Securing a pdf file 2

[Inky]

I need to e-mail a printable pdf file to customers on a regular basis. I set Acrobat security on the files to allow printing, but deny changing the file in any way. The password is set also. I just discovered that you can still open the pdf and export as an eps or postscript without needing the password. This defeats the purpose of the security. My customers need to be able to print document proofs on a laser printer, so I can't deny printing. Does anyone have any suggestions that might help?

 

[Murgle]

All I would say is that it is impossible to prevent data extraction from a pdf if the user is determined enough to do it. If the security has been set to allow printing, your customer can print off a laser proof, then scan it using OCR software and hey presto! - an illegal copy with no security.
Even if printing is disallowed, you can do screencaps for the document then paste them together using very basic 'paintshop' style apps.

These are very basic ways of doing it - there are much more sophisticated methods than this, but it demonstrates that if you can see it on screen, you can extract data from it... Ahhhhh, I see you have a machine that goes Bing!

 

[blueark]

I would add that, if they have a postscript printer driver, then there's nothing stopping them from printing to a file rather than paper. Once that happens, you've got a postscript file, and that's not the most difficult thing to open. But on the positive side, have you ever opened such a file? The text is broken up into small fragments making it extremely difficult to do any major edits.

What are your security concerns anyway? You want your customers to be able to view the file, print it, but not... edit it? Copy it? As Murgle says, if it's on screen, it can be edited. If it can be opened, it can be emailed. If it can be printed, well that just gives another option, unfortunately.

 

[Murgle]

Just one small addition to all the above - even if you are allowing a user to only view your document, even if they could do this without downloading a copy of it to their cache (which they can't - it has to be cached to be viewed), then the information contained within that document is no longer secure. What should be secure, however, is YOUR copy of the document. The only way to divulge your information and still make it secure would be to shoot your customers after they read it, which I guess would defeat the object...... Ahhhhh, I see you have a machine that goes Bing!

 

[Inky]

My basic concern is that I don't want to do all the design work and then have the customer take that postscript and use it to create film and print their own stuff. (I work for a specialized print house.) It looks like trust is a key component of this sort of thing. I have to trust that they won't take my file and job it out to another printer or do it themselves. If I print an EPS, I can open it in my imposition software and it looks good to go-ready to send to film. I didn't rip the test file, though, so I'm not sure if the resolution would really be high enough to use effectively. Murgle has a good point-MY copy should be secure. Thanks for all your help.

 

[blueark]

...and you have a good point too: resolution. Many documents on the internet are unusable for commercial printing because the resolution is too low, or the jpeg compression is too high, but it's good enough to read off screen.

 

[mackers2]

I don't know if this is helpful - but what I've done to stop people using a printed version when I don't want them to is to put a form field on the document that has some text on - I use "Invalid Form - Do Not Use" that goes right across the whole page. I set the field to invisible, but prints so it doesn't show on the screen.
Regards
Alasdair Macdonald