unlock protected pdf files

Question

I need to process a large number of protected pdf files and edit them using a java program, but i don't have the passwords for these files. Is there any way to unlock this files with a batch?

I would like a windows command like tool or a java open source api. What is the best solution ?

Answer 1

are these pdf files asking for passwords to be opened, or protection consist in restrictions about copy, printing, modify, text extraction and so on?

if this is your case, you can try with

qpdf

• http://qpdf.sourceforge.net/

usage:

qpdf --decrypt file.pdf unlocked.pdf

and can be used in a batch operation en masse, in this way

for f in *.pdf ; do qpdf --decrypt $f ${f%%.pdf}unlocked.pdf; done

Answer 2

For decryption, you can use PDFBox, see my answer here : https://stackoverflow.com/a/9976481/535203

I give a sample code to decrypt a PDF given its password.

There is also a binary to do that with PDFBox, check the usage here.

Answer 3

You can also do it using iText library.

Here is a sample code :

        PdfReader.unethicalreading = true;
        PdfReader reader = new PdfReader(inputFile);
        PdfEncryptor.encrypt(reader, new FileOutputStream(outputFile), null,
              null, PdfWriter.ALLOW_ASSEMBLY | PdfWriter.ALLOW_COPY
                  | PdfWriter.ALLOW_DEGRADED_PRINTING | PdfWriter.ALLOW_FILL_IN
                  | PdfWriter.ALLOW_MODIFY_ANNOTATIONS | PdfWriter.ALLOW_MODIFY_CONTENTS
                  | PdfWriter.ALLOW_PRINTING | PdfWriter.ALLOW_SCREENREADERS, false);

P.S. : use unethicalreading flag on your own risk.