Abstract:Cloud storage is the future development direction of the storage business, and data security is the primary concern of cloud storage customers. The Ciphertext-Policy Attribute-Based Encryption (CP-ABE) algorithm allows the data owner to embed the access policy in the ciphertext and implement access control in conjunction with the key of data accessor, which is particularly appropriate for cloud storage environments. However, CP-ABE does not support time-related access control. This study proposes a CP-ABE scheme based on Time-Release Encryption (TRE). By incorporating a TRE mechanism in CP-ABE to achieve ciphertext sharing with time control, this scheme allows data owners to formulate a more flexible access strategy based on user attributes and access time. And then, we conduct security analysis to verify that this scheme can resist illegal access from users, cloud storage platforms and authorized institutions, as well as collusion attacks of illegal users. In addition, this scheme can also resist chosen-plaintext attack.