Automatic Search Of Differentials For Graphical Input Algorithms

Cryptography,as the theoretical basis of data transmission security,has become a hot research direction under the background of increasing attention to information security.Block cipher is widely used in practical environment because of its advantages of fast encryption speed and flexibility.Differential analysis and a large class of cryptanalysis methods derived from it have been proved to be effective in many algorithms.Therefore,for a new algorithm,the nature of its anti-differential analysis is a very important aspect to evaluate its security.The first step of differential attack is to find an effective differential route.The automatic search of differentials is a hot issue in recent years.Establishing the SMT model of differential search and using STP solver to solve it is one of the mainstream automatic differential route search methods.This technology has been proved to be effective in many Papers and algorithms,and the technology is becoming more and more mature.However,this method for automatic analysis of differentials require users to establish STP models for every encryption algorithm and input them to the solver for solution.This requires users to master the corresponding cryptographic knowledge,familiar with STP model and the input language format of the solver.As a result,the threshold of the use process is high,the operation is cumbersome and error-prone.In this paper,according to the principle and specific steps of automatic differential route solving,the graphical input of cryptographic algorithm is realized by adapting the open source tool flow-chart.Using the text information of graphical input,the automatic establishment program of the model is developed,and the CVC code which can be supplied to the solver is obtained.Finally,a set of practical tools is realized to obtain the differential route by using the graphic input and algorithm parameters of the algorithm.In this paper,we introduce the specific process of development and some noteworthy details.In the appendix,we give the main parts of the source program.Finally,we use this tool to search the differentials of 6 rounds 128 bit AES algorithm,?rounds 32 bit Speck algorithm,7 rounds 64 bit Speck algorithm and 7 rounds 96 bit Speck algorithm,and get the experimental results,which verify the practicability and effectiveness of the tool.