5、bstractAbstractWith the popularity of the Internet, cloud computing technology has been developed rapidly.Cloud storage isa derivative of cloud computing, and it won people's favoritewith the advantages of low cost and easy to extend. However, the frequent security incidents makemany users do not wa
6、nt to store their sensitive data in the cloud storage. Access control mechanism can effectively solve the problem. The attribute-based encryptionis more suitable for cloud storage access control because of its ability to achieve one to many cryptograph sharing.However,the current attribute-based enc
7、ryptionhas some problemswhen the access policy changes andthe ciphertextlocal changes. Therefore, the flexible and efficient access control mechanism in cloud storage has become the focus.In this pape