Right-click on a PDF, then in Safeguard Secure PDF Writer, choose the protection options:
Ebook Encryption and E-Book DRM
Ebook encryption is the process of applying encryption technology to an ebook to render it unusable to anyone without a key to decrypt it.
However, once someone has the decryption key they have complete control over the ebook. So you must apply additional controls to stop users sharing ebooks and keys with others, lock use to authorized devices only, and stop editing, copying and printing.
When encrypting an ebook you need to think about usability. For one thing, while encrypting the ebook may seem a straightforward process you have to consider how you are going to deliver decyryption keys to users, what software is going to decrypt the ebook so that it can actually be read, and how you are going to control use (stopping sharing, printing, etc.) once the book is decrypted. As a result, ebook encryption is not quite so straightforward.
You could use any encryption software to encrypt an ebook such as the well recognized encryption/decryption standard OpenPGP. However, you need to be aware of the fact that you do not have any digital rights management (DRM) controls as a result of using this type of encryption and therefore cannot control use of your ebooks once an ebook is decrypted. The OpenPGP encryption approach is simply used as a means of ensuring that only those authorized are able to decrypt information. It does not impose any controls on what can be done with the ebook once it is decrypted.
So ebook encryption is not a method for controlling the use and distribution of ebooks, although it may be appropriate as a technique for transferring a draft ebook from the author to an editor or proof reader and back again. Encryption protects information from access by anyone who is not authorized, but allows the authorized to do anything they like with the information – it has not concept of controls that note when an ebook is copied, printed or otherwise used.
To control what an authorized user can do with an encrypted ebook you need to use DRM and licensing controls. These enable an ebook publisher to:
A good ebook DRM system will provide all of these features and ensure that when ebooks are decrypted no temporary files are created (so content is only ever available in memory and there are no unprotected files available to copy).
Ebook DRM systems from Amazon and Adobe provide limited controls and have have been broken (i.e. the ebook protection can be removed). Locklizard use the PDF format which renders in the same manner across multiple devices (so your ebooks always look the same), and don’t rely on the Adobe Security Handler for protection – see PDF Security Issues, PDF & Ebook Weak Implementations as to why.
In summary, ebook encryption is a very valuable tool for a limited number of situations that are themselves critical. Ebook encryption is, however, essential as part of an overall strategy for providing digital rights management controls. Without ebook encryption preventing recipients from being able to just copy the ebook any number of times and give it to any number of people is not possible.