Research On Attribute-based Encryption Scheme For Keyword Searchable And Attribute Revocable In Cloud Storage

With the development of outsourced data services in recent years,how to protect data security has become an urgent problem to be solved.The attribute-based encryption is an effective solution to data security in cloud storage and can achieves fine-grained access control of data.The keyword search based on attribute encryption can ensure that the owner grants search capabilities to users,but most schemes cannot guarantee the privacy of the access structure.In practice,the single-authority encryption schemes have the disadvantages such as low efficiency and low security et al.Consequently,our proposal mainly studies the attribute-based encryption of keyword searchable and attribute revocable on cloud storage.The main research results are as follows:We propose a hidden access policy scheme for attribute-based encryption of keyword searchable and attribute revocable on cloud storage.The keyword index and ciphertext encryption use the same access control.The advantage of embedding access control in the keyword index is that as long as the user's attributes satisfy the access control,the searching data can be decrypted by the user.In this way,we improve the accuracy of the search data.At the same time,both ciphertext and keyword index achieve the protection of user privacy through hiding access policy.The new scheme has the function of attribute revocation,which is suitable for the actual situation where the user's attribute changes.Afterwards,under the general bilinear group model,we demonstrate the security of the scheme and analyze the efficiency.We construct a multi-authority keyword searchable attribute-based encryption scheme with limited access time.The multi-authority encryption is more secure and efficient.In the keyword search phase,the time server is embedded in the scheme.When the user's effective time is not within the set value range or the user's time automatically expires,which will not be able to execute search operation,and the attribute revocation will not make more changes.The decryption phase adopts outsourced decryption technology and divides the private key into two parts.The cloud server is responsible for the part with a large amount of computation,which reduces the computational burden of the user,but does not leakage any data information.Finally,the security of our scheme is based on hard assumption.