Hash Function Security Assessment Model Research Based On Statistical Randomness

With the development of science and technology, human society has entered the internet age, people’s lives are now dependent on the network, the popularity of online shopping,online transactions,e-government,e-tax,e-commerce and others that provides convenience to people lives has dramatically increased.In doing so, the demand for information security or data security has also become an increasingly urgent research topic.Hash function plays an important role in ensuring information security,choose safe one-way Hash function is important, and the secure hash function,In theory it is difficult to prove,but in theory the most important points is a single isotropic and pseudo-randomness.This thesis is to study the randomness assessment of the Hash function,where a randomness assessment index system and model is proposed,Quantitative information of the index value will be measured by the membership function in fuzzy mathematics,Then based on fuzzy comprehensive evaluations level comparative law and an entropy law is used to assign weights to the indicators or sub-features, Finally through layers of assessment,comprehensive quantitative assessment of the results of the Hash function randomness is made.First, the thesis introduces the background and significance of the password randomness test,then give the research status, The randomness testing methods for traditional iterative structure of hash functions and the chaotic structure are also introduced.Secondly, a brief introduction is given about the basic knowledge of the randomness test, then, the Hash function test of the randomness test are classified, set up the randomness evaluation index system of Hash function,the random test results are changed into fuzzy using the fuzzy mathematics membership function, and then be evaluated in accordance with the fuzzy comprehensive evaluation model, bottom-up layer by layer, and finally get a comprehensive quantitative assessment of results of the hash function, then apply this evaluation model to evaluate the randomness of SHA-1.Then, improve the assessment model weight assignment method, combine the application level comparison and information entropy,empower the index item or sub-characteristics of rights re-assignment, application of this improved assessment method on the SHA-1randomness evaluation, the evaluation of the effect has been improved, in addition recently the Skein function and a typical chaotic Hash function were assessed.Finally, summarize the content and major work of this study, pointing out the deficiencies and areas for improvement, a plan for future research directions and content is given.