Research On Data Security Storage Algorithm In Cloud Environment

At present,cloud storage and its application are becoming more and more widely.However,data security problems such as data leakage,tampering or destruction may occur in the Internet environment.So,how to safely store data in the cloud environment has become a research hotspot.Therefore,the plaintext data can be changed into ciphertext data by using the encryption algorithm in cryptography to achieve the function of data hiding and protection,then the idea of secret sharing is used to realize the data information segmentation,distribution and storage,to ensure the integrity and security of the data in the storage process,and to achieve the purpose of dispersing security risks.According to the existing secret sharing schemes and literature research,the thesis proposes a new secret sharing scheme based on GF(2~8) domain.On this basis,the research of data encryption algorithm is carried out,and a security sharing scheme based on hyperchaos and SHA-256 algorithm is proposed,which is combined with cloud storage.The main contents of the thesis are as follows:(1)In traditional Shamir threshold scheme,the computation cost of polynomial is high and the efficiency of sharing secret is low.The thesis proposes a new scheme based on GF(2~8) domain,which is more suitable for the decomposition,sharing and recovery of confidential files.In the new scheme,secret files are grouped into different polynomials in GF(2~8) domain by byte grouping,and the points generated by polynomials are stored in sub secret files for distribution.The recovery can be carried out based on Lagrange interpolation.Through the analysis and comparison of numerical examples and experiments,it shows that the scheme is more general than the traditional scheme,the operation efficiency is improved,and it is more suitable for binary computing system.At the same time,the operation rules are different from GF(p),which is more complex,making it more difficult to be deciphered,and the security is better.(2)Aiming at the problems of existing data encryption algorithms,such as small key space and low practicability,this paper proposes a secure sharing scheme based on hyperchaos and SHA-256.Firstly,SHA-256 algorithm is used to make the initial value of hyperchaotic system related to plaintext data,so that different chaotic sequences are used to encrypt different data.Secondly,the four-dimensional hyperchaotic system is used to generate uncorrelated chaotic sequences to encrypt them.Finally,the scheme based on GF(2~8) domain proposed in(1)is used to decompose,distribute and recover them.Through the experimental comparison and analysis,using the hybrid encryption of hyperchaotic system and SHA-256 makes the key space large and the initial value sensitive,and the correlation between the key stream and plaintext data is no longer fixed,which enhances the randomness of the key stream and the difficulty of decoding the encryption algorithm to a certain extent.On the other hand,using the scheme based on GF(2~8) domain in stored procedure can effectively prevent the problem of being stolen and damaged,which has lower risk and higher security.(3)The use of cloud storage services is not foolproof,there may be data leakage or no encryption of sensitive data directly on the cloud and other security risks.In order to avoid such problems,the solution proposed in(2)uses the Hadoop cloud platform as the basis,and designs a secure cloud storage solution.The data is first encrypted by hyperchaos and SHA-256 encryption algorithms,and the obtained data information is then decomposed and stored using the finite field GF scheme,and the obtained multiple shares are stored in the cloud through the write process.At the same time,the security authentication in Hadoop can perform multi-layer authentication for users who are accessing.When the user passes the authentication,these ciphertexts can be obtained,and then multiple ciphertexts can be restored by Lagrange interpolation.Through security analysis,the scheme can ensure the security of user data and realize the security storage of data in cloud environment.