Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free, no registration required.

I've found lots of info on decrypting PDF files, but none on encrypting them. What tool can do this for me?

Edit: There are two good answers below, but in my specific case the PDF was a scan, not a document that I'd created.

share|improve this question
1  
Related questions on Stack Overflow and Super User. –  Martin Schröder Feb 21 '13 at 21:56

5 Answers 5

up vote 21 down vote accepted

Use pdftk. From its man page:

Encrypt a PDF using 128-Bit Strength (the Default) and Withhold All Permissions (the Default)

$ pdftk [mydoc].pdf output [mydoc.128].pdf owner_pw [foopass]

Same as Above, Except a Password is Required to Open the PDF

$ pdftk [mydoc].pdf output [mydoc.128].pdf owner_pw [foo] user_pw [baz]

Same as Above, Except Printing is Allowed (after the PDF is Open)

$ pdftk [mydoc].pdf output [mydoc.128].pdf owner_pw [foo] user_pw [baz] allow printing

pdftk has a lot of other uses as well and is worth installing if one works extensively with PDF files. To quote from the write-up in Synaptic:

If PDF is electronic paper, then pdftk is an electronic stapler-remover, hole-punch, binder, secret-decoder-ring, and X-Ray-glasses. Pdftk is a simple tool for doing everyday things with PDF documents. Keep one in the top drawer of your desktop and use it to:

  • Merge PDF documents
  • Split PDF pages into a new document
  • Decrypt input as necessary (password required)
  • Encrypt output as desired
  • Fill PDF Forms with FDF Data and/or Flatten Forms
  • Apply a Background Watermark
  • Report PDF on metrics, including metadata and bookmarks
  • Update PDF Metadata
  • Attach Files to PDF Pages or the PDF Document
  • Unpack PDF Attachments
  • Burst a PDF document into single pages
  • Uncompress and re-compress page streams
  • Repair corrupted PDF (where possible)
share|improve this answer
    
Worked perfectly, thanks. –  mfisch Feb 20 '13 at 17:49
2  
If you wish a GUI for pdftk, you can try pdfchain that works good. For the above needing, you can use the Concatenate tab, adding only one PDF, and settings permissions options and password. –  Pisu Feb 26 '13 at 22:27
1  
The most recent release of pdfchain brings a number of enhancements but isn't available from the official repositories yet. You can install it via this PPA (maintained by the developers): launchpad.net/~pdfchain-team/+archive/ppa –  Glutanimate Feb 27 '13 at 10:33
    
I tried the first example with pdftk 1.44, and I could open the resulting PDF without a password using evince. Only after adding user_pw was the document actually protected. –  Joey Adams Aug 8 '13 at 20:43

If you use LibreOffice and export a document as PDF (Menu > File > Export as PDF), there's the option to set a password:

enter image description here

share|improve this answer
    
Unfortunately my PDF is from a scan, but that would be a good general solution. –  mfisch Feb 20 '13 at 17:30
2  
Shouldn't it still be possible since you can import images into LibreOffice and then export as PDF? –  user25656 Feb 20 '13 at 17:36

qpdf can encrypt and decrypt pdfs. And linearize them, too.

share|improve this answer

One possible solution is to use jpdf Tweak.

share|improve this answer

PDF Chain is an awesome tool for this. It is a GUI for pdftk

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.