Protection Algorithms And Implementation Of MSIL Code And Native Code

Computer software is a kind of special goods that can be easy copied, tempered. Along with some political and economic reasons, computer software protection is very weak. This dissertation brings out several technical ways to enhance intellectual property protection within the software domain.First this dissertation introduced some existing protection technologies, including: hardware assist-software protection, shell technology, obfuscation, software watermarking & tempering-proof technology.After the introduction of existing protection technologies, I will bring out my protection solutions. (1) ABSMC is a new kind of obfuscation protection. (2) SADGW: an improvement to well known dynamic graph software watermark. (3) HGI & TVMBISA: new kinds shell technology.ABSMC will add some dynamic codes to the target programme(using a automation to control the code translation). These dynamic codes change with the running of the target programme. Therefore, it is hard for attackers to understand the intention of the target programme. In other words, ABSMC can block nearly all the static analysis and slow down the dynamic debugging. Therefore, it is safer than the traditional ways. SADGW analyses data structures of target software, and get out some of the data structures, merge them with dynamic graph software watermark, finally obfuscate codes using these data structures. So when attackers modify the watermark, these data structures are modified together. The result of attackers' actions is making target programme collapsed.HGI technology is aiming native codes protection. It makes full use of high security encryption algorithm, and split target software into blocks, then encrypts every block. The technology ensures there is only one block is in origin form, and cross check between blocks makes attacking the technology more hard. On this basis, TVMBISA use a thin virtual machine to enhance the execution speed.I have completed an extensible protection system including de-assembly, de-compile, user require control, some protection plug-in (each plug-in is a implementation of one protection technology). My system not only provides a platform to implementing testing my algorithms, but also can serve for algorithms will formed in the future as long as fitting for our interface. The manage code parts of my system were written by c# & MSIL, the native code parts were written by C++. Though my system only support parts of the instructions, the execution results show my system is promising. At last, I use Microsoft's benchmark tools (AHC & LCSC Managed Code Benchmark) to prove my algorithms & implementations are powerful. In the testing data, you can find the cost, resilience, stealth are all fit the original plan.