This article will overview PDF copy protection and the available options. A couple of important points worth making before explaining some options available to copy protect a PDF file.
In order to copy protect a file something must be done to the file to maintain control of it. “Something” means changing the file somehow to make it secure. Here is an analogous example; anyone can drive a car, but you need a key to start the car. The “key” makes your car secure.
Staying with the car analogy, you have options for transportation. You can own a car and give the key to whom ever you want to drive it, or you can summon an Uber and have someone drive you around. Copy protection is more like the Uber, than the personal car.
To copy protect a PDF file, generally the goal is for anyone to see the file, just not save the file, print the file, share it, stream it or screen capture pages from the file. Just like the ride-share concept, Uber wants everyone to have access to those cars, but not let everyone drive those cars.
Coming back to the copy protection problem and our earlier comment about something must change with the file, it is important to understand encryption is different than copy protection. Encryption is a technology where the file is mixed up into random pieces and the owner assigns a password to those pieces. When the correct password is entered the PDF comes back together and readable.
The issue with encryption is once the password is entered correctly anyone can do anythign they wish with the file. It’s like keeping the honest people honest. The user can do anything they wish with the file; print, share, save, screen capture, etc. This is like owning the car and the key to start it. Of course you will only loan the car to people you trust. See the problem?
Copy protection does not use a password, yet anyone can see the file. Yes there is encryption, but the method in how the encryption is applied and used is a bit different. Like the Uber car, the driver has they key and will drive you to any location requested.
The idea behind copy protection is the PDF being viewed by anyone, but nothing can be done with the file. When people are searching for PDF copy protection, this is the solution most likely sought after.
PDF or Portable Document Format is an open standard. What this means is the document format was designed to be used in just about any document reader program. The goal for the PDF specification was to make the format as universal as possible. For this reason, it is a bit more difficult than one would think to copy protect a PDF file.
Windows comes pre-installed with Adobe Reader. In addition, Windows has embedded Adobe API code to read PDF files. Even if Adobe
Reader was not installed on your computer, or uninstalled, the underlying code is still there to open a PDF. In additional to Adobe Reader (#1 PDF reader in the market) there are dozens of additional PDF reader programs. Again, the goal for all these readers is to open and read a portable document file.
Adobe copy protection solutions are very well known for being cracked. If you Google “Adobe copy protection crack” you will find pages of ways the Adobe security features are compromised. Here and here are two examples of Google search results with web pages dedicated to hacking.
The fundamental problem with copy protection are the lack of controls when viewing a PDF. Meaning a PDF content owner (you) does not have the control over Adobe Reader, or other programs, to stop the user (your client/customer/student) from printing, screen grabbing, sharing and saving.
The idea behind a PDF copy protection solution is a framework where the PDF can be opened and viewed, while you (the content owner) maintains control of the document.
Of course Adobe Reader, FoxIt Reader and others, will not provide the tools to block a user from printing or saving from within their program. In contrast, we need a “reader” or “viewer” with controls to block those functions.
With this in mind, it is difficult to provide a reader with these security functions. Most users who receive a PDF do not want to download and install another program just to read a PDF file. The ease and beauty of a PDF gets lost in that process. No longer is the PDF a portable document format. In addition, a software program that can be downloaded to view a PDF can also be downloaded by a hacker to be reverse engineered. There needs to be something more than just a secure reader/viewer to control the PDF.
The most secure way to copy protect a PDF file is to associate it with something physical. There are some software (only) solutions, but those are not as secure as a solution with something physical.
In our research to this problem we found a product called the Copy Secure flash drive by Nexcopy. The Copy Secure solution is a USB flash drive which is a physical device that provides copy protection to PDF files without installing a program to see the file. In reality the solution is a copy protected device, not a copy protected file. This is true, because the physical device is the physical key to control viewing of the document.
The secure PDF reader on the Copy Secure drive is coded and locked to the device itself. So even if a hacker downloads the viewer application which runs directly from the flash drive (no installation required) they still won’t have the tools needed to unlock the PDF and control it.
The Copy Secure drive works in both Mac and Windows computers. The viewer application which automatically launches from the USB makes it a seamless experience to view the PDF. The PDF remains a portable document format.
From our testing, the viewer does not allow for printing. Does not allow for saving, screen capture or sharing of any kind. With this solution, the PDF follows the USB drive and may be accessed from any computer. No need to download a secure viewer to each computer the PDF will be used on, simply insert the Copy Secure USB drive and access the file. Everything runs directly off the flash drive.
In the event you need additional digital rights management there are additional features one can use to control the PDF. The Copy Secure solution has a time expiration feature for the PDF. This restricts the client/customer/student from accessing the PDF after a specific date.
If the PDF has sensitive data which the PDF does not want anyone to see, the Copy Secure solution gives the option to assign a
password before any PDF is viewed. Meaning, there are now two layers of protection the content owner has: First, the client/customer/student must enter the correct password before the PDF is displayed. Second, once the PDF is displayed the file is still copy protected, so even the most trusted user cannot print or save the PDF.
While doing research on how to copy protect a PDF file, we came across several other products worth mentioning.
Adobe – They offer a solution but after a quick Google search, we determined there are too many hacks to consider this as a viable solution.
PDF2GO – This is a great on-line solution but we found the price to be very expensive for medium and high quantity applications. This solution might be best for a one-off need.
LockLizard – This solution also falls into the pricey category for medium and large sized business models.
In conclusion: The idea of a physical device connected to the security of the PDF is very inviting. If the PDF content owner has a business model where the intellectual property of the PDF content is directly tied to revenue, we believe the Nexcopy solution is best. Unfortunately with Adobe being such a large company and therefore a target of hackers, their security solutions have been compromised over the years. The other two solutions, which are “software only” such as PDF2GO and LockLizard are well suited for one-off or very small needs, but just a bit pricey.