Research On Correct Possession Checking Of The User Data In Cloud

With the continuous development of cloud storage services,user data storage has been transferred from the local server to the cloud environment.With this change,users lose the direct control of data,which brings challenges to the data security of users.In order to gain more benefits,cloud service providers may illegally transfer user data to storage devices with lower maintenance costs,or even delete some data to save storage overhead.Therefore,it is necessary to ensure that the user data is stored in the specified geographic location.This paper analyzes the security problems faced by cloud storage services,and focuses on ensuring the standardization of cloud storage server's geographic location and the possession of user's data.In this paper,the weighted centroid algorithm and delay measurement are combined to design a cloud server location scheme.The RSA homomorphic property and security location protocol(SLP)are combined to design a cloud data correct possession verification scheme.The specific work is as follows:The location scheme based on existing time-delay measurement ignores the impact of time-delay fluctuation.This paper proposes a location scheme based on weighted centroid estimation,which combines with the delay measurement and the weighted centroid algorithm effectively.In this scheme,the deployed landmark nodes are used to measure the delay of cloud sever location.The scheme analyzes the fluctuation degree of the measured delay data,and gives a smaller weight to the data with larger fluctuation amplitude,which can reduce the impact of the delay fluctuation amplitude wave on the positioning accuracy.This scheme establishes the mathematical relationship between the time delay and the geographical distance,abstractes the geographic location of the cloud server as the intersection area of the two-dimensional coordinate plane.This scheme calculates the centroid of the intersection area,and then gets the location of the cloud server to be located.The experimental results show that the scheme can achieve the maximum positioning accuracy when the number of landmark nodes are 30,and can meet the regional level positioning accuracy requirements.Because the cloud storage service provider may have the behavior of forging the geographic location or not possess correct data,this paper,SLP protocol and RSA homomorphism are combined to propose a scheme to verify the correct possession of cloud data.The scheme builds a model of cloud data correct possession verification system,analyses the possible adversary attacks,and gives the security target of the scheme.In the initialization stage,user generates the RSA public-private key pairs,calculates the data label,that is,the possession evidence.Then,the data file are encrypted by private key and uploaded to the cloud server together.In the verification stage,the cloud server calculates the possession evidence and returns it to the verifier according to the challenge initiated by the trusted third-party verifier.The verifier uses SLP protocol to verify whether the cloud service provider forges the geographic location,and returns the possession evidence to the user through the secure channel.The user determines whether cloud service providers possess intact data according to RSA homomorphism.Through the security analysis,we can see that the scheme can defend the attack such as the enemy's delay sending data,and meet the security target of the scheme.