To avoid losses brought by pirated software, an increasing number of users begin to protect optical disks via encryption. The commonly applied theory of the main encryption methods is to make use of certain non-numerical information which is not reproduced and can not be copied. To let users know this technique further, we will introduce in detail as follows.
CSS encryption technology
CSS is the acronym of Content Scrambling System. The main theory of this technique is to divide optical disk into six parts and encrypt them by different methods. Only under the circumstance that users own the corresponding decoder of the optical disk can they deal with data in it. Furthermore, the detailed operating process is that users are supposed to process the information in the optical disk with encode procedure at first. As a result, if users would like to get access to those data, they have to decode them. This technique can guarantee optical disk data security to some extent.
APS encryption technology
APS is the acronym of Analog Protection System. This technique focuses on preventing copying from one optical disk to another. The main theory applied in the technique is to affect the copy function of optical disks with certain signals via a Macrovision 7 chip thereby producing horizontal stripes and uneven contrast, etc. This technique can maintain optical disk data safe effectively.
Shell encryption technology
Actually the so called shell is the shell of all executed files and it will decompress the original procedure for users with the procedure in internal storage, and then give control rights back to the decompressed program which is unknown to users and will not influence the speed of execution since all those operations are performed in memory. If users set validate code for software phase locking or key disk in shell procedure, they have completed shell encryption to maintain optical disk data safe. If users want to prevent program code from being altered by hackers or being followed by malicious users, this technique is the best choice to insure data security.
CPPM, namely Collaborative Project Portfolio Management, commonly used in DVD-Audio adopts CSS encryption technology which can encrypt optical disk via placing key into lead-in area. However, there is no title key in sector header because the key is replaced by album identifier. What's more, this technology has the same detecting schemes with CSS in the way to guarantee data safety.
There exists a tremendously large amount of software which adopts encryption technology on the current market like utility software, multimedia software and anti-virus software. The application of such technologies can protect benefits of software market to some extent. Furthermore, it will prevent malicious copy or usage so as to protect optical data safety effectively.