LaserLock is a

copy restriction Copy protection, also known as content protection, copy prevention and copy restriction, describes measures to enforce copyright by preventing the reproduction of software, films, music, and other media. Copy protection is most commonly found on ...

system for

CD-ROM A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains data. Computers can read—but not write or erase—CD-ROMs. Some CDs, called enhanced CDs, hold both comput ...

s with 32-bit

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

applications introduced by MLS LaserLock International Inc. in 1995. LaserLock is supposed to check whether the original storage medium of a program is inserted. This check can be done regularly or only once during the installation of the program. If the disk is not accessible, an error window is displayed. It uses a combination of encryption software and an optical mark on the surface of the disk. The protection code is embedded into an

executable In computing, executable code, an executable file, or an executable program, sometimes simply referred to as an executable or binary, causes a computer "to perform indicated tasks according to encoded instruction (computer science), instructi ...

file on the disk using a proprietary tool. This file, which is responsible for searching for the physical mark on the disk, is encrypted and gets multiple layers of protection against code analysis to impede

reverse engineering Reverse engineering (also known as backwards engineering or back engineering) is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accompli ...

. The size of the encrypted file varies from 20 MB on CD-ROMs to 40 MB on DVD-ROMs or occasionally only 5 MB. LaserLock includes a hidden directory on the disk which contains corrupted data. When the disk is copied, the read device encounters errors due to the hidden directory. Copying leads to unstable behavior of the copied software and often to

bad sector A bad sector in computing is a disk sector on a disk storage unit that is permanently damaged. Upon taking damage, all information stored on that sector is lost. When a bad sector is found and marked, the operating system like Windows or Linux will ...

s that make it impossible to use without the original disk.

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See also