What is DRM ?
DRM is a form of copyright protection that limits what you can do with computer files. The software which controls how you can read, copy or sometimes printable the ebook you have downloaded.
Digital rights management (DRM) is a term for access control technologies that are used by hardware manufacturers, publishers,
copyright holders and individuals to limit the use of digital content and devices.
DRM technologies attempt to control use of digital media by preventing access, copying or conversion to other formats by end users.
Digital Rights Management Techniques include:
Restrictive Licensing Agreements: The access to digital materials, copyright and public domain are controlled. Some restrictive licenses are imposed on consumers as a condition of entering a website or when downloading software.
Encryption, Scrambling of expressive material, and embedding of a tag: This technology is designed to control access and reproduction of online information.
This includes backup copies for personal use.
DRM-Free means no 'digital rights management,' which means no special software needed. You can read DRM-Free PDFs on any device you can read any PDF file on.