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Old 01-26-2004, 06:03 AM   #1
Daniel Han
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Registered: Aug 2003
Location: Kuala Lumpur, Malaysia
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decrypt pdf


hi.

i know this is a little out of this forum's topic,
but i was wondering what program is best used
to decrypt protected pdf files.
i've been looking around for far too long
for a free alternative but found none.

can somebody gimme some pointers?
 
Old 01-26-2004, 07:17 AM   #2
Bruce Hill
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Re: decrypt pdf

Quote:
Originally posted by Daniel Han
hi.

i know this is a little out of this forum's topic,
but i was wondering what program is best used
to decrypt protected pdf files.
i've been looking around for far too long
for a free alternative but found none.

can somebody gimme some pointers?
Are you talking about pdf files that have been encrypted with PGP, or
some other encryption program? If so, try gnupg. It's available for download ->
http://www.gnupg.org/(en)/download/mirrors.html for free, or course,
and there is a very good README file that you can either read from that
website, or from your comp once you unpack it. Website actually has many
HOW-TO's.

I am at this very moment just getting GnuPG setup on my Slack system to
use with KMail, and also for the purpose of encrypting files that I have
converted to .pdf format. So, maybe in a day or two I can be of more help,
if someone more knowledgable doesn't come along in the meantime.
 
Old 01-26-2004, 10:55 AM   #3
Daniel Han
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sorry that my first post about decrypting pdfs wasn't that
clear and complete. I was actually in a hurry.
anyhow, here's my situation:

I have a pdf document that contains a master password.
Since the master password was set by the original author,
i can't copy or edit portions of the doc. Plus, it's impossible for me to look for the author and ask for the password.

I've actually tried several Windows-based apps which are not free, to try to decrypt the doc but all those commercial apps
only let me decrypt halfway thru the doc (which is incredibly annoying!)

So, i was wonderin if there are any Linux apps that i can use to
remove/decrypt the doc's master password.
I've tried searching at sf.net and freshmeat.net, but
nothing came up.

anyone with an app in mind to do just that, do let me know.

thanks.
 
Old 01-26-2004, 08:33 PM   #4
Thymox
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You could try some of the console tools such as pdf2ps, pdftops, pdftopbm, etc. I'm affraid I haven't got any protected pdf files so I can't test it out for you.
 
Old 01-26-2004, 08:57 PM   #5
Daniel Han
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i've tried using those utils that you suggested.
the problem is, the fonts of the resulting doc
looks horrible.

Speaking of font de-uglification, how do i do that?

p/s -- does anybody know where i can
read up on the internal structure of pdf docs?
i am curious as to how the encryption system works.

pp/s -- i am seriously irritated by this master password
thingy. Commercial packages such as GuaPDF, Advanced PDF
Password Recovery and the likes are really putting me off.
that's why i am eager to know how the whole thing operates
and hopefully to circumvent it.

thanks a lot.
 
Old 01-26-2004, 09:03 PM   #6
Bruce Hill
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Quote:
Originally posted by Daniel Han
sorry that my first post about decrypting pdfs wasn't that
clear and complete. I was actually in a hurry.
anyhow, here's my situation:

I have a pdf document that contains a master password.
I would suggest that if you don't get any closer with the wonderful guys in
these forums, contact Adobe. They might not tell you how, but they should
know.

If you can provide some more details about it, maybe one of the guys here in
my city might know how. They don't pay for software - here, they say copyright
means "the right to copy," so they use copy CD's. Someone had to break a
lot of stuff to get them usable. Don't know anything else to tell you.
 
Old 01-26-2004, 09:07 PM   #7
Thymox
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Quote:
Originally posted by Daniel Han
PS -- Does anybody know where I can read up on the internal structure of pdf docs? I am curious as to how the encryption system works.
Contrary to popular belief, pdf is actually open. I believe it used to stand for Postscript Document Format before it became Portable DF. However, Adobe added many fancy things to it (which is why everyone think that Adobe own it) such as encryption, etc. I would guess that to find out about the inner workings of the encryption process, you'd have to ask Adobe, and probably pay for it and sign a NDA.

Ģ0.02
 
Old 01-26-2004, 09:17 PM   #8
Bruce Hill
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Quote:
Originally posted by Daniel Han
pp/s -- i am seriously irritated by this master password
thingy. Commercial packages such as GuaPDF, Advanced PDF
Password Recovery and the likes are really putting me off.
that's why i am eager to know how the whole thing operates
and hopefully to circumvent it.

thanks a lot.
I haven't read it in a coon's age, and don't know how much it will help, but here's a link ->
http://en.wikipedia.org/wiki/Portable_Document_Format
 
Old 01-27-2004, 03:34 AM   #9
Daniel Han
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you guys have been helpful.

i guess calculus is FAR EASIER than looking into PDF's
innards.

i'm already fed up wrestling with this master password matter
and i am thinking of stopping a while and sleep it off.

great idea. going right now.
 
  


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