Re: PDF encryption support in ConTeXt?

[Hans Hagen <pragma@wxs.nl>]

At 11:45 AM 8/14/2001 +0200, Giuseppe Bilotta wrote:

>This message is forwarded from the newsgroup "comp.text.tex".
>
>----------- Begin Forwarded Message -----------
>
>Subject: Re: Security settings with PDF files
>From: Heiko Oberdiek <oberdiek@uni-freiburg.de>
>Newsgroups: comp.text.tex
>
>On 13 Aug 2001 12:12:03 -0700, raider@mylaptop.com (Raider) wrote:
>
> >I read the pdfTeX manual and found no refference on how can I restrict
> >access to the generated pdfs.
>
>You need the latest pdfTeX (1.00a-pretest) with enabled
>encryption support, see the pdfTeX mailing list for details:
>   http://www.applications/pdftex/
>Package pdfcrypt provides a LaTeX interface and
>supports pdfTeX and VTeX.

So, actually you want to know if context supports pdftex encryption -)

Well, for the moment it does not, for several reasons:

(1) it's not part of standard pdftex (although thanh has now wrapped up 
encryption in a propper primitive)
(2) it's not garanteed to work
(3) it's spread all over the pdftex code, which makes it hard to maintain
(4) encryption can best be combined with serializing in a dedicated program 
[using xpdf lib]
(5) the encryption stuff interprets the object content which makes it 
dangerous code

[ad 5: on the pdftex list there has been some discussion about this and my 
suggestion was to *not* parse object content, but since the content would 
come from a macro package, to provide an on/off feature. One obstacle seems 
to be that hyperref has some hard coded stream sizes in macro code (kind of 
hackery, sigh). The patch was written while thanh was busy with his thesis 
so no real follow up took place.]

Last week at tug 2001 i discussed this with thanh. Since both encryption 
and tiff inclusion can break pdftex output, these features will be options 
that can be compiled in the code, but not defaults.

Maybe one of the programmers on this list sees it as an challenge to write 
a dedicated program for encryption; shoul dbe not that hard if you use the 
xpdf library.

Hans

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