Cheapest Way to Create Password Protected PDF?

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What is the cheapest way on Mac and Windows to create PDF files that are
encrypted using a PDF password?   These tools need to use the more modern
(later than version 7 of PDF I believe) Adobe PDF encryption technique that
cannot be easily broken.

I could of course buy the "Standard" version of Adobe Acrobat, but that
doesn't work well if you want to have many users share this capability.

There are many third party tools to help create PDF files, I'm just not sure
which - if any - support robust encryption at time of the file creation.
Ideally you would want the tool to remember the password settings in some
kind of profile so you could keep printing PDF files with the same settings
without having to type the password in repeatedly.


Re: Cheapest Way to Create Password Protected PDF?

W wrote:

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Use a utility that emulates a "PDF" printer that includes the password
feature.  Then you can Print the document from any application (that has
a print function) to the "PDF printer".  The PDF emulator should present
a screen so you can enter whatever password you want to use in a
particular .pdf file.

I use free Bullzip PDF Printer (
When I print a document (into a .pdf file) using it, there is a Security
tab present (before printing starts) to select 40-bit encryption
(Acrobat 3.0+) or 128-bit encryption (Acrobat 5.0+).  Other PDF print
emulators may provide longer key lengths.

Another popular one is PDFcreator ( /).  Like
Bullzip, it also uses the Ghostscript engine (see next paragraph).
Bullzip's installer will ask if you want to download and install Gscript
and, if elected, includes it during the install.  As I recall (from
years ago), PDFcreator requires YOU to do a separate download and
install of Gscript (which usually means Gscript gets installed in a
global location rather than under PDFcreator's own installation folder).
From their "learn more" link under Professional features tab, it also
has a max encryption key length of 128 bits.  The freeware version of
CutePDF Writer no longer includes Gscript so you have to separately
download and install it.  It also maxes at 128 bits for the key.  So it
looks like 128 bits might be it.  I've read that 256 bits is the max
length but I haven't used anything with it because I stick with
freeware.  There is some payware that will do 256-bit AES encryption,
like from Axpertsoft (never used it).

Many PDF printer emulators will use Ghostscript as the rendering engine.
Some have their own inbuilt proprietary engine.  It's up to you whether
or not you want a separate install of Ghostscript Lite on your host.
Bullzip and a few others will install Ghostscript under their own
installation folder.  That way it won't step atop of another global
install of Ghostscript that gets installed separately under its own
folder and used/shared by multiple programs.

Despite having a longer encryption key, do not use short or weak
passwords.  Acrobat 9 going to 256 bits did not make PDFs more secure. .

Re: Cheapest Way to Create Password Protected PDF?

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The Axpertsoft tool is interesting because of 256-bit support.   A $25 cost
isn't material to me.   I hope they implement a print driver in addition to
a standalone application.

What is really confusing however is that the same company sells a tool to
remove all security, even if you do not know the password:

How exactly do they pull off that trick, and what is the point of Adobe's
encryption if it is so easy to defeat?

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Password length is always critical.  I always figure any password under 12
characters and not using at least a few non standard characters is going to
be crackable by brute force.

But this article seems to be making the additional point that version 9 of
PDF with 256-bit encryption made it greatly easier to guess at passwords.
Does anyone know:

1) Was this defect corrected in a later version of PDF?

2) What is the number of characters in a password that would be required to
overcome the version 9 256-bit defect?


Re: Cheapest Way to Create Password Protected PDF?

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I have no idea what the weakness is, but I could well imagine a weakness
such that an infinite length password would be no stronger than a 2
characer password. 256 bits is by far enough strength for a password, if
the encryption is at all decent. If it is not 100000 bits is not enough.
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Re: Cheapest Way to Create Password Protected PDF?

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Here is what I found about PDF:

* There is a feature to restrict printing and editing in a PDF.  This can be
broken instantly by many software tools.  It's not a robust feature.

* 40 bit encryption (RC4) can be defeated by brute force within two days on
any modern computer.   There are some clever programs out there that use
cheat tables and GPUs to break the 40 bit encryption in less than 30

* 128-bit AES encryption can be beaten by brute forcing the password that is
specified during encryption as the "file open" password.   The usual rules
on such things apply, and probably a password that is complex and longer
than 12 characters will be very hard to brute force.  So this is probably

* 256-AES encryption had some defect in the early Adobe implementation that
made it very easy for GPUs to sample huge numbers of hashes per second.
One would assume that a password of some length would still be secure, but I
have not done the math to see how many characters that password would need
to have.

For PDF I think you want to use AES with 128-bit and a very long and complex
password, and you will be fine from everyone except a government.  And if
you have something a government wants you have bigger problems than how to
secure a PDF file.   For sending bank statements to my relatives or a love
letter to my girlfriend, I think 128-bit AES works just fine.

So - in light of these refinements - what I want is to find a PDF printer
for Windows and Mac that can create profiles to print to PDF and do the
encryption at the same time.   That way if I need to print 20 bank
statements, I don't need to manually specify a password 20 times.

I found many utilities that will print to PDF using 40 and 128 bit RC4, but
I did not find any yet that will print to AES 128 bit.   And I definitely
did not find any that would let you specify a profile to bypass manually
supplying the encryption password.


Re: Cheapest Way to Create Password Protected PDF?

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This tool appears to meet most of my requirements, and incredibly it is

Wow, how does anyone survive in the software business.


Re: Cheapest Way to Create Password Protected PDF?

W wrote:

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That's one of those that I mentioned.  I used it for awhile but don't
remember why I switched from it to Bullzip's PDF Printer.  I suspect it
was an ease-of-use reason and that extra features, if any, in PDFcreator
weren't required by me.

I don't remember a "profile" or template feature where you could call it
to automatically print many documents and without having to manually
specify a password for each document; however, back then, I would not
have needed such a feature so I wouldn't have looked for it, and I
wouldn't remember about it since I never used it.  Of course, in that
time, PDFcreator has probably had updates which included feature

I just checked and Bullzip PDF Printer has "option sets".  Never used
them.  Didn't even realize it had them.  Apparently you can define
option sets in Bullzip like you can define profiles in PDFcreator.
Later when you print from an application (and select Bullzip PDF
Printer), you can select amongst the default or custom option sets.

As I recall, PDFcreator lets you run it from a command line.  That means
you could write a batch or script file to have PDFcreator do what you
want within a list of commands and parameters to each.  For example, in
a batch file, you could use a for-loop to run through every document
within a folder to "print" to a .pdf file with the parameters you
specify on the command to run PDFcreator.  It has a COM interface to let
you write scripts that call PDFcreator as function calls.  Bullzip has
an API that supports both .Net and COM calls and also has a CLI
(command-line interface to run it by calling the program with
parameters).  Never got this deep with either product since creating
PDFs has been an occasional and single-doc thing with me.

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