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XFA Form signature

forums_noreply@adobe.com — Wed, 18 Jun 2014 15:24:42 GMT

Hi,

My company developed a tool to sign PDF and it's working well. Today, we were submitted a XFA Form PDF, and we cannot see the signature field nor is the signature bar available.

We'd like to know why is Adobe Reader ignoring the signature?

Is it possible to sign a XFA Form with regular PAdES (and not PAdES part five)? If so, will Adobe Reader validate such signature?

xref with object number greater than trailer's size value

forums_noreply@adobe.com — Thu, 24 Jan 2013 10:36:55 GMT

Hello,

a client sent to us a PDF with a strange xref table. Here is what it looks like:

xref
0 55
%% standart xref entries
200001 5
0000052507 00000 n
0000052793 00000 n
0000053079 00000 n
0000053365 00000 n
0000053727 00000 n
trailer << /Size 55 /Root 54 0 R /Info 53 0 R >>
startxref
54691
%%EOF

Those extra five objects are well formed link annotations. According to the standart, I should ignore those objects but all the tools I used to inspect the document found no problem in it.

So what should I do: concider /Size as the upper limit for object numbering in the document, or reach every reachable object, no matter what its object number is ?

PDF cross-reference streams

forums_noreply@adobe.com — Thu, 05 Jan 2012 18:40:57 GMT

Hello,

I noticed a behaviour I don't understand with some PDFs. They are hybrid-reference file where both cross-reference sections carry the same informations (there are 9 meaningful objects and the 9 are referenced by both sections).

When I sign the document twice, the second signature invalidates the first one. This seems to be due to the copy in the update trailers of the reference to the original cross-refernce stream, i.e. :

trailer
<</XRefStm 78305/ [...]>>

Is this a bad practice?

Page rotation and signature field

forums_noreply@adobe.com — Wed, 05 Oct 2011 12:48:29 GMT

Hello,

I'm requesting some help because I spent too much time comparing my PDFs to see where I am wrong.

I got a document with a clockwise rotation of 90 degrees for every pages. The conforming readers apply the

rotation to display the content in a readable fashion.

So, when I sign the document (with a visible signature field), the signature visual representation is rotated. I got back to ISO 32000-1

and discovered the MK dictionary of widget annotations (table 188).

Here is an example of the widget annotations I'm producing now:

5651 0 obj
<</MK <</R 90>>/F 4/Type /Annot/Subtype /Widget/Rect [100.0 475.0 356.0 731.0 ]/FT /Sig/DR <<>>/T (Sign5929838)/V 5649 0 R/AP <</N 5661 0 R>>/P 5629 0 R>>
endobj

But the signature representation is not correctly aligned.

I compared to what Acrobat 8 Professional is doing. Until now, I found no differences, but those signatures are correctly aligned.

5636 0 obj
<</Rect[39.8122 525.182 153.319 702.22]/Subtype/Widget/F 132/P 5634 0 R/T(Signature2)/V 5660 0 R/DA(/MyriadPro-Regular 0 Tf 0 Tz 0 g)/FT/Sig/Type/Annot/MK<</R 90>>/AP<</N 5637 0 R>>>>
endobj

(Acrobat is re-ordering objects before saving the file)

Well, I think I need some fresh look to understand when I went wrong.

Here are the complete files:

http://www.terafiles.net/v-121441.html (by me)

http://www.terafiles.net/v-121442.html (by Acrobat)

Signature field rotation

forums_noreply@adobe.com — Tue, 27 Sep 2011 14:45:03 GMT

Hello,

I found out that you can rotate signature fields the same way you rotate pages (using the MK dictionary of the widget annotation).

I'd like to know if it's possible to make a random rotation (i.e. 45° for example) or have we to stick to the multiples of 90° ?

Standard 14 fonts embedding

forums_noreply@adobe.com — Wed, 29 Jun 2011 16:33:40 GMT

Hello,

I read several times carefully the table 111 of ISO-32000, and always bear in mind that "Beginning with PDF 1.5, the special treatment given to the standard 14
fonts is deprecated. Conforming writers should represent all fonts using a complete font descriptor. For backwards capability, conforming readers shall still provide the special treatment identified for the standard 14 fonts.".

However, I found a conforming writer that produces 1.6 spec PDFs without embedding the standard fonts. The disturbing point is that it's an Adobe product.

http://www.adobe.com/security/pdfs/entrust_sample_doc.pdf

Maybe I'm missing something, but I can't see what.

So, here is my question: will my soul burn in hell if I'm guilty of writing a PDF writer that still gives to the standard 14 fonts their special treatment?

Programmatically list the fonts used in a PDF

forums_noreply@adobe.com — Thu, 12 May 2011 08:57:54 GMT

Hello.

I want to make a list of all the fonts used in a PDF. After reading (again) the ISO-32000 standard, I tend to think that the only way is to cycle through the pages and list the fonts used in each one.

Is there any other (and faster) way to do this?

Dynamic digital signature appearance

forums_noreply@adobe.com — Tue, 09 Jun 2009 09:30:03 GMT

I searched but it seems like the subject hasn't been treated.

Ok, I've read "Digital Signature Appearance" by Adobe, and find out how to put my own image when displaying digital signatures.

Looking at some tutorial from the iText authors, I saw that it is possible to specify different images to display on the signature validation

status.

This is a very cool feature, but unfortunately it is not documented at all in Adobe's documents... (I had to found a patent description document

to get more info)

Here is what I've discovered: the signature appearance is organized in several layers (4 defined by Adobe, the others by the document producer),

painted sequencially when showing the document.

What I'm looking for is the way to the various layers are used: one may be used when the signature validation status is unknown, another when

the validation was successful and a last when it failed.

For now, all my layers are painted, no matter of the signature validation.

(description in "Dynamic preview of electronic signature" is on page 9)

Adobe 9.1 error 0x20c

forums_noreply@adobe.com — Mon, 08 Jun 2009 13:27:46 GMT

Hi everyone!

I got a problem when signing PDF files.

I wrote a piece of code that performs the signing, and until recently all worked fine!

Then, I switched to Reader 9.1, and now some of my signed documents are not validated:

an inner ciphering library error occurred, with an error code of 0x20c (this is reader's message).

This is quite disappointing, and I cannot find any verbose explanation of what's wrong with those PDF.

If any one have an idea of the signification of that code (or a place where I can find it), any help will

be gratefully appreciated.

Thanks in advance!