I need help - I can help - Prevent Acrobat Reader from linearizing while save

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Prevent Acrobat Reader from linearizing while save

Printed From: Debenu Quick PDF Library - PDF SDK Community Forum
Category: For Users of the Library
Forum Name: I need help - I can help
Forum Description: Problems and solutions while programming with the Debenu Quick PDF Library and Debenu PDF Viewer SDK
URL: http://www.quickpdf.org/forum/forum_posts.asp?TID=1778
Printed Date: 25 Jan 26 at 12:23PM
Software Version: Web Wiz Forums 11.01 - http://www.webwizforums.com

Topic: Prevent Acrobat Reader from linearizing while save

Posted By: kukulkan
Subject: Prevent Acrobat Reader from linearizing while save
Date Posted: 22 Mar 11 at 10:15AM

Hi,

The Acrobat Reader seems to manipulate (linearize) PDF documents while saving. I need to keep the exact structure of the document even if the user saves the document (without changing anything). Acrobat Reader does not linearize, if the document is signed (that is good). But of several reasons, I can not sign the document.

Is there another secure way to prevent Acrobat Reader from linearizion? Any flag or information to add?

Thank you,

Kukulkan

Replies:

Posted By: Ingo
Date Posted: 22 Mar 11 at 10:24AM

Hi!

I think using a main password
should solve the problem?

Cheers, Ingo

Posted By: kukulkan
Date Posted: 22 Mar 11 at 10:50AM

Hi Ingo,

Thank you for your quick reply.

The problem is, that we like to send many document to employees and others. In many cases, we do not have any additional contact. Upon this, we can not provide a password for everyone of them. Not even, if it was always the same. Or did I misunderstood something?

The Acrobat Reader seems to be the only PDF reader who wants to linearize the documents. Neither Foxit nor SumatraPDF etc. are doing like that.

Is there any other way to prevent Acrobat Reader from such? Removing the "CanChange" permission is not working to prevent from linearizion.

Kukulkan

Posted By: kukulkan
Date Posted: 22 Mar 11 at 11:11AM

Ok, I found out what you mean. Set only a password against manipulation. This works good, as Acrobat Reader does not try to linearize this documents anymore.

The problem is, that we get normal (unencrypted) PDF. After adding a small additional information, we need to set this password (or flag). But this seems to manipulate the objects that are already included. This is not allowed for us (as they are already hashed using SHA256). This would destroy our integrity information (we do not use the PDF functions for that).

Are there any other values that we can set to prevent linearizion? How is a PDF marked as PDF/A? Would such a mark prevent linearizion?

Kukulkan