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We have a very specific use case for an application we're developing, where a user will be presented with a PDF document, which they can print off. However, we need to be able to restrict the PDF so it can only be printed off once. Does anyone know if there's a way to restrict the number of times a PDF can be printed.

I'm aware the PDF spec has lots of security features, but I've not found reference to anything like this before.

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Folly –  dlamblin Sep 7 '09 at 16:18
    
Tell me about it ;-) I've been looking at the possibility of using a java applet to handle the printing instead of a PDF, seems like there may be some options down this route, but still doesn't look easy. –  pauldunlop Sep 7 '09 at 16:21
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In the end, likely neither you nor your client will be happy with how this turns out. Might as well be upfront about it. –  emgee Sep 7 '09 at 17:52
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Agreed. Just tell him it's not possible. –  alex Sep 7 '09 at 19:04
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You should read and understand the question and answers at superuser.com/questions/14224/how-to-explain-drm-cannot-work ... –  Chris W. Rea Sep 7 '09 at 19:18

12 Answers 12

up vote 5 down vote accepted

Adobe use their Adobe Content Server to protect eBooks and PDFs along with Adobe Digital Editions (their free eBook and PDF reader) on the client side. This allows the distribution of PDFs with more flexible security options than the usual standalone PDF will allow. For example, documents can be time limited or allow only a certain number of pages to be printed.

This may well be a sledgehammer solution to your problem as I've no idea of Adobe's pricing for this product or whether is's practical for a small number of documents. It's used by the likes of the British Library (until recently anyway) for electronic inter-library loans which expire after 2 weeks and only allow the article to be printed once.

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Very interesting, I wasn't aware this solution existed. I'll definitely have to check that out. Thanks! –  pauldunlop Sep 8 '09 at 8:50
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And I'm sure end users are very pleased when their printer runs out of ink during their one and only chance at printing. –  RBerteig Sep 12 '09 at 2:35
    
At work, I've once bought a book that required this. Never got it to even show in Adobe's Digital Editions. That may very well have been due to the website that sold me the book, as that website somehow needs to signal Digital Editions about the digital rights (one needs to have Digital Editions installed prior to downloading the book). Or maybe even some restrictions on the company's computer was to blame. Still, I'm not buying anything that requires additional software anymore. –  Arjan Sep 12 '09 at 8:07

Even if you can do this, you can't stop user from makeing screenshot and then printing an image or something like that. If user can see data, you can not stop him from makeing a copy, so my advice is "don't even try". Make a noticeable warning that pdf should be printed only once and leave it like that, because if user want's to print it two times he/she will find the way.

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I wish this was an option. This is something for a client, we don't make the requirements. We're aware the whole concept has fundamental flaws, but we basically want to make it as hard as possible for average Joe to print off more than 1. –  pauldunlop Sep 7 '09 at 16:07
    
If you are a consultant, part of your job is talking your client out of silly ideas. ;-) IMHO, if you end up implementing any kind of restriction that has a easy workaround (e.g. a photocopy machine), it will only end up irritating end-users to the possible point of product abandonment. –  Chris W. Rea Sep 7 '09 at 19:16
    
I'm not the consultant on this job, just the developer sitting in on an initial meeting. Have already advised our sales guy this seems like a lost cause. Problem is, a competitor has produced a number of solutions, through ActiveX controls, and dedicated apps you have to install to handle all this, we're just trying to find a more elegant solution. Not worth it if you ask me, but thanks for your advice. –  pauldunlop Sep 8 '09 at 8:54

We've done things like this with watermarks. The PDF always has a watermark except for some given "event" that will allow the user to print (like payment in our situation). Then we re-render the PDF without the watermark.

Not exactly what you're after, but perhaps the watermark notion could be helpful?

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Interesting idea, hadn't considered something like watermarking. The issue will be, though, that on that first print, un-watermarked, we won't be able to stop them printing 10 copies, etc. Hence I was wondering if the PDF spec contained anything like this? –  pauldunlop Sep 7 '09 at 16:09
    
Not that I'm aware of. Alex has a good link, but I don't think it handles number of copies -- that's the local printer driver's job, right? –  Chris_K Sep 7 '09 at 16:17
    
Yeah, it is. Basically, we need to somehow by-pass the local printer dialog, and make use of something else where we have control over what options the user gets to see. Strongly suspect this won't be possible, but am researching it anyway just to be thorough. –  pauldunlop Sep 7 '09 at 16:19
    
Hmm, so you always render the PDFs as locked for printing. Then, the only way they can be printed is to be sent/passed to another application of yours that can toggle the lock and keep track of filenames and if they've been printed before. Yikes! –  Chris_K Sep 7 '09 at 16:24
    
Sounds too complicated to work on anything except a specific version of Windows/Acrobat. I had a PDF sent to me (bought) that was restricted from printing ever. I didn't know when I bought it, unfortunately, and wanted to print out a page of code to go over at a desk. The vendor would not let me remove the restriction, but I found numerous places online that let me remove the block. If you implement this, it is more likely the client will lose business than keep business in this case. –  Joshua Nurczyk Sep 7 '09 at 22:09

Try this tutorial from Adobe:

You can prevent users from print a PDF form. You can specify whether the form can be printed, printed with minimal resolution, or printed with a high resolution output.

1.Select File > Form Properties.

2.Click the PDF Security tab.

3.In the Permissions area, select Use A Password To Restrict Printing And Editing Of The Document And Its Security Settings.

4.In the Printing Allowed list, select one of the following options:

•None

•Low Resolution (150 dpi)

•High Resolution

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Useful link, but doesn't allow me to restrict the number of print copies to just one, as far as I can tell? –  pauldunlop Sep 7 '09 at 16:20
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It's not possible to only print once. And even if it were, think about it; I give 3 copies of the document away (or I only give one, but then someone makes more). Each document would then be printable once. The pdf does not contain info on how many times it was printed. And another thing; if I use CutePDF (or similar) and print the initial document as PDF, then I can bypass all restricions because the new document doesn't contain the initial metadata. –  alex Sep 7 '09 at 16:36
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Trust me, either choose another way of printing, that doesn't involve PDFs, or just make the customer drop the print limit. It's not technically possible. There are always way around, especially if there's a loophole such as being printable once. –  alex Sep 7 '09 at 16:39

I cannot find any Adobe PDF feature that counts the number of times the document is printed. I only find disabling all printing. This makes sense when taken with the following in view:

If I were the PDF pirate you fear, and you created this elusive print-once PDF, I would merely send it to my printer, once.

Whereupon:

On a Mac I would choose to preview the printout before clicking "print", and save the PDF preview it generates.

On a PC I would ask the printer driver to also spool the job to a file.

Or on either I would choose a print-to-file driver, many of which are free.

And if none of these above options were available to me, I could ask my printer driver for many models to also spool the PostScript to disk first, or in dire cases, sniff the network traffic to the printer off of the network. It's generally not authenticated or encrypted. The PostScript could even be distilled back to PDF if need be.

Edit:
Even with the java printing applet that Pitney-Bowes uses to print postage, which seems to disable the preview option I've saved the resulting print job for reprinting. But I don't use this option any more because it simply cannot seem to print correctly on any kind of paper size, it's always printing the bar code off the margins of the page, even when I play it straight with the print-once intent.

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Yeah, I'd thought about those PDF, spool to file problems as well. Hence, ideally, something is needed that totally by-passes the inbuilt OS printing facilities. Which on OS X specifically, I'm not sure is possible. Fun fun! –  pauldunlop Sep 7 '09 at 16:50

I'd say this is not only impossible technically speaking, but also, impractical.

What's stopping the user from photocopying the document right after printing it ?

What is it that you're trying to accomplish by this, apart from gather a few novel suggestions ?

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The scenario we have is related to voucher/coupon printing. Basically, the client needs to ensure a user only has one copy of the voucher. Having validation at redemption (in store) isn't an option, so it needs to be at the time of printing the voucher. Essentially though, what you said about photocopying, etc, is entirely true. The idea is flawed, but I'm just exhausting all possible avenues before saying so :-) –  pauldunlop Sep 7 '09 at 16:48
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@Chops - well, couldn't you put some kind of serial number on it ? To differentiate between them ? And then destroy them as they are used, after checking the serial so one with the same number cannot be used twice ? –  ldigas Sep 7 '09 at 18:41
    
We could, and in fact, the clients currently implementation does this, but because they're providing vouchers for multiple clients, they don't have the serial check at purchase in the retailer, so in theory a user could print lots of vouchers and redeem them, and the retailer wouldn't be able to tell. –  pauldunlop Sep 8 '09 at 8:49

"Hmm", (as Deep Thought said), "Tricky"

How about distributing access to a web site with a simple log-in requirement that contains the voucher. Print the voucher from the webpage.

Set the site up so that the user can log-in only once.

You might be able to set the site up so that the voucher does NOT show on the web page - though I do not know how to do this. If you can do this, you prevent the user from downloading and making multiple prints.

If something goes wrong with the log-in, provide a legitimate, but not too easy, way to get another log-in.

Of course, you could always mail a physical voucher to the recipient.

If you are concerned about photocopies, there are ways to prevent that - look a medical prescriptions that use "secure paper" for an example.

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Any kind of thin enough paper will do ... for example, the red copying paper engineers used is a good option for this. –  ldigas Sep 7 '09 at 19:17
    
Most anti-copying mechanisms use some hard to see hight-dpi pattern/raster that shows interference when scanned by a photocopier. For home-printed vouchers I guess such pattern might yield unexpected results, due to the quality of the printers, which might (or will?) not be able to successfully print those patterns. Would not be too nice if the original printed with the pattern visible... And @ldigas: instead of sending empty sheets of paper to the customer's home address, I guess one could also send the voucher itself. Problem solved. ;-) –  Arjan Sep 12 '09 at 9:19

If you can print once, you can print an infinite number of times.

Consider a network printer: the raw data to be printed has to be sent to a remote embedded device, which your program would have no way of restricting, even if it somehow assumed ownership of the user's entire machine (which would already be considered extremly offensive; see the Sony rootkit scandal for the kind of reaction to expect).

How could you tell the device the user's machine is talking to is a real HP LaserJet, instead of something which pretends to be one (or, even simpler, pretends to be a remote spooler), but which saves the raw PCL/PS/whatever instead of printing it? Since that data is all that is needed to print the job, one would just have to replay it several times to a real printer to get several copies. You could also use a sniffer (as @dlamblin mentioned) and save the trouble of emulating the printer.

You could think of forbidding network printers, but having only network printers in an office (not simple printers attached to a general-purpose PC, but large printers plugged directly into the Ethernet switch) is not that uncommon. Because of that, several of your users (how many would depend heavily on the target demographic) would not be able to print, which is not good PR.

And even USB is not immune (though it would need more technical knowledge and perhaps special hardware); there exist USB sniffers. And even without them, a usb printer "gadget driver" on an embedded Linux device could be enough (note, however, that as of this writing I know of no usb printer gadget driver for Linux).

This is all assuming the program has somehow managed to obtain complete control of the user's machine. As the several failed attempts at copy protection show, this is easier said than done. How can you know that the printer driver you are using is just an uncommon version of the printer driver for a popular brand of printers, and not a hacked version to save the stream to the disk? How can you know there is no driver somewhere in the printing stack logging all the USB transactions to disk? And how can you differentiate a normal user of virtual machines from someone using them to intercept the communication with the USB devices?


All that said, you do not need to go that far. Most people, even if they have the technical know-how, will not attempt to bypass even the weakest attempts at preventing duplicate printing you make. In fact, I would not be surprised if most users would voluntarily not print more than once if told the file must be printed only once (but then there would be more cases of people accidentally printing twice). So, make a simple program which prints once and then erases the original data. Warn the user that the data will be erased after being printed once. And accept that some people will print more times than you allowed, and that some people will print less times than you allowed (power glitches, defective printers, misconfigured systems, or the dreaded PC LOAD LETTER can all cause the printing to fail). Be prepared for that.

For people who print more times than allowed, just accept the losses, the same way a physical shop has to accept that a fraction of its stock will be accidentally damaged or lost in some way. Have some way of finding the biggest abusers and dealing with them (the legal system seems to be a popular choice).

For people who print less times than allowed, something like phone support where the user can request a new copy would be an option (it works for Microsoft, right?). Of course, some people will abuse this, but see the previous paragraph.

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I know that many event tickets delivered as PDF don't worry very much about this. Instead, they assert very strongly that the venue will be scanning the barcodes, and that only the first copy of a given ticket will be allowed through the door. They also have a tendency to print the purchaser's name on the ticket, making it possible to ask for ID at the door as well.

Fundamentally, I don't think it is possible to make a print-once PDF file. And even if it was, I'd suspect that the customer relations cost from print problems and bad word-of-mouth would cost more that its worth.

TurboTax (a US Federal and State income tax preparation tool for the non-US readers) tried something similar a couple of years ago. They decided that it must only be possible to install the program once with printing enabled, which was enforced by an activation code from their server. It turns out that a significant number of their customers were in the habit of doing taxes at home, but installing a temporary copy at their office to take advantage of the available office printers. There was also a loud complaint from people concerned that about being able to reinstall that year's software later to fix the return if an audit revealed an issue.

The complaints were loud enough that no subsequent version has had these restrictions.

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The scenario we have is related to voucher/coupon printing. Basically, the client needs to ensure a user only has one copy of the voucher. Having validation at redemption (in store) isn't an option, so it needs to be at the time of printing the voucher.

Did you consider personalising the prints, requiring some id (and maybe some signature) when using the print in a store, and leave it up to the sales agreement that only a single copy is to be used? Then you'd need some final processing (at some later time), to register what vouchers have been used multiple times, and (threaten to) bill the customer for that... (This could even be an additional thing, next to trying to limit the number of prints.)

Note that not everyone has a quality printer. Some scans or photocopies may look better than some original printouts.

Also, like @RBerteig already noted, some customers may not even have a printer at all, or may have run out of ink. How would they print at some neighbour or at work when your solution needs additional software, like (the horrible, in my opinion) Adobe Digital Editions? Extending on that: what will the electronic voucher be like? I think you'll be implementing some online validation at redemption in the next release, for those showing you some barcode on their smartphone rather than some paper voucher.

We're aware the whole concept has fundamental flaws, but we basically want to make it as hard as possible for average Joe to print off more than 1.
[..]
Problem is, a competitor has produced a number of solutions, through ActiveX controls, and dedicated apps you have to install to handle all this, we're just trying to find a more elegant solution.

Ok, it's clear that you will eventually implement some solution that will not be very secure. I guess you'll have some written statement for the client about the risks. I suggest that in that written statement you also show the customer how easily that competitor's solution can be used to print multiple copies.

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The idea that a software program can control that a user only prints something once is a flawed idea. Think about paper jam - just because some application or operating system successfully have sent of a printing job to the printer does not guarantie that the user gets a copy. So what should the user do then?

Or what about the printer being configured to print X copies of each sheet? What about scanners or photo copiers?

And finally, while there obviously is no benefits from the user's point of view for such an anti-feature, I have absolutely no idea what the benefit should be for your company. Could you please explain what excatly what the benefit for doing such a thing is?

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I am not a techie but it might be worth your while to check out the "Globe and Mail" (Canada) website. This is a newspaper which charges for the number of print copies -anything from one to hundred. You may be able to adapt whatever they have done to your own problem. The reason I am looking at this site is because i am about to launch a website and want to protect my content. Good Luck

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unless they somehow open sourced their DRM solution, this isn't likely to be of all that much use... and open sourcing DRM, is a little unlikely –  Journeyman Geek Dec 8 '11 at 9:47

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