Research On Virtual Execution Protection And Attack Evaluation Of Large Game Software

Massive Game Software is the creative industries under the new situation, game bring developers and operators a lot of revenue annually. By the development of malicious crack of reverse game, the benefit chain is more complete. It is very serious threats to the game’s core algorithms and leakage of confidential information. More and more code analysis, dynamic debugging, running track and other static and dynamic methods are widely used, combined with cracking techniques and tools are readily available, making the game software is dangerous "white box environment." Currently, many ways is used to protect software. These ways are not systematic and lack of theory. Repeat use of some separate methods reduces the protection. The relative lacks of systematic research make effective protection against game software cracking less.In this dissertation, we choose the highest form of security requirements to run the most complex massive game software as the research object. Study on many aspects including software protection under binary form and balance the effectiveness of protection methods and strategies, etc. We focus on the needs of key code protections by analyzing attacked characteristics of game. The balance problem was concerned in running and consuming performance. We get security needs of different code blocks by analyzing the attacking characteristics of the game software. Security and performance overhead balance issues were discussed under virtual execution condition. In order to improve the objectivity of the software protection evaluation, enhance the security model and improve the protection relevance, researches were carried on the protection of attacks.The main work of this dissertation is described as follows:I, The effectiveness of traditional software protection was restricted. In order to make the game software virtual execution protection, we construct a set of related security model, we discuss the key code obfuscation, encryption and white box instruction code transformation. Using a combination of remote white box transformation and the game C/S architecture, a new security idea is presented. Virtual execution protection model (VEP) was constructed, and security model are analyzed to verify.II, In order to avoid the dynamic execution of code stored in plain text defects, we discuss how to effective against a software implementation of MMORPG code obfuscation transformation. The security model is improved by enhancing the obfuscation algorithm. Combined with the characteristics of large game software architecture, implementation complexity and dynamic security protection have been strengthened by remote white box cryptography. Through the virtual instruction new structure and distributed processing mechanism, the distribution and transformation of atomic Handler function to strengthen the security of random transform, carried on the comparative analysis of the complexity and the performance of positive transformation, provided a general reference method for the game software protection.Ⅲ, The protection system of support is studied and discussed based on the game software virtual execution protection model. In view of the game software attack patterns, we analyze the performance of balance problems caused by virtual execution protection transformation. In the technical realization, designed by introducing multiple dispatch, secure virtual execution instructions and deformation models of engine, the safety of the virtual execution environment was improved. The anti debugging and tamper proof problem of dynamic execution of game software was solved by using instruction register and "sentinel" mechanism.IV, A Petri network was constructed in this dissertation. The evaluation attack model is built. A calculation method is proposed which derived based on the analysis and the attack cost. The power sources of the attacker determine the effectiveness of software protection. In order to improve the accuracy of the evaluation process, the attack strength attack evaluation to improve by using the structure of attacking perception factor. This dissertation provides a new ideal on the evaluation method for effective attack modeling software protection.VI, Part of the theory of VEP modeling and measurement of the model is validated. Firstly we design and provide a set of VEP based model for the game software virtual execution protection platform NISL-VEP by using the software of virtual execution model of VEP thought, Secondly we design and provides a set of Attack-Petri automatic reverse attack test platform by using M-AMMPN attack model based on Petri net. Finally in the two platforms, we carry out data analysis and verification of some of the key issues in the theoretical model.Through the experiment, we discuss the implementation of performance problems which may be caused by the game software safety protection. Through the method of reverse analysis, the virtual executions transform protection after the game software to obtain the index variable and compared using attacks. For a given sample by reverse attack experiment based on the evaluation, the given attack model has been verified. The experimental data show that, virtual execution transform to improve the game to prevent reverse and external attacks on security, performance and efficiency can be raised greatly.