LinuxQuestions.org
Share your knowledge at the LQ Wiki.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Software
User Name
Password
Linux - Software This forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.

Notices


Reply
  Search this Thread
Old 04-05-2015, 01:57 PM   #1
CVAlkan
Member
 
Registered: Nov 2012
Location: Northwest suburbs of Chicago
Distribution: Ubuntu & Mint LTS, Manjaro Rolling; Android
Posts: 242

Rep: Reputation: Disabled
Copy protect pdf files without password


Hi:

I am generating a pdf from LibreOffice, and the only way one can protect the output pdf from being printed or changed requires that a password be set on the document, which I don't wish to do.

I have the popler library installed, as well as most of the available GUI programs for controlling it (pdfSAM, pdfChain, pdfMod, and pdfShuffler), but can't seem to figure out how to do this.

Am I missing something obvious, or is this just not possible?

Thanks for any pointers.
 
Old 04-06-2015, 07:51 AM   #2
rtmistler
Moderator
 
Registered: Mar 2011
Location: USA
Distribution: MINT Debian, Angstrom, SUSE, Ubuntu, Debian
Posts: 9,882
Blog Entries: 13

Rep: Reputation: 4930Reputation: 4930Reputation: 4930Reputation: 4930Reputation: 4930Reputation: 4930Reputation: 4930Reputation: 4930Reputation: 4930Reputation: 4930Reputation: 4930
Someone can correct me if I'm mistaken but I do not believe you can protect something from being printed, after all someone can capture screenshots and print those.

I'm also not sure that even if you password protect it that this will do it. Why? Many years ago one of our Marketing guys came to me to ask how he could capture text from a PDF file, because it was password protected and the company which had created it was no longer around. Whether this was allowable or not is a different question, but we found a pdf2text Linux utility which was provided in source. We tried it and found that the password stopped us. Then someone said, "Well we got the code, just find the point where it validates the password and make that always be success." That worked and we basically made a pdf2text utility which didn't require passwords.

A better protection would be that someone couldn't view it without a passphrase. But you're saying you do not wish to use any passwords. Just not sure you can attain any level of protection without a password.
 
Old 04-06-2015, 08:50 AM   #3
273
LQ Addict
 
Registered: Dec 2011
Location: UK
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680

Rep: Reputation: 2373Reputation: 2373Reputation: 2373Reputation: 2373Reputation: 2373Reputation: 2373Reputation: 2373Reputation: 2373Reputation: 2373Reputation: 2373Reputation: 2373
To follow on from above: The only way to prevent information from being accessed is to use encryption and encryption requires keys. So, you need a shared secret to protect any information pretty much by definition. If you're not going to use a password then what will you use as the key?
 
Old 04-06-2015, 09:09 AM   #4
CVAlkan
Member
 
Registered: Nov 2012
Location: Northwest suburbs of Chicago
Distribution: Ubuntu & Mint LTS, Manjaro Rolling; Android
Posts: 242

Original Poster
Rep: Reputation: Disabled
All good replies, but there are certain considerations worth mentioning:

The pdf is over 400 pages, so the idea of someone using screen shots to print several pages is not really an issue ("fair use" and all that sort of thing). If someone wants to attempt printing out the entire book I would be honored to believe they think that's worth while doing, but it would be more time and cost-effective to simply purchase the print version.

The intent is not really to prevent access to the information, but to prevent wide distribution with no recompense or, even worse, someone else buying one copy and then reselling it themselves.

But thanks for the thoughts...
 
Old 04-07-2015, 06:55 PM   #5
jefro
Moderator
 
Registered: Mar 2008
Posts: 21,976

Rep: Reputation: 3623Reputation: 3623Reputation: 3623Reputation: 3623Reputation: 3623Reputation: 3623Reputation: 3623Reputation: 3623Reputation: 3623Reputation: 3623Reputation: 3623
Most of those pdf security deals can be bypassed. I had an app that could do it. It protects only from honest people.

There really is no 100% way to protect a file that one can read or view.

I'd just put the restrictions on the file and leave it. The other protection if you could call it that would be to copyright it.

Last edited by jefro; 04-08-2015 at 02:51 PM.
 
Old 04-07-2015, 11:26 PM   #6
veerain
Senior Member
 
Registered: Mar 2005
Location: Earth bound to Helios
Distribution: Custom
Posts: 2,524

Rep: Reputation: 319Reputation: 319Reputation: 319Reputation: 319
Or you have to implement some custom DRM code.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
How do you password protect a .pdf? cheeseandpenguins General 8 05-07-2015 06:50 AM
Is there a way to remove password protect from pdf bee505r Linux - Software 5 08-01-2011 01:39 PM
LXer: Protect Your PostScript Files from Being Converted to PDF LXer Syndicated Linux News 0 05-14-2009 07:12 PM
How do I password protect folders/files? shodekiagari Linux - Software 6 12-04-2004 12:16 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Software

All times are GMT -5. The time now is 12:37 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration