Research And Analyses On The Sha Hash Algorithm 1

In this paper, we discussed the inner function of the SHA-1algorithm.We primary discussed the logic function ft and plaintext spread sequence Wt which play important role in the SHA-1algorithm. We did some work on analysing the SHA-1,and also provide some reference for designing new Hash algorithm. We computed some function and got some relevant conclusions by controlling variable method carries on the overall analysis in the main body to explore the specific role of the function in the SHA-1.(1) Logic function ft has good confounding, but its own collision resistance is weak. In overall SHA-1algorithm, combined with the model computation and information diffusion algorithm, it has to further strengthen the completeness of SHA-1algorithm, and enhance the overall finite difference analysis of the resistance of the algorithm.(2) Information diffusion sequence Wt has stronger ability of proliferation, it plays an very impor-tant role in the overall SHA-1algorithm, the stand or fall of its diffusion ability relationship with the SHA-1algorithm whether has the cryptographic properties of a Hash function.(3) Modular addition and subtraction operation have certain linear characteristics, further confus-ing the SHA-1algorithm plays a role and to some extent, enhance the overall ability to resist differential analysis algorithm.