Research And Implementation Of Shell - Based Software Protection Mechanism

With the development of information technology, more and more people are using computer systems and software to improve efficiency, the computer software is more powerful now, the development costs become higher. In order to prevent the software from being illegally cracked, piracy and ensure the healthy development of the entire software industry, therefore, software protection has played a pivotal role in maintaining the interests of developers. Before publishing software, the encryption protection measures should be adopted to protect it:hardware encryption and software encryption. Although the security of hardware encryption is relatively high, but the cost of the development is more expensive, in soft encryption protection, packers protection technology is the most popular, economic, security protection technology.Packers protection technology refers to the file compression and encryption, modifies some file information of the original file and the execution order of the original file:First the shell is executed and then the original program is again executed. After the file has been modified, it is not only modified the execution order of the files, but also the static profile is changed, in this way, it can effectively prevent crackers illegally modified the file, and crack.This paper studies the PE file object which is based on32-bit Windows platforms, Analysis the structure of the executable file, introduce the existing shell software, shelling and some software reverse analysis tool of importance. When researching and summarizing the current mainstream software protection techniques and analysis techniques from the positive and negative aspects, I propose a new model which is based on software protection shell technology, multiple protection technologies are integrated into the protection model, Such as flower instructions, code deformation, SHE, anti-tracking, anti-debugging, encryption compression and so on, it can be Effectively prevent the software being decompiled static and dynamic sub-track, so as to achieve the purpose of protecting software.Finally, the most modules of the packers software have been developed and implemented, the shell is developed in Assembly and the main program is developed in C++object-oriented language, the question for study adopts modularizing composition to design a style of simple shelling tool. The use of software engineering ideas:frame design, outline design, detailed design, software testing and so on, to achieve packers software protection tool, in order to improve safety, The disposal of file uses public compressing function library APLIB.According to the particularity of the resource section in the PE file,the resource directory and resource data are respectively disposed in detail, and change the import table of original file in form and dump it. Then adding the shell to the new section blocks, while modifying header information, Ultimately, Achieving a resist piracy, cracking software protection tool.