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Question

What would be the best way to secure a filled pdf form

Forum|Forum|4 years ago
January 8, 2022
4 replies
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Hi,

i am trying to stop counterfieting of my company issued documents. i am well aware its almost impossible to stop that, but i want to make an effort to makeit less easy. We issue certificates to clients, these certficates go through many hands everyday and people photoshop some data from the one that reached their hands to benefit themselves. To fight this we are in the process of implementing QR codes on documents. This wouldnt eliminate the issue but reduce it to a great extent. Previously we were making the certificates in excel and publishing to pdf but our new system would just involve PDF forms. There would be pdf form templates which would be filled by our staff and signed digitally and then forwarded to clients. I do not know how the digital signatures protect the document. I guess they only show if the document has been tampered with. but this wouldnt help my cause. i am looking to do something like flattening the document first and then adding a digital signature. this way even if the document is tampered with, the form isnt readily available to edit. and the digital signature after that would give a 2nd layer of security. I am not sure if this is the best and fastest way to do this.

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Thom Parker

Community Expert

You're idea is the best one. Flatten to remove form fields, then sign with a certificate to verify integrity.

There is no way to truly secure any content in any format if you allow people to view it. Viewing by definition means that the content is available. So it all comes down to your security goals. How high of a fence do you need? If all you really need is integity, then a certificate signature is the best option.

Thom Parker - Software Developer at PDFScriptingUse the Acrobat JavaScript Reference early and often

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Fowzan22558090s6v8Author

Known Participant

i tried this. flatten the document before adding the digital signature. but any pdf editor can easily edit the document in this state. it would just require to select and delete text and then add whats required. the signature would be voided, but most of the end users wouldnt be able to understand that. moreover the document template can be easily replicated in this state. still feel the only solution to my scenario is converting to image and then adding digital signature. but this would take alot of time, considering the volume of documents. i hope i am wrong and there is a better way to achieve my goal in the fastest way possible

Luke Jennings3

Community Expert

You can use a preflight fixup to quickly convert the page contents to an image, (Tools> Print Production> Preflight> Fixups (the blue wrench icon). You can duplicate the fixup from the fly-out menu and edit it, if you want to change the image resolution. You can also add the preflight to an Acrobat action using the Action Wizard (Tools> Action Wizard) where you can quickly apply the action to a file, or a folder of files. Tip: you may need to export the preflight to your desktop, then import it back into Acrobat (also from the fly-out menu) in order for it to appear in the Action Wizard list.

Tip 2: to make the image harder to edit, use a ghosted, non-repeating background or gradation.

Fake_certificate.pdf

Nancy OShea

Community Expert

Flatten the signed PDF in Photoshop and send clients a JPG. They can't easily tamper with an image.

Nancy O'Shea— Product User & Community Expert

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Test Screen Name

Legend

But people CAN easily tamper with an image. It takes seconds or maybe minutes, especially if motivated. The solution is to use a Digital Signature and tell people certificates (from a given date) are valid only if digitally signed. DON'T use a signature appearance - people will just look at that and trust it.

T

Test Screen Name

Legend

PS: to emphasise: the point of digital signatures, and the reason it protects against faking, is nothing to do with security. It's about authentication. Any change, of any kind, breaks the digital signature.

That said, if you are offering certificates proving eg attending a course or passing an exam, I'd say the days of certificates are gone. As an employer, I'd want proper proof. Proper proof would mean a searchable database on your own web site. People wouldn't search for name (that violates privacy laws) but would search for a code number that you give out (perhaps on a kind of certificate in fact). The potential employer, etc, would be given the number and could check the name it yields. Important: to protect privacy you must not just give out consecutive numbers, but a long random string.

Dave Creamer of IDEAS

Community Expert

As @try67 mentioned, forms can be unsigned by the signer.

Flattened or printed-to-PDF forms are even easier to edit since the text become "regular" PDF text.

If it can be opened, it can be screen captured; do it on a uHD monitor and you will get a reasonable facsimile.

Are the people you send the PDF to cooperating in the copying? If not, you can add a password to open the file so only they can open it.

You could look into enterprise-level security that binds the PDF to a particular computer or make the PDF "phone home" to check it validity. There are companies out there, including Adobe partners, who can help you.

On a lower level, I would consider printing out the certificates on security paper and mailing them--this will prevent copying or scanning. (I do not believe it will prevent photos, but you can make it more difficult. It will make a nicer impression on the client too.

Consider putting a line on the certificate to call (preferably an 800 number) to check the validity of the owner. Consider serializing the PDFs too. Someone could call and give the serial number and name on certificate--the answer could be simply the certificate "is valid" or "is not valid".

David Creamer: Community Expert (ACI and ACE 1995-2023)

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Fowzan22558090s6v8Author

Known Participant

we are currently printing on regular paper. security paper is not an option as the volume of documents we issue is huge and it would be a very expensive solution. infact printing on paper adds overhead as it needs to be physically delivered, where as in our case a digital document would do the needful. thats the main reason we are going digital. password protection wouldnt help at all as usually the clients themselves counterfeit the documents to change the validity of the document. enterprise level security is also out of question as we are a very small firm with confined budget. converting the document to image would help but i am in search for a better solution.

Dave Creamer of IDEAS

Community Expert

Since you have to let the client print it, there isn't much you can do to prevent copies.

What you can do is make it difficult to reproduce.

Here is what I did:

Create the certificate in InDesign (with AI art).
Name, date, class, etc. are text variables. The student name variable changes both the large name and the background name at once.
I converted the text to raster with a Transparency Flattener preset.
Export out to PDF.
You can also export to a PNG if you wish.

Samples posted (without any security). Also, I did not add my signature graphic since it's a public post.

David Creamer: Community Expert (ACI and ACE 1995-2023)

CertificateOfCompletion2022r.pdf

JR Boulay

Community Expert

Signing a document causes it to become flattened, and it is no longer editable.

But that does not prevent the copy and paste.

Acrobate du PDF, InDesigner et Photoshopographe

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Fowzan22558090s6v8Author

Known Participant

well i tried that before i posted this thread. but it didnt work for me as you say. i am still able to edit the form as usual after signing the document. what am i doing wrong?

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