Some book formats, such as Adobe PDF, allow you to use one method for a secure ebook, because you are only dealing with one type of format of presentation (generally static files without animation).
But if your digital book uses multiple formats, such as the multiplicity of video formats (mpg, mpeg, wmv, avi, mov, 3gp, mp4 and so on) it may prove difficult to find a simple way of getting you secure digital book, especially when there are so many possible players that might be used.
Many companies migrated their audio and video formats to Adobe flash (FLV and SWF files) because over 97% of all browsers can have the free flash player installed via a plugin. So it was seen as a convenient solution that was widely supported. However, flash is not without its problems, and security is definitely one of them (it launches external files that launch a new process with access to its own memory, and hackers have successfully and repeatedly used this approach to gain access to the operating system). The future for flash now looks bleak – Chrome already has the flash player plugin disabled by default – but it is still supported by the industry since some older browsers do not support HTML5.
One approach to resolving how you obtain a secure ebook is to limit the actual number of presentation formats that you wish to support. This is not likely to be a simple matter, especially if you are using existing work that has been created following a particular standard. One current answer would be to convert whatever format has been used to produce the original material into a single common format. Although not a specific recommendation HTML5 is a good format to use since it supports both audio and video. It is a common format for both the Mac and Windows platforms, since it is supported by all the common browsers – so users don’t need to install any insecure plugins to view video files.
But even if you have converted all your audio and video works to a single format, you need to be confident that the other static formats – text, pictures and so on, can be secured. So you need to think about stopping screen grabbing and printing, preventing editing and dynamically watermarking content to identify users. So to provide secure ebooks requires a system that can handle many formats, and provide security against copying and printing where materials are multimedia, pictures and text.
PDF ebook security
If your ebook is mainly static (so you have links to externally hosted audio and video files rather than them being embedded within the document) then converting to PDF format is often seen as a wise choice. Why? Because PDF is the most widely supported document format worldwide and there are numerous applications that will convert ebooks in most formats to PDF files. It reliably produces the same document appearance in different avoiding the need for customization.
Adobe and other PDF creator software provide a basic level of security for free with PDF password protection. However it is not very secure because even if a strong password is used to the protect the PDF file, passwords can be shared with others which defeats the objective when selling ebooks and trying to prevent ebook piracy. Also, PDF restrictions (stopping printing, editing, etc.) can be removed in seconds with freely available password recovery tools. So clearly PDF password protection is not a way forward for securing ebooks.
A more secure approach is to use public key technology which enables keys to be transparently and securely relayed to a user’s device – so there are no keys (passwords) for users to enter or that can be readily attacked and therefore broken by applications. This is the approach Locklizard use in our PDF DRM software delivering licensing, DRM, and operating system controls to authorize users and control document use.