FAQ: The FileOpen PDF Plug-In for Adobe Reader/Acrobat

Who is FileOpen Systems?

FileOpen Systems is a software development company based in Santa Cruz, California. We are an Adobe Systems Security Partner. For more information see the About FileOpen page..

What does the FileOpen PDF Plug-in do?

This plug-in is required to open PDF files encrypted by FileOpen rights management software, and is authorized by Adobe Systems to load in Adobe Acrobat and the free Adobe Reader. The plug-in manages the open and print commands in the Adobe Reader according to the access controls set by the publisher. Any access controls on the encrypted files have been placed there at the discretion of the document publisher. The plug-in alone will not grant access to encrypted files; you must follow the publishers' instructions for obtaining access.

What does the FileOpen software not do?

The plug-in alone will not grant access to encrypted files; you must follow the publishers' instructions for obtaining access. Please contact the document publisher, not FileOpen Systems, for permission or any technical support required.

FileOpen Systems does not charge for the use of the plug-in or monitor its distribution. Nor does it derive any revenue from advertising or the sale of information of any type, especially not information about users of our software. For more detail please see our privacy policy.

What, exactly, is the FileOpen PDF plug-in?

The plug-in package consists of the FileOpen.api Acrobat/Adobe Reader plug-in, and an optional companion plug-in, fowp4kbd.api. The main plug-in, FileOpen.api, must be installed to open encrypted documents. The companion, fowp4kbd.api, which restricts the taking of screenshots, is optional though some publishers may refuse to grant permission to open files if this plug-in is not installed.

In some instances, under Windows, the installer will also deposit a program in the system tray called FileOpen Certification Manager. This program manages the transition in and out of an Adobe viewer state called Certified Mode, and should only be installed on systems that have a copy of Acrobat/Reader 7 or lower and have installed at least one Adobe eBook; you can delete this program by clicking on its taskbar appearance and selecting Uninstall.

Where does the FileOpen software get installed?

Adobe Acrobat loads plug-ins at application startup from a pre-defined directory, so the FileOpen.api plug-in has to be copied to that directory. By default, on Windows, the directory is:


On Macintosh the plug-in is difficult to find, as it becomes part of the "packaged" Acrobat/Reader application, but you can find a link to it by selecting the launch icon for the Adobe viewer and clicking Apple+I then finding the drop down for Plug-ins. From here you should FileOpen<ver>.acroplugin. You can also add/delete the plug-in from this menu.

Locations on Linux may be obtained by searching for "FileOpen".

How does the FileOpen software get installed?

FileOpen Systems provides installer programs that detect the location of the installed copy of Acrobat and copy the plug-in(s) to that location. We provide these installers to our customers, who are free to distribute them to end users. We also maintain https://plugin.fileopen.com/ - an installer on our website to which publishers may refer their users.

What does the Web-based installer do?

The installer on FileOpen's website attempts to provide a simple and seamless install via the browser. However, it works differently for different operating systems and browsers. The default automatic installer uses a Java "conveyor" to download and execute the installer. Users of IE without Java but with security settings that allow signed ActiveX controls to be loaded - the default setting - may see an ActiveX installer. The Java and ActiveX programs are only for convenience and the end result is the same regardless of whether the plug-in is installed via the web, by a downloaded copy of the installer, or manually.

Which privileges are required for the install?

Typically, Windows users must have PowerUser (or Administrator) privileges to run the installer, though all that is really required is write-permission to the Acrobat plug-ins folder.

What if I don't want to run the installer?

The operation of the plug-in is identical whether it is placed into the Acrobat plug-ins folder location by the installer or via a manual operation. If you don't want to run the .exe or Java or ActiveX installer, you can get the plug-in from here and copy it to the location given above.

Do you provide an installer for MSI?

An .msi installer is available from here, along with instructions for signing that install for SMS delivery.

Once installed, when does the plug-in load?

FileOpen.api is loaded by Acrobat or Adobe Reader at application startup, i.e. when you load Acrobat/Reader, it loads the plug-in. However, the plug-in is invoked only when a document calls for it (i.e. if you do not attempt to open any encrypted content, the FileOpen.api is inactive). In short, the plug-in does nothing unless a document encrypted by a publisher using the system is open.

Once installed, what does the plug-in actually do?

When a user attempts to open a document encrypted by a publisher using FileOpen's software, the client reads information from the encrypted document and performs the following steps:

  1. Obtains information about the document being opened and the publisher's authentication requirements, from the document. Depending on those publisher requirements, the plug-in then retrieves one or more of the following authentication tokens from the local machine context.
    1. A cookie from the user's login to the publisher's server.
    2. A username and password from a dialog presented to the user.
    3. A MachineID from the local context.
  2. Makes a request over http/https to the publisher's server, passing the document identifier, authentication token, and some data about the context in which the document is being opened.
  3. Retrieves a response from the publisher's server either granting or denying the user permission to open the document.
  4. Manages the use of that document according to the instructions given by the publisher's server.

Which operating systems are supported?

The FileOpen Client will work on Windows 7 or later, Mac OSX 10.9 or above, iOS, Android and Linux.

Where can I get more information on installing/removing the FileOpen software?

For other questions please contact the publisher of the document in question or via https://www.fileopen.com/contact-us/.
FileOpen Systems has been a licensed Adobe Security Partner since 1997.