Can we sign pdfs? Fill out pdf forms?

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

Hi,

I need to sign pdfs, and sometimes fill out pdf forms which also need to be signed. At the moment I get them, print them, sign them and scan them back in to return to the sender. I'd like to simplify that.

I know that on Windows and Mac OS your adobe software can sign the pdf, but I don't even know how that works exactly.

It would be really neat if there were an app which could handle all that.

Oh yeah, another thing. Some forms (all?) when you fill them out and print them have a bar of machine-readable gobbledygook on the page which lets the recipient of a printed pdf scan the data back in with 100% accuracy. That would be neat too.

Thanks.

Roman_Gruber · Posted: Wed Sep 14, 2016 10:42 am Post subject:

AFAIK on windows a very expensive software by adobe can do that. When you have such a license you may use wine to use that software in gentoo. You may set up a virtualbox with windows in a box with that software too.

Last time i checked for pdf reader editior featuers, 1-2 years ago, the features were very limited regarding open source software.

soka · Posted: Wed Sep 14, 2016 11:09 am Post subject:

You can use app-text/xournal to edit the pdf file and add a scanned image of your sign.

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

@Roman_Gruber,

Adobe reader for Windows (the free-to-use product) does what I'm talking about.

My wife's Windows 10 computer has all the features I'm talking about, using the free software. So as far as "very expensive licenses" no, nothing like that is needed.

The part about it being proprietary software, that I can believe.

Fitzcarraldo · Posted: Wed Sep 14, 2016 2:36 pm Post subject:

The way I do it is to open the PDF file in LibreOffice Writer (which, in turn, opens LibreOffice Draw), insert a PNG image of my signature with a transparent background (which I created previously using GIMP on a scanned image of my signature), drag the signature to the desired position on the page and resize it as desired, then save the file using 'File' > 'Export as PDF...'. I can also enter text in fields if the PDF file has editable fields.
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1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

@Fitzcarraldo,

That sounds like a really good idea. I'll give it a try. It should solve everything except the 2d/3d bar code part, which I expect won't get fixed.

While I strongly support the idea of both free and proprietary software, it's times like this I regret closed standards.

I use Linux for work, and unfortunately I need to deal with this one thing that requires "office" software. Nothing else I do professionally has anything to do with that.

There are sometimes documents like contracts which may require the use of Adobe. I'll see what this idea gives me, but I'm afraid I'll have to use Windows-based software for some of it.

Thanks.

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

The really frustrating part of this is that I have 3 Windows VMs. The license for them is for testing purposes only, so I can't use them commercially without changing the license.

Fitzcarraldo · Posted: Wed Sep 14, 2016 3:34 pm Post subject:

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

I don't know how to read the bar codes or how they're encoded.

One example I can think of is on many government forms, the bar code shows up on Windows when you print the document. I imagine it's the entire page of the form represented somehow, including fields and values.

I don't know how it's encoded, or how touchy it is. I know that:

On some forms I can fill out everything but I don't get the bar code that shows up on Windows when printed.
On some forms I can fill out most of it but some fields can't be changed that can be changed on Windows.
Calculated values in the forms usually fail.
Sometimes the form has built-in validation which will fail.
I don't know if other validation passes.
Some forms, like contracts, will probably require commercial software to sign, as they have features to ensure the data has not been modified.

Fitzcarraldo · Posted: Wed Sep 14, 2016 4:16 pm Post subject:

Interesting. I've just been doing some googling and found the following:

https://helpx.adobe.com/acrobat/using/pdf-barcode-form-fields.html

https://acrobatusers.com/assets/collections/tutorials/legacy/id_1781/2d_barcodes.pdf

It appears that the 2D bar code symbology can be PDF417, QR Code, or Data Matrix, as the user chooses, and the data can be encoded as XML or Tab Delimited, again as the user chooses.

If one chooses to encode the data as XML and the form has the fields e.g. Name, Department and Extension then the text encoded in the barcode would be something like the following:

mrbassie · l33t Joined: 31 May 2013 Posts: 781 Location: over here

szatox · Advocate Joined: 27 Aug 2013 Posts: 3150

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

A crypto key will not work for most of my documents. This is WAY beyond the technical ability of the usual recipients to deal with.

The documents I have to sign most regularly are going to the local office of a state government agency, and in the end it's going to be printed and stuck in a filing cabinet so the visible signature is necessary anyway. Not only do they not understand this sort of thing they literally can't allow any extra software to be installed on their computers, by decree from the bureaucracy.

I tried long and hard to get my coworkers, who are programmers, to do cryptographically signed emails and they looked at me like I was an alien. I'm positive that they understand what cryptography is, but don't see how it applies to their lives.

Roman_Gruber · Posted: Thu Sep 15, 2016 7:15 am Post subject:

There are some barcode readers for smartphones. Have you considered tinkering with those?

There are different standards last time I worked with barcodes. I programmed a handheld one barcode scanner to only accept one type of barcode.

Fitzcarraldo · Posted: Thu Sep 15, 2016 2:18 pm Post subject:

1clue,

Out of curiosity I used a barcode reader to read from my computer monitor the 2D barcode generated by the person in the Adobe video I referenced in my previous post. That barcode contains the following text (the presenter chose XML via the GUI of Adobe LiveCycle Designer when he was creating the form):

Fitzcarraldo · Posted: Fri Sep 16, 2016 11:03 pm Post subject:

1clue,

If you're prepared to use WINE, hopefully I have some good news for you. I have found a Windows application that works under WINE and, unlike Adobe Acrobat Reader DC, can be used free of charge in your office without needing to buy a commercial licence.

First I found PDF-XChange Viewer:

geki · Posted: Sat Sep 17, 2016 7:24 am Post subject:

Interesting question, current version of evince is said to be okay with filling out pdf forms.
The part about signing a pdf is to be implemented. Already in poppler, there are patches for evince, but poppler-glib needs fixing first.

https://bugzilla.gnome.org/show_bug.cgi?id=614929#c35
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geki · Posted: Sun Jan 15, 2017 8:27 am Post subject:

Hokay, poppler just verifies PDF signatures. Though, LibreOffice 5.3 or newer will be able to actually sign a PDF.
I wonder if signing PDF forms (or single form fields) is supported.

LibreOffice developer blog post:
http://vmiklos.hu/blog/pdf-sign.html
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charles17 · Advocate Joined: 02 Mar 2008 Posts: 3664

https://bugs.ghostscript.com/show_bug.cgi?id=697469 and https://bugs.ghostscript.com/show_bug.cgi?id=697334sound like even mupdf were providing forms filling and signing.
However it seems Gentoo ebuilds have it not enabled :-(

ct85711 · Veteran Joined: 27 Sep 2005 Posts: 1791

If you think think it may be an case that one of the ebuilds is missing a configuration and/or USE flag, may want to see what the config switch is and test to see if it causes any issues/fixes the problem. If it works, throw a bug report to have the ebuild updated with the new USE flag/configuration enabled. The second patch indicates there may be a patch out from Debian that possibly helps resolve this issue? May want to look into that, see if we need that patch or not.

charles17 · Advocate Joined: 02 Mar 2008 Posts: 3664

geki · Posted: Sat Jun 24, 2017 5:45 am Post subject:

JFYI, there are two bugreports to poppler to extract signature data[0] and actually sign a full PDF document[1] with work-in-progress patches. Qt5 frontend integration seems included.

[0] https://bugs.freedesktop.org/show_bug.cgi?id=99271
[1] https://bugs.freedesktop.org/show_bug.cgi?id=99416
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