()) {
     System.out.println("Permissions: "
         + PdfEncryptor.getPermissionsVerbose(reader.getPermissions()));
     System.out.println("128 bit? " + reader.is128Key());
   }
 }

}</source>

Degraded printing

   <source lang="java">

import java.io.FileOutputStream; import com.lowagie.text.pdf.PdfEncryptor; import com.lowagie.text.pdf.PdfReader; import com.lowagie.text.pdf.PdfStamper; import com.lowagie.text.pdf.PdfWriter; public class MainClass {

 public static void main(String[] args) throws Exception {
   PdfEncryptor
       .encrypt(new PdfReader("1.pdf"), new FileOutputStream("Encrypted2.pdf"),
           "Hello".getBytes(), "World".getBytes(), PdfWriter.AllowDegradedPrinting,
           PdfWriter.STRENGTH128BITS);
   getEncryptionInformation("1.pdf", null);
   getEncryptionInformation("Encrypted2.pdf", "World");
 }
 public static void getEncryptionInformation(String filename, String ownerpassword)
     throws Exception {
   PdfReader reader;
   if (ownerpassword == null)
     reader = new PdfReader(filename);
   else
     reader = new PdfReader(filename, ownerpassword.getBytes());
   System.out.println("Encrypted? " + reader.isEncrypted());
   if (reader.isEncrypted()) {
     System.out.println("Permissions: "
         + PdfEncryptor.getPermissionsVerbose(reader.getPermissions()));
     System.out.println("128 bit? " + reader.is128Key());
   }
 }

}</source>

Encrypt the file with PdfStamper

   <source lang="java">

import java.io.FileOutputStream; import com.lowagie.text.pdf.PdfEncryptor; import com.lowagie.text.pdf.PdfReader; import com.lowagie.text.pdf.PdfStamper; import com.lowagie.text.pdf.PdfWriter; public class MainClass {

 public static void main(String[] args) throws Exception {
   PdfReader reader = new PdfReader("1.pdf");
   PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("Encrypted1.pdf"));
   stamper.setEncryption("Hello".getBytes(), "World".getBytes(), PdfWriter.AllowPrinting
       | PdfWriter.AllowCopy, PdfWriter.STRENGTH40BITS);
   stamper.close();
   getEncryptionInformation("1.pdf", null);
   getEncryptionInformation("Encrypted1.pdf", "World");
 }
 public static void getEncryptionInformation(String filename, String ownerpassword)
     throws Exception {
   PdfReader reader;
   if (ownerpassword == null)
     reader = new PdfReader(filename);
   else
     reader = new PdfReader(filename, ownerpassword.getBytes());
   System.out.println("Encrypted? " + reader.isEncrypted());
   if (reader.isEncrypted()) {
     System.out.println("Permissions: "
         + PdfEncryptor.getPermissionsVerbose(reader.getPermissions()));
     System.out.println("128 bit? " + reader.is128Key());
   }
 }

}</source>

Get Encryption Information

   <source lang="java">

import java.io.FileOutputStream; import com.lowagie.text.pdf.PdfEncryptor; import com.lowagie.text.pdf.PdfReader; import com.lowagie.text.pdf.PdfStamper; import com.lowagie.text.pdf.PdfWriter; public class MainClass {

 public static void main(String[] args) throws Exception {
   PdfReader reader = new PdfReader("1.pdf");
   PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("Encrypted1.pdf"));
   stamper.setEncryption("Hello".getBytes(), "World".getBytes(), PdfWriter.AllowPrinting
       | PdfWriter.AllowCopy, PdfWriter.STRENGTH40BITS);
   stamper.close();
   getEncryptionInformation("1.pdf", null);
   getEncryptionInformation("Encrypted1.pdf", "World");
 }
 public static void getEncryptionInformation(String filename, String ownerpassword)
     throws Exception {
   PdfReader reader;
   if (ownerpassword == null)
     reader = new PdfReader(filename);
   else
     reader = new PdfReader(filename, ownerpassword.getBytes());
   System.out.println("Encrypted? " + reader.isEncrypted());
   if (reader.isEncrypted()) {
     System.out.println("Permissions: "
         + PdfEncryptor.getPermissionsVerbose(reader.getPermissions()));
     System.out.println("128 bit? " + reader.is128Key());
   }
 }

}</source>