Research On Secure Cloud Storage Scheme Based On Secret Sharing

In recent years,with the rapid development of information technology such as big data and cloud computing,cloud storage has become an emerging storage technology developed in cloud computing technology.Cloud storage is essentially a cloud computing system.It has the characteristics of huge storage space and data storage and management as the core.And it can provide users with extremely efficient and convenient storage services at a very low cost.However,security incidents such as data leakage in the process of providing storage services make the security of cloud storage a topic that cannot be ignored.Encrypting data and then storing it has become the main means to solve the data security in cloud storage,but how to manage the key is also directly related to the security of data.As one of the important research directions of cryptography,secret sharing is a technology that divides and stores secrets.It can disperse risks and prevent attackers from invading,thus achieving the purpose of information security and data confidentiality.It provides a reasonable and effective way for key management.Therefore,the research of secret sharing scheme is helpful to its practical application,especially the development of cloud storage security.Based on the existing secret sharing schemes and Lagrange interpolation method,the threshold secret sharing schemes based on bivariate polynomial is studied,and the combination of new secret sharing scheme and secure cloud storage is researched on this basis.The main research work of this paper is as follows:(1)Aiming at the problem that the selection of bivariate polynomials in secret sharing schemes is not arbitrary and can not meet the actual situation,a threshold scheme based on bivariate Lagrange interpolation polynomial is proposed to realize the arbitrariness of the selection of bivariate polynomials.The bivariate Lagrange interpolation method on rectangular points mesh is used to realize the selection of participants in the secret recovery process,and participants are divided into two groups to ensure that if the number of participants in any group is not enough,the secret can not be recovered.Therefore,it meets the need of two groups of participants to share secrets.At the same time,sub-secrets are distributed to participants in the form of vectors,which reduces the loss caused by the loss of sub-secrets.The analysis and comparison show that the scheme has lower risk and higher anti-collusion ability than the scheme based on univariate polynomial,so the security of the scheme is higher.(2)Considering multi-secret sharing and possible attacks and deceptions in schemes,based on the threshold scheme based on bivariate Lagrange interpolation polynomial,a threshold multi-secret sharing scheme based on bivariate Lagrange interpolation polynomial is proposed.In this scheme,the sub-secrets of participants are chosen by themselves,and these sub-secrets are random and reusable.By using trapdoor one-way function,two-variable one-way function and the difficulty of discrete logarithm over finite fields,it is possible to effectively protect sub-secrets,verify pseudo-shadows,and reduce system implementation costs.The analysis and comparison show that the scheme can prevent outsiders from illegally obtaining sub-secrets and pseudo-shares,and it can also prevent the cheating of insiders.At the same time,the scheme has stronger anti-collusion capabilities and lower success rate of exhaustion than the multi-secret sharing scheme based on univariate polynomial.So it has higher security and it is suitable for secure cloud storage of data.(3)Facing the situation of user data leakage in cloud storage,it is necessary to adopt a reasonable way to manage the key on the basis of encryption.Based on the multi-secret sharing scheme in this paper and Hadoop cloud platform,a secure cloud storage scheme based on secret sharing is proposed.Firstly,the key is divided into multiple secrets.And then the threshold multi-secret sharing scheme based on bivariate Lagrange interpolation polynomial is used to share the multiple secrets.Finally,the ciphertext and the pseudo-shadows are uploaded to the cloud through the file writing process.The multi-layer authentication of the accessing user is realized by using the security authentication mechanism in Hadoop.Only users who pass all the authentications can obtain the ciphertext and a sufficient number of pseudo-shadows through the file reading process,thereby recovering the key and the plaintext in turn.The security analysis shows that the scheme can effectively ensure the reasonable management of the key,thus ensuring the security of user data and realizing the secure cloud storage of data.