Software crack is a reverse software development. This software is modified to remove the security methods. Copying and using copies in almost every developed country is illegal. There have been numerous litigation against software, but most of all for the distribution of the duplicate product, the defeat of defense, and the difficulty of proving guilt.
The most common software crack is to modify the binary setting of an application that causes or prevents a particular key branch of the program execution. This is done with reverse programming by compiling the compiled code using a debugger until the software cracker fails to link the software that primarily protects the software.
The binary code is then modified by the debugger or hexagon editor to replace a branched opcode so the keyframe always executes a subroutine or skips it. Almost all common software cracks are such a version.
Proprietary software developers are continuously developing techniques such as code decay, encryption, and self-modification to make this change more and more difficult. In the United States, the adoption of the Digital Millennium Copyright Act (DMCA) legislation resulted in illegal software violations and dissemination of information to enable practice.
However, the law was severely investigated in United States justice cases that were only for personal use. In May 2001, the European Union approved the European Union's copyright guidelines as the copyright infringement software was declared unlawful in the Member States after the adoption of national legislation under the Directive.
The first software copy protection was early Apple II, Atari 800 and Commodore 64 software. Especially the game publishers have made an arms race with crackers. Publishers have been demanding more complex countermeasures to try to prevent unauthorized copying of their software.
One of the most important ways of early copy protection was running a program that simulates the normal CPU operation. The CPU simulator provides several separate functions for the hacker, for example, to scan through a processor command simultaneously, and to scan CPU registers and modified memory areas during the simulation run.
Apple II has a built-in opcode disassembler that allows you to decrypt the raw memory for CPU opcodes and use this to examine what the copy protection will be. In general, there was little protection for the copy protection system since all the symbols are visible through the simulation.