Unable to remove PDF signature to conduct OCR

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LondonZ1
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Unable to remove PDF signature to conduct OCR

Post by LondonZ1 »

Hi,

I have an apparently-unsecured PDF, which has no security and no password, but which does have document permissions enabled to prevent editing. Please see photos here:
Pic 1.png
Pic 2.png
I know that I can "Print to PDF" to generate a new PDF, but this seems ludicrously inefficient: there must be a simpler way to remove the signature. There are also lots of online tools which will do this for me at no cost, e.g. https://www.pdf2go.com/unlock-pdf, but - again - this seems very convoluted as it is a function which PDF-XChange surely must have somewhere.

How can I remove the restrictions in a non-password protected PDF, so as to enable me to conduct OCR? Many thanks.

As background, these are documents which I not only have the right to edit, but an obligation to do so: they are witness statements for a court hearing, and the court's rules require that we OCR them before putting them into a bundle. For example, see: https://www.judiciary.uk/guidance-and-resources/general-guidance-on-electronic-court-bundles: All pages in an e-bundle that contain typed text must be subject to OCR (optical character recognition) if they have not been created directly as electronic text documents. This makes it easier to search for text, to highlight parts of a page, and to copy text from the bundle.
LondonZ1
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Re: Unable to remove PDF signature to conduct OCR

Post by LondonZ1 »

Just to update this: as well as being able to unlock it online, I have downloaded the trial version of the following desktop software which can also unlock the document: https://www.ilovepdf.com/desktop

I say unlock, but that's really a misnomer, as I have full open/read/print privileges already - I'm just trying to remove the stupid signature which is preventing me from conducting OCR. It's a technical annoyance, and one which I'm surprised is so difficult to fix. After all, the purpose of the signature is to verify the document's authenticity - as long as I cannot reapply the signature afterwards (which plainly I cannot do, as I don't have the private key), there's no harm in me removing it.
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TrackerSupp-Daniel
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Re: Unable to remove PDF signature to conduct OCR

Post by TrackerSupp-Daniel »

Hello, LondonZ1

The document is locked to prevent editing by the signature, as indicated at the bottom of the security details window in your first post. I am afraid that if you did not place the signature, or do not have a copy of that signatures certificate located in your windows system store, you will not be able to remove it. Only the original signer has the right and ability to remove a signature from a docuemnt.
While I understand your job requires it, I am afraid that our hands are tied and we cannot assist in any way to circumvent the security which a signer or creator has placed.

In this case, my advice to you would be to contact the individual whom you acquired this document from, and ask them for a copy of the unsigned version, so that you can make the required edits. Note that while printing to PDF may work to remove signatures, it can also have the effect of removing/converting text content, and may rarely cause damage to the file leading to eventual document corruption. Printing a PDF to PDF should be avoided whenever possible to prevent that outcome. Likewise using third party tools to forcibly remove a signature can cause similar damage to the file. The best case scenario here is getting a clean copy of the file to work on, instead of "breaking" the security on this one.

Kind regards,
Dan McIntyre - Support Technician
Tracker Software Products (Canada) LTD

+++++++++++++++++++++++++++++++++++
Our Web site domain and email address has changed as of 26/10/2023.
https://www.pdf-xchange.com
Support@pdf-xchange.com
LondonZ1
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Re: Unable to remove PDF signature to conduct OCR

Post by LondonZ1 »

Thanks Daniel, that's helpful. I understand why Tracker Software wouldn't want to get involved in circumventing the Adobe PDF specification, including signature security. If possible however, would you be able to provide me with a little more information regarding - or perhaps suggestions how I could research further myself - the disadvantages of the two courses of action we have discussed please, being:

1. Printing to PDF.

2. Using third party software to render the PDF editable despite the signature.

The reason I ask is that I'm a lawyer, and the party which signed the documents is the court office, when 'sealing' them, i.e. accepting them as offical documents on the course file. They are also the same people who (quite reasonably) require that we OCR all PDFs before putting them into a trial bundle. I strongly suspect that no one has yet highlighted the issue created by the 'sealing'/PDF signature process when applied to non-OCRed documents*. I am sure that they will be open to any constructive suggestions that we make to them, but I will however need to justify why courses of action (1) and (2) above are inadequate and/or carry technical risk.

Thank you again for your time and advice.


* This issue wouldn't occur of course if parties ensured that their submissions to the court were already OCRed prior to filing, but that ship has already sailed.
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TrackerSupp-Daniel
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Re: Unable to remove PDF signature to conduct OCR

Post by TrackerSupp-Daniel »

Hello, LondonZ1

First, Adobe handed the PDF specification over to the ISO board many years ago, it is no longer dictated by adobe, and is simply the "PDF Specification". Adobe is as much at the whims of the ISO as we are in this area now.

As for the disadvantages of the methods to forcibly remove security. There really is not much more to it than what I mentioned before. The two methods are both rife with potential issues that are caused by the existence of security which encrypts the document information in order to prevent editing. While it is possible to circumvent (brute force) remove a digital signature, there is no guarantee that it was removed properly, nor that all the encrypted data was properly recovered. This can leave fragments in the file leading to bloating document sized, and potentially corrupting content if it is edited at all while the damaged data is still associated to it.

In brief, there is no way to safely identify if the document has been damaged by either process until you have been using the file for some time, and made a large enough number of edits to catch the error manually as it appears. And for that reason, we highly recommend that you do not use these methods to remove security. If it is ever possible, you should try to acquire the original document before security was applied, assuming you are unable to remove it through the proper channel. That channel would be using the locally installed certificate to "unlock" and remove the encryption applied by a signature, as our "remove signature" function does.
LondonZ1 wrote: Wed Feb 08, 2023 4:02 pm This issue wouldn't occur of course if parties ensured that their submissions to the court were already OCRed prior to filing
Out of curiosity, have you tried using the "select text" tool within these documents, to identify if there is already text present on the pages? I find it quite odd that any entity, especially a court with such strict rules, would lock these files without running first OCR on the document themselves. That said, it is also quite possible that there were simply unaware of what digitally signing actually does to the file from a security perspective.
Historically speaking, a physical signature would not prevent these actions from being performed, and for quite a long time, many individuals and applications used a "signature stamp" to digitally sign a document (without actually applying a certificate), which would not lock the document in any way. It could be that the courts think they have done this ("signature stamp" the file), and have accidentally used the much more restrictive certificate function to "digitally sign" their documents due to the similar naming of these two functions in modern applications.

Kind regards,
Dan McIntyre - Support Technician
Tracker Software Products (Canada) LTD

+++++++++++++++++++++++++++++++++++
Our Web site domain and email address has changed as of 26/10/2023.
https://www.pdf-xchange.com
Support@pdf-xchange.com
LondonZ1
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Joined: Mon Sep 28, 2020 2:42 pm

Re: Unable to remove PDF signature to conduct OCR

Post by LondonZ1 »

Thanks for this, Daniel. In answer to your question:
Out of curiosity, have you tried using the "select text" tool within these documents, to identify if there is already text present on the pages? I find it quite odd that any entity, especially a court with such strict rules, would lock these files without running first OCR on the document themselves. That said, it is also quite possible that there were simply unaware of what digitally signing actually does to the file from a security perspective.
Some documents were apparently OCRed prior to submission; some weren't. My main concern is the former, as we do need to OCR them. Unfortunately, court staff are far too busy to realistically do anything other than their mandated tasks - and even then we sometimes need to politely chase them, as they are very busy.

I think you're correct in diagnosing the root cause as follows:
Historically speaking, a physical signature would not prevent these actions from being performed, and for quite a long time, many individuals and applications used a "signature stamp" to digitally sign a document (without actually applying a certificate), which would not lock the document in any way. It could be that the courts think they have done this ("signature stamp" the file), and have accidentally used the much more restrictive certificate function to "digitally sign" their documents due to the similar naming of these two functions in modern applications.
I will discuss next steps with our IT team here, and go from there. Thanks again for your time and assistance.
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TrackerSupp-Daniel
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Re: Unable to remove PDF signature to conduct OCR

Post by TrackerSupp-Daniel »

Hello, LondonZ1

Glad that I was able to help in some small way. I hope that sharing this knowledge helps to streamline the process for everyone down the road.

Kind regards,
Dan McIntyre - Support Technician
Tracker Software Products (Canada) LTD

+++++++++++++++++++++++++++++++++++
Our Web site domain and email address has changed as of 26/10/2023.
https://www.pdf-xchange.com
Support@pdf-xchange.com
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