|
ru.linux
- RU.LINUX ---------------------------------------------------------------------
From : Olli Artemjev 2:5020/1354 27 Oct 2001 06:16:00
To : All
Subject : ?: gs & pdf_sec.ps (restricted/crypted pdf's) - как читать?
--------------------------------------------------------------------------------
GhostScript versions 4.02 and later надо сделать для чтения без ограничений
pdf'ов. Сделал как написано. GNU Ghostscript 5.10 (1998-12-17) , однако
теперь не знаю что делать дальше - сказав на консоли в иксах gs получаю
пустое окошко плюс собственную gs-консоль, ввожу там полный путь к pdf файлу и
получаю следующее:
GS> /tmp/file.pdf
GS<2>
А дальше я просто не знаю что вводить. :( Мне нужно всего лишь
переконвертировать в текст и, желательно, но не обязательно, отобразить
на экране. В man не посылать - с man я и сам разберусь за пару дней, а
хочется поскорее. ;)
- --------------------cut-------------------------
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0 Strict Level 1//EN">
<HTML>
<HEAD>
<META name="description"
content="Modifications to GhostScript to allow it to read encrypted PDF
files.">
<META name="keywords"
content="PDF encryption PDF security GhostScript viewing printing">
<TITLE>Encrypted PDFs</TITLE>
<LINK REV=made HREF="mailto:geoffk@ozemail.com.au">
</HEAD>
<BODY>
<H1>Encrypted PDFs</H1>
<P>When you give a PDF document an owner password, Adobe Acrobat
encrypts it so that you can't just remove the password from the file.
This web page provides the
modifications necessary to view encrypted PDFs with <A
HREF="http://www.cs.wisc.edu/%7Eghost/">GhostScript</A>.
<P>It used to be that source code like this was not permitted to be
exported from the US. Happily, the regulations have now changed,
and the code is unrestricted in most countries.
<H2>GhostScript versions 4.01 and earlier</H2>
<P>To allow versions of GhostScript from 3.33 through 4.01 to read
encrypted PDFs, you need to download the appropriate patch from the
list below, place it in the same directory as the files
pdf_base.ps and pdf_main.ps, and pipe them into
<KBD>patch -l</KBD>. If you don't have `patch' on your
machine, you can probably find a version at
<A HREF="ftp://ftp.gnu.org/pub/gnu/">your friendly GNU archive</A>.
<P>There are patches for versions:
<UL>
<LI><A HREF="patch-gs333-pdfsec">3.33</A>,</LI>
<LI><A HREF="patch-gs353-pdfsec">3.53</A>,</LI>
<LI><A HREF="patch-gs401-pdfsec">4.00 and 4.01</A>.</LI>
</UL>
<P>The last of these patches is quite a bit better than patches for
earlier versions.
<P>It is likely that these patches will not work if GhostScript is
compiled with 64-bit integers.
<H2>GhostScript versions 4.02 and later</H2>
<P>For these versions, things became somewhat simpler. All you need to do
is replace the file called pdf_sec.ps with the version
provided below, as described in the documentation.
<P><A HREF="pdf_sec.ps"><STRONG>pdf_sec.ps</STRONG></A>
<P>This file is version 1.0.4, which corrected a small bug involving
user passwords. Version 1.0.3 corrected a bug visible with the US
Copyright Office's Form TX. Version 1.0.2 added support for
versions 5.0 and later of GhostScript. Version 1.0.1 corrected
support for interpreters with 64-bit integers.
<H2>Usage information</H2>
<P>If GhostScript reports
<SAMP>****This file has a user password set.</SAMP>,
you can specify a password by setting <VAR>PDFPassword</VAR> to either
the user or owner password of the PDF file. On the command line, you
might say
<KBD>gs -sPDFPassword=apassword somefile.pdf</KBD>.
Inside GhostScript, you can say
<KBD>/PDFPassword (apassword) def</KBD>.
You can also put this in a file generated with pdf2dsc; put it just
after the line that says <SAMP>%%BeginProlog</SAMP>.
<P>I'm told that to do this with GSview, you go to the Options menu,
chose Configure Ghostscript, and place
<KBD>-sPDFPassword=apassword</KBD> in the Ghostscript option.
<H3>Lost Passwords</H3>
<P>Of course, to do this you must know the user or owner password of
the file. If you got the file from someone else, you will want to ask
them for the password. If it was your file and you've forgotten what
password you chose, you should take whatever documents you generated
the PDF file from, and re-generate it.
<P>Alternatively, you might try contacting <A
HREF="http://www.pwcrack.com/">PWCrack</A>, who can help you unprotect
the file.
<H2>Technical Details</H2>
<P>If you're interested in how the patch works, you should look
at version 1.2 of the PDF reference manual (available at <A
HREF="http://www.adobe.com/">Adobe's Web site</A>). My patches predate
this description, but they seem to conform to it exactly.
<H1>RC4-compatible and MD5 PostScript</H1>
<UL>
<LI><A HREF="rc4-source.ps">Source for an RC4-compatible algorithm
implemented in PostScript</A>.</LI>
<LI><A HREF="md5-source.ps">Source for MD5 implemented in
PostScript</A>.</LI>
</UL>
<P>If you have your browser set to automatically run PostScript files
with (say) Ghostview, you'll find doing that is not very interesting,
as they don't make any marks on the page; they just run some
self-tests.
<P><HR>
<P>Unless otherwise specified, these files are Copyright 1996-2000
<A HREF="mailto:geoffk@ozemail.com.au">Geoffrey Keating</A>, and may be freely
distributed with or without modifications, so long as proper attribution is
given and copyright notices are not removed.
</BODY>
</HTML>
- --------------------cut-------------------------
--
Bye.Olli. mailto(remove "NOSPAM"): olli@digger.NOSPAMorg.ru
*: Linux may become a power in a well directed hands.
--- Gnus/5.0803 (Gnus v5.8.3) XEmacs/21.1 (Bryce Canyon)
* Origin: Sunrise. (2:5020/1354.0)
Вернуться к списку тем, сортированных по: возрастание даты уменьшение даты тема автор
| Тема: |
Автор: |
Дата: |
|
?: gs & pdf_sec.ps (restricted/crypted pdf\'s) - как читать? |
Olli Artemjev |
27 Oct 2001 06:16:00 |
|
|
