Security problem

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adoucette
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Posts: 10
Joined: Sat May 10, 2014 12:54 am

Security problem

Post by adoucette »

How can I effectively protect a PDF?
I just used the Editor to password-protect a PDF and then it was VERY easy to unlock.
I have purchased PDF XChange Pro, and have just used the editor to set a 24-character random password on a PDF. The settings I used were Acrobat 9, 256-bit AES, and no printing, copying, etc. I have attached a screen capture of the password settings, see here:
2014-07-16_9-16-38.pdf
So the encrypted PDF is here:
Abraham Lincoln on failure and loss.pdf
But then I went to pdfunlock.com and it INSTANTLY unlocked the PDF. Attached here:
Abraham+Lincoln+on+failure+and+loss.unlocked.pdf
Is password security really this easy to crack? How can I effectively protect a PDF? Is there something I'm doing wrong? This is a substantial part of why I purchased a pro-version of the program.

Thanks,
Ari
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Stefan - PDF-XChange
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Re: Security problem

Post by Stefan - PDF-XChange »

Hello Ari,

Welcome to our forums.
If there is a password for opening the PDF it can not be removed or skipped, but if the document can be opened (even if it requires a password for opening but the password is known) then removing the permissions restrictions is indeed not too complicated. This is a limitation on the PDF specification unfortunately.

A possible solution is a third party security handler like e.g. FileOpen - both our Editor and Adobe's products support this third party tool, and with it you can guarantee that the security restrictions you've placed on a file will be observed. FileOpen is free to use to open already protected files, however I am not too sure what is the fee for using it to protect new files you will be asked to pay.

Regards,
Stefan
adoucette
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Posts: 10
Joined: Sat May 10, 2014 12:54 am

Re: Security problem

Post by adoucette »

Thanks Stefan. Unfortunately, FileOpen costs $3K per year...
What is the solution for a home/educational or SOHO user who just wants to secure a PDF so others can't copy/extract text from it?

Ari
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Stefan - PDF-XChange
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Joined: Mon Jan 12, 2009 8:07 am

Re: Security problem

Post by Stefan - PDF-XChange »

Hi Ari,

You can try to e.g. export the original file to images, then create a new PDF from the images. This way there will be no text to be copied, but someone could OCR that image and still get selectable text - so protecting your intellectual property once you've sent a file with it (in any form) is a tricky matter, and if someone is determined to copy it - there will be a way. Even if they need to have it open on one screen and manually type the same text in say a notepad :)

Regards,
Stefan
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Ivan - Tracker Software
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Re: Security problem

Post by Ivan - Tracker Software »

If you set BOTH user and owner passwords (i.e. 'Document open' and 'Change permissions' passwords), it would be much-much harder to unlock your PDF files.
When your know at least one of two passwords in password secured PDF file, you can get access to entire document, as the specified permissions are just declarative instructions for viewers.
PDF-XChange Co Ltd. (Project Director)

When attaching files to any message - please ensure they are archived and posted as a .ZIP, .RAR or .7z format - or they will not be posted - thanks.