An Overview
In today's digital world, there is an immense growth of data which is difficult for the users to store and share it locally. Due to this, a greater number of users switch to cloud storing facilities. But somehow, the data stored in the cloud might be manipulated or lost due to the unavoidable software bugs, hardware flaws and human inaccuracy in the cloud. In order to check whether the data is stored accurately in the cloud storage, many remote data integrity auditing schemes have been implemented.
The data stored in the cloud storages is frequently shared across multiple users in other cloud storage applications, such as Google Drive, Dropbox and iCloud. Data sharing in cloud storage allows a number of users to share their data with others. However, shared data in the cloud platforms might contain some tactful or sensitive information. For example, the Health Records, Bank Transactions, Confidential information etc. stored and shared in the cloud usually contains tactful or sensitive information. If these documents are directly uploaded to the cloud to be shared for research purposes, the sensitive information of data owner will be inevitably released to the cloud and the researchers. Thus, it is important to achieve remote data integrity auditing on the terms that the sensitive information of shared data is protected. A typical method of solving this problem is to encrypt the whole shared file before sending it to the cloud storages, and then verify the integrity of this encrypted file. This method provides the sensitive information hiding since only the data owner can decrypt this file. But, the whole shared file will be will not be available others. For example, encrypting the Health Records of infectious disease to patients can protect the privacy of patient and hospital, but this encrypted Health Record cannot be efficiently used by researchers for further findings any more. Distributing the decryption method to the researchers seems to be a possible solution to the above problem. However, it is impractical to accept this method in real scenarios due to the following reasons.
Firstly, distributing decryption method needs secure sources of communication, which is difficult to be implemented for each researcher in some instances. Further, it seems very hard for a user to know which researchers will use his/her Health Records in the near future when he/she uploads the Health Records to the cloud. As a conclusion, it is impractical to hide sensitive information by encrypting the whole shared file. Thus, how to execute data storing and sharing simultaneously with sensitive information hiding in remote data integrity auditing is very dominant and valuable.