Re: PDF Digital Signatures

From: Mojca Miklavec <mojca.miklavec.lists@gmail.com>
To: Hans Hagen <pragma@wxs.nl>
Cc: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: PDF Digital Signatures
Date: Tue, 20 Mar 2012 20:23:04 +0100	[thread overview]
Message-ID: <CALBOmsbB62kjmPQ9jdccykrxABHBdvQ1NTuE918_XM4rPr7xQA@mail.gmail.com> (raw)
In-Reply-To: <4F67AF4D.9030709@wxs.nl>

On Mon, Mar 19, 2012 at 23:12, Hans Hagen wrote:
> On 19-3-2012 22:08, Mojca Miklavec wrote:
>>
>> Out of curiosity: is inability to create password-protected PDF files
>> with pdfTeX/LuaTeX due to legal issues or due to nobody caring enough
>> to implement it?
>
> it's not worth the trouble. Afaik it's a second pass issue and would
> complicate the code much.
>
> Just use qpdf to do it ... pretty fast.

If qpdf exists it is probably not a legal issue to do password protection then.

But from the same perspective ... one first needs PDF to be (almost)
finished before being able to sign it. One needs to read as-good-as
the whole PDF, read the certificate from somewhere on the disk and
then sign with that certificate. If certificate is password-protected,
one also needs to provide the password somehow.

The usecase would be sending documents to officials (proving that the
document really comes from the person claiming the ownership). But it
is also true that in principle one can sign emails with PDF
attachments. It is not the same, but it comes close. Another usecase
could be, say, sending invoices to clients.

We have a company that sells crappy software for signing PDFs and XML
for over 1000 EUR per version per browser per OS (each new version for
each supported browser on a single OS costs that much; and they have a
lot of clients). And of course it never works since of course it only
supports Mac OS X 10.6 (10.7 still doesn't work), on Windows only IE 7
or Firefox 3.6 (latest Firefox won't work and it is awfully difficult
to find the old versions), on Linux probably a similar story (never
tried). And that is the only possible way to send any document to the
government. On the other hand they could just as well have used some
standard tool and it would work out of the box. So much about signing
...

Mojca
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