The Block Cipher Encryption Research Based On Chaos

Network security is one of the hottest problems for the next generation of Internet. But the encryption algorithm is the core in the problem. To meet the increasing complicated and real-time secure communication demands, we should, on the one hand, choose more sophisticated encryption algorithm to increase the security of information, on the another hand, choose more efficient algorithm to realize fast computation and give clients a good user experience. And at this point, the appearance of chaos seems to solve the problem. Chaos theory as the recent fast development non-linear science is used to design secure and fast encryption algorithm needed by the next generation of internet communication.In this paper the Logistic mapping is choosed as the non-linear model, and some chaos properties are added into the SP model which is a structure of block cipher encryption. Then a chaotic block cipher encryption algorithm combined with Logistic mapping and SP model structure is designed. According to the properties of chaos, finding the strategy of applying chaos properties into S boxes and P boxes is required for the realization of chaotic S boxes and P boxes. Further more, the S boxes and P boxes are not only designed but evaluated with corresponding performance introductions. At last, according to present cipher security analysis theory, some security analysis is presented on our encryption algorithm. They are key space analysis, key sensibility analysis and some S boxes abilities analysis. To test and verify the efficiency of this algorithm, a simulate CS communication environment and a session protocol like SSL are designed for testing the time delay when information transporting under respective encryption and non-encryption conditions.As we know some properties in chaos, like track pseudo-random, sensitivity to parameters and initial values and un-forecastable for track in long time, have a nature relationship with confusion and diffusion in cryptography. In this paper those properties are used in our algorithm to improve the security. Meanwhile, the encryption/decryption time is kept as short as possible by using cache mechanism. Usually, the time cost on encryption includes the generation of sub-keys and mappings in S boxes and P boxes from plain text to cipher text. And those mappings information can be saved in the memory and reused by other blocks. In this way, the algorithm will have a good efficiency.