Linux - SoftwareThis 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
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
Distribution: Ubuntu & Mint LTS, Manjaro Rolling; Android
Posts: 242
Rep:
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?
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.
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,672
Rep:
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?
Distribution: Ubuntu & Mint LTS, Manjaro Rolling; Android
Posts: 242
Original Poster
Rep:
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.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.