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Hidden PDF protection?

Printed From: Foxit's Planet PDF Forum
Category: Lets Talk PDF
Forum Name: JavaScript
Forum Description: Discussions relating to the use of JavaScript within PDF.
Printed Date: 29 Feb 2020 at 12:36pm
Software Version: Web Wiz Forums 11.10 -

Topic: Hidden PDF protection?
Posted By: 20GT
Subject: Hidden PDF protection?
Date Posted: 20 Mar 2016 at 4:24pm
As some of you know there is no true way to lock a PDF from being edited. I want to make it hard for the buyer to remove their name from the Plantiff filed.

Since I cannot lock my PDF I want to make it hard to edit by locking/protective scripts hidden in the PDF itself. This lock could be partially configured (on/off) on the last page of the pdf that will be deleted just before selling so that I can edit if needed.

It does not have to be done this way but it has to obtain the desired effect.

Any suggestions?


My PDF needs document level scripts to work.

This code will also contain two trigger scripts. One to detect changes in afield another to detect added fields. It will look for changes to the Plaintiff field. If they can't change it, they will try to leave it but add another field to pull their new plaintiff value from, but this will trigger the second script because the number of fields has now changed.

I want to obfuscate those scripts in among 50 similar but long and drawn out document level inert scripts. Inert as in meaningless. These scripts will be named with lIlIlIlI copied in Ariel font so they appear as the same but are actually lIlIlIlI




Using /* something */ 25 lines long.

To add to the time consuming complexity. Also turning them into machine code so they actually have to copy/paste and decipher each page

This will mean that the thief will have to do more than just unlock it. They will also have to decipher and then search the java-script to remove the trigger code. Which your average lazy thief won't do.

Posted By: gkaiseril
Date Posted: 20 Mar 2016 at 7:06pm
Is not this approach counter to the reason the PDF format was first developed for?

If you want true protection have your client sign a trade secrets contract and strictly enforce it. This is how Coca Cola protects their secret recipe well as very strict access to the formula. But once the information is made public the signers to the contract cannot release their copy but they can direct others to the released documentation,.

You should seek legal advice about how to protect intellectual property. And be ready to defend your claim to ownership. Just having a patent or copyright is not absolute control, but a right to defend your claim.

Posted By: 20GT
Date Posted: 20 Mar 2016 at 10:28pm
Hi George I should have guessed you would be a Senior Member on this forum also. lolSmile

That would probably be the correct way of  protect intellectual property.  But Coca Cola is a billion dollar company and they have resources available to them that I don't, the primary one being cash. It takes money to go to court to fight for my rights. So being the cash strapped person that I am, I trying to implement a less expensive way to protect my PDF. 

Is not this approach counter to the reason the PDF format was first developed for?
I thought that the Portable Document Format (PDF) was created to present documents in a manner independent of application software, hardware, and operating systems.

Posted By: Rob Lyman
Date Posted: 22 Mar 2016 at 8:12pm
A better solution would be to add a signature field to the document, and use it to sign the document once the desired fields have been filled in. PDF signatures are designed to make it immediately evident that a form has been changed, in a way that is virtually impossible to obscure or refute. They can also, if necessary, withstand legal scrutiny.  They are defined in the official PDF specification, and well supported by Acrobat and other PDF tools.

The PDF format is an open standard, and there are many people knowledgeable enough to defeat a homegrown security scheme that has not been subject to rigorous mathematical analysis and vulnerability testing. The PDF signature mechanism is based on industry cryptography standards and is considered highly secure.

http:// - http://

Rob Lyman
Software Engineer

Posted By: 20GT
Date Posted: 24 Mar 2016 at 1:03am
not sure I understand.
pay the 120$ a year then when you send the PDF for signature what do they actually get? just a signature page? the entire PDF? what happens if they don't sign it ? do they have a working copy? what happens if the sign it with a fake name?

Posted By: 20GT
Date Posted: 24 Mar 2016 at 1:09am
Originally posted by Rob Lyman Rob Lyman wrote:

once the desired fields have been filled in

They have to fill in the document from their end. this is something they will do repeatedly at different times

If they have a copy to fill in, what's to stop them from just using it and never finishing the signature process 

Posted By: gkaiseril
Date Posted: 25 Mar 2016 at 4:47pm
Nothing. This is the same if they get a paper form from the county and do not complete and mail the form.

Posted By: gkaiseril
Date Posted: 25 Mar 2016 at 4:51pm
The get of completed form with a legally binding signature that should be honored in any court in the U.S.

Note that the site used to provide the signed form meets the international and U.C.C. requirements for digitally signed documents including all of the overhead needed to meet these international and national requirements for validation of the signature and that the signed document has not been altered since it was placed on the site.

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