The Research And Implementation Of Software Shelling Technique

From the appearance of computer, its technical development has changed and improved to a great extent, every kind of new technique, new idea flows out continuously. Every kind of software, from several bytes, tens of bytes to several compact disks, thousands of sharing software and business software become more and more, the technique content become gradually complicated. The technical secret of excellent software, it usually becomes the point that others steal. With popularity of the way that software issue in a sharing way on the network, the urgency of software protection and data encryption techniques was more prominently displayed.The current protection technique includes two kinds of methods that the software encryption and hardware encryption, the hardware protection is a rather safe technique. But the cost is very high, the pure software encrypting is booming because of economy and convenience, and the most familiar is the technique of shell encrypting currently. The purpose of the question for study aims at such circumstance, concentrating on the analysis of the characteristic of prevalent shelling-off technique. We design a practical scheme and then design software.In the first place, we make a penetrating analysis of current executable format in Windows platform, that is, Portable Executable Format. We analyze Anti-Trace technique, manual shelling-off technique, and the characteristic of shell that every kind of tool disposed from the concept and loading process of shell. We especially analyzed the structure of shell and its executing cutting mechanism.We realize that traditional shelling software has already been extensively studied, and the protective ability is not strong, the question for study adopts modularizing composition to design a style of simple shelling tool. The disposal of file uses public compressing function library APLIB. According to the particularity of resource section in the file, resource directory and resource data are respectively disposed in detail. At one time, in order to improve safety, wenecessarily change the import table of original file in form and dump it, also design relevant import table structure. Confirming rough project, then basically realize the effective protection to many simple software. At the same time, starting from the angle of Anti-Debug technique, we thoroughly analyze the means how protect procedures in order to avoid cracking more rationally. Then adopting relevant measure to realize during the design of procedure.Finally, problems of the shelling tool are analyzed in subject, and we give some main means that improve security of applied software. In addition, this thesis shows some relevant basic knowledge of Assembly Language Procedure Design under 32-Bit Windows Environment.