Add specific protection to a pdf file

[spicydog]

I have created a pdf file and added all standard "pseudo-security" restrictions (prevent edit, copy, print etc.).

Now I need to give this file to someone but I don't want this person to give/distribute it to anyone else.

I understand that if I email the file (as an attachment) to the recipient, that attachment can be easily forwarded via mail to others, but fortunately I can personally hand the file to this one recipient on a USB stick or on a CD and would like to prevent this file from being copied/moved from the removable media onto a fixed hard disk (or forwarded via mail directly from the removable media).

Does anyone know a way to achieve all that?

I don't care if to accomplish this I have to use applications which are non-portable and/or non-freeware.

Additionally (but this is not a must), I would like to set an expiry date on this pdf file so that after a specific date (or after a specific number of days from the 1st opening or permit only a specific number of viewings) it will no longer open or show its contents.

If (at all) what I want to do is possible, I am well aware of the fact that nothing can really prevent this file from being tampered with, but I would at least try to make the free distribution of this file a bit harder (for a novice PC user) than just leaving the file totally unprotected.

Thanks for any creative suggestions

[joby_toss]

DRM protection. But are you willing to pay that much?
[Link removed at site owner's request]
This is just a software example, there are others equally expensive...

[spicydog]

...Are you willing to pay that much?... Thanks joby_toss but no thanks

I also looked at "PDF OwnerGuard" http://www.armjisoft.com/?page=purchase which in the Enterprise Server edition offers the "Automated USB Drive Binding" feature, which fits perfectly my needs... The only problem is that it costs (only) 4,259.94 EUR!!!!

How about this (homemade but probably effective) trick that just came to my mind?

I could burn the pdf file (with the "hidden" attribute) on the root of a CD with another hidden file (in whichever format) and then on the same CD I could also add a bat file (maybe converted to exe so that I can even give it an "acrobat-ish" icon) used solely to launch the (hidden) pdf file only if the other (also hidden) file is present (using the "if exist" string) in the same directory just as the (hidden/real) pdf file is... I hope my description is not too unclear

The novice PC user (especially not knowing about the existence of the 2 hidden files) will think that the actual file is the exe used to launch the (real) pdf file and eventually copy or forward to others that decoy-exe that (by itself) will be useless.

Any thoughts/tips/hints to polish up (or totally dismantle) my idea?

Thanks

[joby_toss]

Oh, but what you're saying now changes everything; you're willing to share an .exe file.



We have in TPFC Pdf2Exe free version, without the ability to specify the number of times the pdf file can be viewed.

Note: there are other cheaper pdf to exe converters; or you can use their trial versions that make your exe-pdf file expire in 30 days anyway...

[spicydog]

Now, that's what I call a CREATIVE tip Thanks joby_toss!

I will carry out some tests and see which approach works out best... In the meantime I have fiddled a bit with my .bat + (decoy) .exe + (sort of license) file and it seems to work quite nicely.

I have even "padded" the (decoy) .exe with some "useless ballast" to give it a size similar to the one of the real .pdf file.

While I carry out some more tests I'll be following the thread to see if some more nice hints will be posted

Thanks again

[spicydog]

Unfortunately PDF2EXE does not seem to work

My pdf file contains bookmarks/tooltips and other (necessary) stuff that gets totally stripped during the conversion.

[joby_toss]

Yes, because all these pdf to exe converters actually transform the pages into images and make an .exe "slideshow" (check the temp folder to see the image for the opened page in pdf2exe for example).
Just give him/her a very low resolution pdf full of watermarks.

[spicydog]

...all these pdf to exe converters actually transform the pages into images

Yes, that's what I also figured... Anyway your tip would have worked fine if my pdf file did not have those "extras", so thanks anyway.

Just give him/her a very low resolution pdf full of watermarks.

That reminds me of an old friend of mine who kept *only* dull knives in her kitchen being permanently afraid of accidentally injuring herself while cooking... No JT, that won't cut it (no pun intended!)

Please keep the brainstorm going, I am not 100% convinced that my "decoy.exe" trick will "fool" any individual above the age of 6

[m^(2)]

...all these pdf to exe converters actually transform the pages into images

Yes, that's what I also figured... Anyway your tip would have worked fine if my pdf file did not have those "extras", so thanks anyway.

Just give him/her a very low resolution pdf full of watermarks.

That reminds me of an old friend of mine who kept *only* dull knives in her kitchen being permanently afraid of accidentally injuring herself while cooking... No JT, that won't cut it (no pun intended!)

Please keep the brainstorm going, I am not 100% convinced that my "decoy.exe" trick will "fool" any individual above the age of 6

Won't foul professionals.
What you want to do is impossible, as simple as that and no money for a fancy DRM or smarts of your own will change that. If you're to deal with amateurs who are not determined enough to turn it to pros, or pros who don't care you may succeed, but lack of will is or capabilities is the only way that can protect your scheme.

And as to details of your scheme, I used to have showing of hidden files turned on permanently since I was a kid. And I know many amateurs using file managers that show file extensions. Little luck and an amateur can compromise your decoy.

[spicydog]

Won't foul professionals.
What you want to do is impossible, as simple as that and no money for a fancy DRM or smarts of your own will change that. If you're to deal with amateurs who are not determined enough to turn it to pros, or pros who don't care you may succeed, but lack of will is or capabilities is the only way that can protect your scheme.

And as to details of your scheme, I used to have showing of hidden files turned on permanently since I was a kid. And I know many amateurs using file managers that show file extensions. Little luck and an amateur can compromise your decoy.

As I wrote myself "I am not 100% convinced that my "decoy.exe" trick will "fool" any individual above the age of 6"... So (since the recipient of my pdf file is older than 6) we seem to be on the same page

I suspect that I will have to find a different approach altogether... I really wonder how firms handle that sort of aspect... I am pretty sure that at a certain point there are documents/files that one would want to prevent from being redistributed... I doubt that I am the first person who ever faced that dilemma.

Any thoughts?

[Midas]

Bear with me speculating a little: you could try placing the file inside a system special folder (somefolder.{RESERVED-GUID}; Google for list) and devise a link to refer to it by absolute file system path (but without the drive letter), which begins with something like \.\\... if I'm not mistaken.

Burn both to CD and, while easily viewable, it won't be straightforwardly copyable...

[tproli]

Interesting problem. Perhaps good candidate for a new application?

[spicydog]

Interesting problem. Perhaps good candidate for a new application?

Do you have something in mind?

[spicydog]

Burn both to CD and, while easily viewable, it won't be straightforwardly copyable...

Hey Midas, thanks! But don't you think that the file (from the CD) could still be attached to a mail and be easily distributed that way?

[guinness]

Any method you use to protect a PDF can easily be broken.