Digital Rights Management is a method of protecting content so that only valid and licensed owners of the content can access the content. DRM (digital rights management) is one of the leading ways to protect music, video and documents on the internet. In fact the concept of digital rights management is very simple and has constantly evolved to protect content. To illustrate how digital rights management works lets take an example, lets say I have written an e-book and want to sell it online, the first thing I need to do is protect my hard work so that no one can copy and distribute it freely.



I can upload an e-book online and ensure that only people who pay for the book can download it, but this does not stop anyone from making copies and distributing it freely. A common work around this problem is to password protect the e-book. So after a customer pays for the book and downloads it, he then receives a mail with the password to open the e-book he has just downloaded. Unfortunately that is no protection at all; the user who has just downloaded the file can actually copy the file and attach the password with each copy he makes. So in essence password protecting a file is no good.

So then what else can I do to protect my e-book? This is where DRM came up with a new method of protecting documents and other files. Whenever a user downloads my e-book, in the background he will also download a file that will contain the password to my e-book in encrypted format. The file downloaded in the background is called a voucher or certificate, and every time a user tries to open my e-book, the e-book will look for the voucher; if the voucher is not present on the computer the e-book will not open assuming that the copy of my e-book is illegal.

So does using vouchers make DRM more effective? Partly, smart users can make out which file is being accessed when they try to open the e-book, and just like the password they can actually send the voucher with the e-book as well. The only thing in favour of vouchers is that a majority of users are not savvy enough to figure out which files are being accessed whenever the e-book is accessed. With the number of internet and computer users increasing, the number of computer savvy users has increased, so my e-book is only partially protected.

So then what is the latest and the most effective in DRM? Well the idea is to tie my e-book into something that cannot be transferred from one computer to another, the hardware of the computer. DRM protection today actually generates a file that uses the hardware on the computer to generate a unique ID. This file uses the CPU id or other distinctive hardware features to protect the e-book. So even if the e-book and the voucher file are sent to another user, obviously the hardware will not match and the e-book will not open on any other computer.

Another popular way of using DRM is associating a file with the IP address of a computer, even after a user changes his hardware his IP address is assigned from the ISP and therefore any hardware changes will not affect the IP address or DRM of the file on the computer. The problem of using IP addresses in DRM is that a user will always have to be online when he accesses the file, as the file will connect to a remote server to check the file and IP association. Also a network of 1000 computers using the same internet connection will have the same IP address, so the file maybe protected against mass distribution but it will be freely accessible over the entire network. A solution to this is to use a combination of IP and hardware protection in DRM.