Application Research Of Opaque Predicate In Javascript Code Protection

As the rapid development of cloud computing technology, many CC-based new Web services were proposed. These services communicated by B/S in JavaScript beyond system platform. And the condition users could get the JavaScript source code by browser easily led to greater challenge of security of network information and source codes. Meanwhile, Most of code protection technologies were developed based on complied language like C/C++ or Java platform currently and less on interpreted language like JavaScript platform. Therefore, it is a meaningful and economic research project to protect JavaScript security.We analyzed the research condition and weakness of code protection technologies currently, and we discussed and improved many code protection technologies in JavaScript platform, as well as proposed an effectiveness comprehensive evaluation model for these technologies. In this paper, we mainly researched the contents below.Firstly, we defined the concept of N-states opaque predicate that improved from simple two-states opaque predicate and put forward two methods to constructing advanced opaque predicate. One of methods called N-states opaque predicate based on two-dimensional Arnold cat chaotic mapping, and the other one was hash-based N-states opaque predicate. We also detailed the core framework, algorithm structure and implementation of these two construction methods.Secondly, we improved and implemented JavaScript control flow flattening algorithm by mean of N-states chaotic mapping opaque predicate to resist hacker’s attack of constant value spreading analysis that the problem traditional control flow flatten technology faced. Experiment proves that this method could resist of many source code reverse analysis.For the problem of robustness and invisibility existed in conventional software watermark technology, we proposed and implemented a JavaScript software watermark algorithm based on N-states hash opaque predicate. This method can improve the anti-interference ability and privacy of software watermarking in our test case.At last but not least, A dynamic self-adaptive PCA-based code protection technology effectiveness comprehensive assessment model was proposed to fill the gap of accurate quantification in the area of effectiveness of JavaScript code protection technology, and for evaluating the technologies raised in this paper. Experiment result shows the effectiveness of this model.