Research On Anti-DPA Attack Technique Of Wlan SM4 Algorithm

Wireless local area network(WLAN)has been widely used in people's daily life,which has so many advantages,such as open interconnection,convenient deployment,flexible access,economical price and so on.Due to the open nature of wireless networks,however,the security problems for the WLAN have become increasingly prominent.Encryption technique is usually adopted in the WLAN,to ensure the secure transmission of information.The SM4 algorithm,which is an encryption algorithm based on the WLAN national security standards,has high complexity and high security.With the development of the side channel attack technique,however,the SM4 algorithm is vulnerable to power analysis attack when hardware encryption is carried out,which seriously threatens the security of the WLAN.In order to find out the security vulnerability of power analysis attack technology,and put forward corresponding protection measures to enhance the security of WLAN devices,the attack and protection techniques of the SM4 algorithm are focused on in the dissertation,and the specific research contents are as follows:(1)The SM4 algorithm is studied,and a low-complex hardware implementation of the nonlinear device S-box is analyzed,which provides a lot of advantages for implementing the algorithm on the hardware development platform.(2)By analyzing the potential attack points in the SM4 algorithm,the first-order differential power analysis(DPA)attack method for the output of the S-box is studied.Then,a method of the second-order DPA attack,which selects the leaked power consumption information of the S-box input and output,is proposed,for the protection of the first-order mask in the SM4 algorithm.In the proposed scheme,the influence of the first-order mask in the round operation is eliminated,through a certain operation operation,in order to achieve the purpose of the second-order DPA attack.The attack process is simulated and the Hamming weight of the intermediate data is used,to represent the power consumption information,which verify the feasibility of the proposed attack method.(3)Since the SM4 algorithm is vulnerate to DPA attacks,a protection scheme for the SM4 algorithm is designed,which can ensure the security of the algorithm by adding first-order and second-order masks to the key expansion and encryption/decryption algorithms,repectively.The process of adding first-order and second-order random masks to the nonlinear S-box is derived in detail,and the first-order and second-order DPA attack methods are used to carry out the attack simulation test for the protection of the algorithm.The simulation results show that the mask scheme can effectively resist the second-order DPA attacks,and to some extent,can meet the needs of WLAN for security performance.(4)The hardware implementation scheme of the SM4 algorithm is designed,and the SM4 algorithm with mask protection scheme is implemented on a Field Programmable Gate Array(FPGA).The implementation processes of the key expansion/encryption algorithms are first given in detail,and the correctness of the algorithms is verified by the simulation tool Modelsim.And then a hardware encryption/decryption platform is built,where the encryption/decryption transmissions of the picture information are completed on the platform,thus the correctness of the hardware implementation for the algorithm is verified.