Abstract: Constructing the safety opaque predicate is the major issue in code obfuscation and the key to it lies in using opaque predicates．In order to form a chaotic opaque predicate,the En_Logistic was proposed through improving the Logistic chaotic,and then it was applied to the construction of the opaque predicate clusters．The chaotic opaque was applied in the code obfuscation process．In this experiment,different methods of inserting chaos opaque predicate into program branches and sequence blocks were given．The program complexity evaluation and the control flow complexity evaluation were given in the application process of code obfuscation．Additionally,security analysis shows that the chaotic opaque predicate has higher security in fighting against static attacks,as well as the dynamic．And better effectiveness in the code obfuscation is verified in this experiment.

Key words: Chaos theory,Logistic mapping,En_Logistic mapping,Opaque predicate,Code obfuscation,Software protection