I need help - I can help - Locking created pdf

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Locking created pdf

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=746
Printed Date: 17 May 24 at 1:04PM
Software Version: Web Wiz Forums 11.01 - http://www.webwizforums.com

Topic: Locking created pdf

Posted By: perry
Subject: Locking created pdf
Date Posted: 18 Jun 07 at 2:16PM

Does anyone know of any way to 'lock' the created pdf so that it cannot be updated by quickpdf, acrobat or any other software. I have a feeling that there is something in Acrobat SDK but can't find anything in iSed QiickPdf

Replies:

Posted By: bogey
Date Posted: 18 Jun 07 at 2:36PM

This is how I do it in VBScript:

function secureForm(thisDoc)
call QP.SelectDocument(thisDoc)
 fncDebug(" Securing Form")
 '===========================================
 'Set Document Information
 '===========================================
 'QP.SetInformation(0) = "" 'PDF Version
 call QP.SetInformation(1,"Union Central") 'Author
 call QP.SetInformation(2,"") 'Title
 call QP.SetInformation(3,"") 'Subject
 call QP.SetInformation(4,"") 'KeyWords
 call QP.SetInformation(5,"Union Central") 'Creator
 call QP.SetInformation(6,Request.ServerVariables("SERVER_NAME")) 'Producer

'===========================================
 'Lock each PDF file prior to delivery
 '===========================================
 'Default Permissions
 permissions = "10011011"
 'for 40 bit encryption
 '1.canPrint (ALLOW Printing )
 '2.canCopy (ALLOW content copying or extraction, content accessibility enabled)
 '3.canChange (ALLOW Changing the document, Form Fill-in & signing, Document Assembly)
 '4.canAddNotes (ALLOW Authoring Comments and Form Fields, Form Field Fill-in & Signing)
 'for 128 bit encryption (not used, only compatible with Acrobat 5 and up)
 '5.canFillFields YES,
 '6.canCopyAccess NO,
 '7.canAssemble YES,
 '8.canPrintFull YES
 fncDebug(" Setting Form Permissions = " & permissions)
 'Permissions - canPrint, canCopy, canChange, canAddNotes, canFillFields, canCopyAccess, canAssemble, canPrintFull
 permissions=QP.Permissions(returnbln(permissions,1), returnbln(permissions,2), returnbln(permissions,3), returnbln(permissions,4), returnbln(permissions,5), returnbln(permissions,6), returnbln(permissions,7), returnbln(permissions,8))

'encrypt 40 bit for compatibility with acrobat 3 and 4
call QP.Encrypt(PDFPassword,"",0,permissions)
secureForm = QP.SelectedDocument
end function

Posted By: perry
Date Posted: 28 Jun 07 at 4:18AM

Hi Bogey

thanks for this excellent example.

Having disabled 'change,copy' etc, does this enable me to distribute the document so that they can view it without knowing any password but prevent them from editing it with any PDF software?

thanks.

Posted By: Ingo
Date Posted: 28 Jun 07 at 4:35AM

Hi Perry!

Yes. Using only the main password protects your settings but the reader doesn't need a password to read the document.
If the user shall insert a password before reading you have to set the user password, too.

Keep in mind that there are tools out there for removing the main password from pdf-documents... It's not really safe. A user password is much safer ... but uncomfortable for the readers.

Best regards,
Ingo

Posted By: marian_pascalau
Date Posted: 28 Jun 07 at 5:01AM

Perry,

a short info. Please keep in mind that only few applications will protect data inside PDF files. If user is able to open your document he is able to modify whatever he wants.

There is no real way to protect your document for changes. The only possibility is to protect it with password and a digital certificate. Any user will be able to alter your document but will break for sure the signature of your original file.

Best regards, Marian

Posted By: bogey
Date Posted: 28 Jun 07 at 8:15AM

Locking a PDF with a password does nothing more than keep the honest people honest. It is far too easy to crack for someone that is determined.