From: Andreas Schneider <aksdb@gmx.de>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: PDF Signature Fields
Date: Thu, 10 Mar 2016 11:04:17 +0100 [thread overview]
Message-ID: <48cc8851d6cb804e0bff8d3f08d72b27@chemnitz.dyndns.aksdb.de> (raw)
In-Reply-To: <56E03E48.5040609@wxs.nl>
Hello Hans,
after comparing eforms and the result of a document edited by Acrobat,
the relevant portions in the spec (PDF 32000-1:2008) are:
Section 12.7.4.5, with tables 232 and 233.
From what I see it should be possible to add a field /FT /Sig with and
without a /Lock dictionary.
The /Lock dictionary created by Acrobat also specifies the optional
/Type /SigFieldLock (eforms doesn't, but when in doubt, I trust Adobe
more than eforms ;-))
Here is an example from the PDF stream of a document manually forged
with Acrobat:
%% Object stream: object 167, index 37; original object ID: 475
<<
/AP <<
/N 188 0 R
>>
/DA (/Helv 0 Tf 0 g)
/F 4
/FT /Sig
/Lock 187 0 R
/MK <<
>>
/P 196 0 R
/Rect [
253.965
163.306
525.056
186.143
]
/Subtype /Widget
/T (Gehnehmiger Unterschrift)
/Type /Annot
>>
%% Object stream: object 187, index 57; original object ID: 495
<<
/Action /Exclude
/Fields [
(Einrichter Name)
(Einrichters Unterschrift)
]
/Type /SigFieldLock
>>
("Einrichter Name" is another Text Field --> /FT /Tx [...] /Subtype
/Widget [...] /T (Einrichter Name)
"Einrichters Unterschrift" is another Signature Field)
Best regards
Andreas
Am 2016-03-09 16:16, schrieb Hans Hagen:
> On 3/9/2016 2:11 PM, Andreas Schneider wrote:
>> Hello all,
>>
>> is there currently any mechanism in ConTeXt similar to the LaTeX
>> digsig
>> or eforms package?
>> I want to add a form field that can be digitally signed (which is now
>> already possible with Acrobat Reader, not just with Acrobat Pro).
>>
>> Additionally (like the mentioned eforms package) it would be nice, if
>> you could specify other form fields that should be locked once the
>> signature field is actually signed (according to the PDF spec this is
>> simply set via a dictionary).
>
> it's probably something trivial to implement so what are the relevant
> fields (paragraphs/tables/dics/fields in the pdf spec) .. i'm not
> going to reverse engineer some package but start from the spec
>
>> Anyway: can this currently be achieved with ConTeXt? If not: is there
>> any chance to get that feature added sometime? :-)
>
> so far i never bothered with anything signature (i must say that i
> never ran into such docs and it would not make them more valid to me
> anyway)
>
> Hans
>
> -----------------------------------------------------------------
> Hans Hagen | PRAGMA ADE
> Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
> tel: 038 477 53 69 | www.pragma-ade.com | www.pragma-pod.nl
> -----------------------------------------------------------------
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next prev parent reply other threads:[~2016-03-10 10:04 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 13:11 Andreas Schneider
2016-03-09 15:16 ` Hans Hagen
2016-03-09 15:39 ` Alan BRASLAU
2016-03-09 15:57 ` Hans Hagen
2016-03-09 16:04 ` Andreas Schneider
2016-03-09 16:20 ` Henning Hraban Ramm
2016-03-10 10:04 ` Andreas Schneider [this message]
2016-03-10 15:56 ` Hans Hagen
2016-03-14 13:55 ` Andreas Schneider
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