Applied Research On AES In Distributed Management Information System

This dissertation"Applied Research on AES in Distributed Management Information"originates from the actual project. Widely applied along with the distributed management information system day by day, the information security question also more and more receives seriously. Under such background, this dissertation studies AES(Advanced Encryption Standard) and its improved program, and applies it in the actual system. This dissertation will certainly promote the positive role to the information security's research and application.Through analyzing the design criterions, the basic principle and the overall construction of AES, as well as using MATLAB to realize it, we may discover that, AES is one kind of SP-type block cipher; its S-Box is the algorithm's only nonlinear component, also is one key component of deciding entire algorithm's secure. Therefore, analyzing the S-Box performance, enhancing its security is one of this dissertation's main research directions.This dissertation uses MATLAB to solve the S-Box and the inverse S-Box algebraic expression, analyzes the S-Box's algebraic properties in nonlinearity, difference uniformity, strict avalanche criterion, affine transformation period and iterative-output period, discovers that the S-Box is not perfect, has the problems that the algebraic expression is too simple, the affine transformation period and the iterative-output period are excessively short. Through adjusting the S-Box's computation order, choosing appropriate affine transform pairs, increasing an affine transform, this research designs the new S-Box. The improved S-Box has the properties: strict avalanche criterion is 372, the S-Box and the inverse S-Box's algebraic expression has 254 items; the affine transformation period is 16; the iterative-output period is 256. This dissertation takes the Heilongjiang info port's business management information system as an example, introduces the distributed management information system development involved the demand investigation and study, the system design, the code realizes and so on. This dissertation completes the improved AES with C++, carries on the optimization and encapsulation, enhances its performance and the reusability, and applies it in the system to protect the sensitive information in the system.