Research On Decompilation Of AS Based On SWF

Today there are many excellent software with the development of computer science and technology.These software products have accumulated a lot of good developers' design ideas and experience.We must analyse the software source program in order to understand and learn ideas and principles within software;and we should obtain various parameters of the software.If we want to develop software compatible with the software,we should get the software source codes.However,in order to gain advantage in the market competition,software developers generally will not be open source codes.Therefore,decompiling on software has become a frequently used method to development and technical personnel.With general application of computer software,decompilation becomes important research field in software reverse engineering.Many practical sites show its significance,such as migration of software programs,security analysis of business software,cryptanalysis, and reuse of software.Decompilation is the process which translates source programs writted by machine-code level language into corresponding advanced language program writted by compiler level language.Decompiler is looked as a software tool,whose function is equivalent to the reverse process of compiler.It is an important component of the software reverse engineering.SWF is a special format of Macromedia's animation design software—Flash.It is a animation file format which support vector and bitmap graphics,which has the characteristics such as not having the scaling distortion,no small size document and so on.It uses streaming media technology,you can play it while downloading.Nowadays it has been widely used in web design,animation production and other fields.It is composed by the header and the body.In order to interactive better user with interface,we introduced action script language ActionScript(short for AS) to Flash.ActionScript is the Flash scripting language.It is similar to JavaScript which is an object-oriented programming language.This article describe the compilation based on AS. The main contents of the thesis are following:(1) Discussed the main technology on compilation,including analysis of data flow,analysis of control flow, identification of library functions,and so on;(2)Described some main patterns of decompilation.We selected a decompilation pattern based on pattern recognition which is suitable for our system.Syntax analyis,grammar analyis,syntactic analysis, semantic analysis,generation of intermediate code,generation of control flow graph. (3)Introduce the running environment of decompiling system—Decompiler.Translate text file into binary file,and comply successfully compilation from binary file to source file by using the idea of pattern matching.The main contribution of the thesis is the following,designed and finished the decompilation system on ActionScript based on SWF,which can meet the need of customers,and fulfill the recovery of AS stored in SWF,and supply basic research to the butter development of future decompliation.