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    How to Lock and Protect a PDF File

    If you have sensitive information stored in PDF format, then you likely already understand the need to keep it safe. For most corporate entities, keeping sensitive documents confidential is crucial as a document in the wrong hands could spell doom for the whole organization. But, as the U.S. government could tell you, keeping documents safe is not always easy; they even have the first-hand experience with the widely publicized Snowden situation. So, is there a way to protect PDF documents?

    A document DRM system may be your best chance at pulling it off.  Below, we discuss the features available in a typical document DRM system that could help you protect your files.


    Locking Documents to a Device:

    The main reason why documents are leaked is that the users can transfer them to other devices and therefore share them with non-authorized users. So, if you could prevent your documents from being transferred to another device, they would be more secure.

    DRM systems make the transferred document unusable on another device. In other words, a user may send out copies of your document, but none of them will show the contents because the keys that are needed to decrypt it are locked to the specific user’s device.  The decryption keys are not exposed to the user (so there are no passwords to enter) and if a keystore (an encrypted file where keys are securely stored) is sent along with the document, the key will not be made available as the keystore only works on authorized devices.  The document will, therefore, fail to open.



    Stop Document Copying:

    If users cannot send a document in its original state, they are bound to try another method. Copying and pasting the content is one such method as they can create another copy. Users could also try the “save as” option, whereby they can save a copy of the file in a different format without the original document’s security input.

    Document DRM systems already have measures in place to prevent the use of such functions or to ensure they are not made available, to begin with. It is, therefore, impossible to use such traditional methods of copy and pasting to make a duplicate.


    Stop Printing of Documents:

    A document thief could print a copy, scan it, and then freely share the newly scanned PDF. While this is undoubtedly creative, most DRMs have this covered as the default setting is to disallow printing. However, in reality, there may be situations where you need to allow printing. Document DRM systems enable you to do this while regulating the number of copies that can be printed. In this way, you can better account for the hard copies given out.

    Worth noting is that, with document DRM, you can include a dynamic watermark within the document. A dynamic watermark lets you insert variables into a PDF file when it is protected and these variables are replaced with user and system data when the PDF document is displayed and/or printed. This means that you can know exactly who made which hard copy. And, if your document were to find its way into the hands of unauthorized users, you will be able to determine who the source of the leak was. You can then take legal action against the guilty party. Knowing this, most users will think twice before sharing your documents.


    Prevent Editing:

    If you allow the editing of your content, authorized parties may decide to add irrelevant information or remove something crucial. Yet, you probably want the integrity of your document to remain intact. So, it is imperative that you disable editing/modifying of PDFs.  A DRM system will prevent users editing and modifying the content so that content cannot be copied and pasted into other applications.


    Stop Screenshots:

    Most people are familiar with taking screenshots in which all the information on a screen is recorded in the form of an image. Once you allow a screenshot to be taken, there is a copy of your document in image format.

    Document DRM systems use technology that prevents people from taking screenshots, whether they try to do so by using the default desktop screenshot or by using third-party apps. This ensures that a quick and simple method of document copying is automatically prevented.


    Log Use:

    Being able to see how your documents are being used – when and where they are viewed and printed and by whom can be invaluable.  It can help identify unusual behaviour and identify leaks.  This could be used to great effect as a deterrent if users know that their actions are being monitored.


    Expiry and revocation:

    Lastly, a document DRM system should be capable of enabling you to set documents to automatically expire after a certain time frame and have the ability to revoke documents at any time regardless of their location.

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    Ecbert Malcom
    Ecbert Malcom
    I am a resident author at Broodle.
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