Secure File Contents & Secure Information

Secure file contents & secure information with a DRM tool

A DRM tool is a computer program for adding digital rights management controls to a file and/or to the content(s) of a file.  In the most general sense this is used to secure file contents by controlling the current and subsequent use of the secure information in the file.

There are two basic classes of files that are controlled: those intended to be machine processed, and those for humans to read.

At first glance you might think that producing a DRM tool that would secure file contents for machine processable information would be easy, but actually it turns out to be a difficult way to secure information.  That is because it is technically difficult to apply controls to each piece of information in a file such that the control persists with the information so that every subsequent program that processes it must honor the controls.  So although it would be nice to be able to secure information for computer processing it turns out not to be.

By comparison, controlling human readable files is easier.  A DRM tool to secure file contents works by stopping a user from giving the secure information to other people.  This means stopping them from saving the secure file in a form that does not have the controls, and preventing them from creating forms of the secure file that could be used to readily re-create an unprotected file.

Thus a DRM tool to secure file contents is acting to prevent unauthorised use by the actual user.  This is because secure information may have different properties – one item of information may need to be secured while other items are not important.  But a DRM tool cannot be that sensitive.  It looks to secure file contents at the file level, rather than all or nothing process.  It also treats the users as being in groups or categories, each category having the same rights.  This removes the complexities of trying to secure information at a very granular level.  So a DRM tool can be very effective to secure file contents overall, but is not currently suitable to secure information at a granular level.

Often a DRM tool is used to link the identity of the user to the secure file contents (by methods such as hiding their identity in music or streaming video) again operating at the overall secure file contents level.  This is also the case for controlling satellite television broadcasts through decoders.  Obviously it would be too complicated to attempt to secure information within a digital stream, so a DRM tool does not attempt to do this.