Research On Technology Of Cryptogram Algorithm Recognition Based On Similarity Decision-Making

Cryptographic Algorithms have been played an important part in information security field, Research on technology of Cryptographic Algorithms Recognition has great effect on reversing of pivotal electronic equipments, extraction of sensitive information in internet and security protecting of computer systems.The first step of Cryptographic Algorithms Recognition is to select proper characteristic, this paper has studied characteristics of Cryptographic Algorithms from three aspects as encryption characteristics, reversing analysis characteristics, general and special characteristics, and then given some description of typical Algorithms' characteristics.According to general statistic characteristic, we have proposed an algorithm which is based on Cosine value of two vector's angle to give the similarity of Cryptographic Algorithm Essential Process, and have constructed unitary Cryptographic Algorithm characteristic vector by assembling and training many swatches of essential processes in Cryptographic Algorithm realizing. In order to enhance the stability of decision-making result, we have introduced feedback mechanism to modulate benchmark characteristic vector interactively.Aiming at special characteristic of Cryptographic Algorithm, we have proposed a Cryptographic Algorithm Recognition method which is based on automaton of core instruction sequence, this method can conclude algorithms' name based on Cryptographic Algorithm Essential Process Recognition and also can deal with code confusion problems caused by register renaming and instruction exchanging by dependence analysis.This paper has designed a Prototype System which uses similarity decision-making result to direct core instruction sequence recognition. The testing shows that the similarity of Cryptographic Algorithm Essential Process can reach 0.90, core instruction recognition can locate core expression of Cryptographic Algorithm exactly and effectively determine Cryptographic Algorithm in target code.