Research On Public Key Cryptographic Algorithm Recognition Technology

Public Key Cryptographic Algorithm plays an important role in information security. For its security mechanisms, it has been widely used in the security technologies such as data encryption, digital signature, data integrity check and etc. The research on recognition of Public Key Cryptographic Algorithm is very important for reverse analysis on key electronic equipments and softwares.The selection of algorithm features is the first prerequisite of the recognition of Public Key Cryptographic Algorithm. This thesis analyzes the features of Public Key Cryptographic Algorithm from three respects which are encryption principle, implementation and reverse features of cryptographic function-library and proposes the Realization Characteristics of Function-Library of assembly-level Public Key Cryptographic Algorithm. Then according to the analysis of algorithm recognition and Model Checking Technology, a recognition method for Public Key Cryptographic Algorithm is proposed based on Model Checking with Automata Theory. Secondly, the encrypted primitive is designed with corresponding instances and the time sequences of the Realization Characteristics of Function-Library. Therefore, a Finite Statement Automata of Public Key Cryptographic Algorithm can be established upon the invocation sequences of the encrypted primitive. Thirdly, the target binary files are pre-processed to filter the abnormal functions of Public Key Cryptographic Algorithm based on FLIRT Technology. Then an automatic modeling algorithm with these abnormal functions is designed and the sequence diagram of function invocation which could be transformed to Pushdown Automata is also constructed with control flow modeling. Finally, a Model Checking Algorithm is proposed to detect the strongly connected components of the directed graph based on Tarjan.This thesis proposes a Prototype Tool for the recognition of Public Key Cryptographic Algorithm based on the Model Checking method with Automata Theory. The experimental results demonstrate that the Prototype Tool can accurately recognize the common Public Key Cryptographic Algorithms in target binary files and the automatic modeling and checking of binary files can effectively improve the recognition efficiency.