java - encryption exception with PDFBox while the file is readable -

i using pdfbox extracting text pdf file in java. works fine in of cases have problem pdf files follows:

exception in thread "main" java.io.ioexception: javax.crypto.illegalblocksizeexception: input length must multiple of 16 when decrypting padded cipher 

the files have following properties

is there way can open type of files extract contents?

i guess getting error because try extract texts page page. , page extraction here not allowed! but, picture suggests content copying allowed. also, can open file , see content! then, there should way opening , getting content of these files. right?

this link example of pdf file have problem.

the exception occured @ following line if objnr = 9

securityhandler.decryptstream(stream, objnr, objgennr); 

then, if set program proceed line if objnr != 9 works fine! know why happens? have pdf file work when objnr != 10. idea?

the code have (tested latest version of pdfbox try , see if problem because of version use) follows

import java.io.ioexception;  public class test {     public static void main(string[] args) throws ioexception {         pdfmanager pdfmanager = new pdfmanager();         pdfmanager.setfilepath("pathtothepdffile");         system.out.println(pdfmanager.totext());     } }   import org.apache.pdfbox.pdfparser.pdfparser; import org.apache.pdfbox.pdmodel.pddocument; import org.apache.pdfbox.util.pdftextstripper; import org.apache.pdfbox.cos.cosdocument; import java.io.file; import java.io.fileinputstream; import java.io.ioexception;   public class pdfmanager {     private pdfparser parser;     private pdftextstripper pdfstripper;     private pddocument pddoc ;     private cosdocument cosdoc ;      private string text ;     private string filepath;     private file file;      public pdfmanager() {      }     public string totext() throws ioexception     {         this.pdfstripper = null;         this.pddoc = null;         this.cosdoc = null;          file = new file(filepath);         parser = new pdfparser(new fileinputstream(file));          parser.parse();         cosdoc = parser.getdocument();         pdfstripper = new pdftextstripper();         pddoc = new pddocument(cosdoc);         pddoc.getnumberofpages();         pdfstripper.setstartpage(1);         pdfstripper.setendpage(10);         text = pdfstripper.gettext(pddoc);         return text;     }      public void setfilepath(string filepath) {          this.filepath = filepath;     } }