How CD/DVD/Blu-Ray Copy Protection Software Works [Technology Explained]
But opinions aside, you may be wondering how copy protection software works. The answer to that question varies depends from one disc to the next, but there are a number of general categories into which copy protection software can be grouped.
Region Locked Copy Protection
Optical media, particularly in the form of DVDs and Blu-Ray discs, are often “region locked”. This means that they contain a form of copy protection that prevents a disc from playing if it is inserted into a player that contains a different region code than the disc.
There are some “region-free” players, and in the case of players such as computers, it is sometimes possible to change the region code of your optical drive. Players such as PowerDVD will ask you to change your region if you insert a region locked DVD, and players such as VLC Player ignore region locks completely (if the firmware of your optical drive allows it).
An incredibly popular form of copy protection, disc encryption protects content by encrypting it using one of a number of set encryption keys. The encryption can only be broken (in theory) if a valid key is used to decrypt the content, making it available for viewing. If a valid key isn’t used the content will be unplayable or scrambled. This also prevents users from copying a disc or burning it to another storage device such as a hard drive.
Encryption is a running game, however. The encryption keys used can be compromised, often through reverse engineering. Encryption can also become vulnerable to brute-force attacks as computing power increases. Agreed encryption standards often don’t change as quickly as computer hardware progresses. The creation of software capable of bypassing copy protection is illegal in many parts of the world, but there are still free decryption programs available.
Registration Keys and Online Product Activation
Computer software is very difficult to protect against piracy because of its nature; the software must be installed on a computer in order to function, and once installed it can be copied or altered.
Registration keys used to be the standard method of protecting software, either on disc or downloaded, but such keys are also vulnerable to being compromised. The keys are usually generated using an algorithm, and that algorithm can be reversed-engineered or otherwise compromised. This is why “key generators” are capable of creating a valid registration key for some programs.
As a result, companies such as Microsoft have moved towards online production activation. When you buy a Microsoft Windows 7 disc, for example, you receive a key in the box. This key is activated through an online server that not only checks that the key is valid but also checks that the key hasn’t been used before. If the key has been used before, the server tries to determine if the key is being used by the original buyer.
This sort of activation remains controversial. Some forms of it, such as that used by Ubisoft, require that a PC be connected to the Internet during the entire duration of the software’s use. Hence the controversy; many users feel they shouldn’t be restricted to using their software only when online.
Device Driver Copy Protection
Another form of copy protection that relates primarily to computer software, device driver copy protection installs a new driver on a computer as part of a program’s installation process. The responsibility of this drive is to validate the software and also to protect the software from attempts to circumvent it or run it without a proper registration key or disc. Some examples of this technology include Starforce and SafeDisc.
These forms of copy protection are controversial because the device driver can interfere with a computer’s normal operation in some cases. Users of software protected through this method have sometimes experienced a degradation of optical drive performance. The device drivers can also be a security risk; in 2007, Microsoft patched a SafeDisc related vulnerability in Windows XP. The driver could be exploited by malware to gain administrative access.
High-Bandwidth Digital Content Protection
Developed by Intel , HDCP is a relatively recent form of copy protection. It circumvents the traditional problems associated with content encryption by moving the responsibility of encryption from the content itself (the disc, file, or other media) to the devices playing the content.
HDCP is designed to protect content that travels across a digital connection such as DisplayPort, DVI or HDMI. The device sending the content and the device displaying the content must have valid HDCP encryption keys and must authenticate. As you might have guessed, this is the form of content protection used to control Blu-Ray. Like other forms of encryption before it, HDCP has been cracked through the release of a master HDCP key, which was most likely reverse-engineered.
Remember, these are just the forms of copyright protection that most commonly apply to CDs and DVDs. There are other forms of authentication and encryption that are frequently used to protect digital content, such as music downloaded from the iTunes store.
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