Data access control method and system in cloud storage environment

Embodiments of the invention provide a data access control method and system in a cloud storage environment. The method mainly comprises the steps that a user registers personal information to a cloud server through a client side; when a data owner determines that the data to be transmitted to the cloud server is shared data, the client side of the data owner uses a symmetric key to encrypt the data, and sends the encrypted data, the symmetrical key, a hash operation result of the data and a shared attribute of the data to the cloud server; when the data is not the shared data, the client side of the data owner uses its own public key to encrypt the data, and sends the encrypted data, the hash operation result of the data and the shared attribute of the data to the cloud server. Through adoption of the method and system, confidentiality and integrity of the user data are guaranteed, and confidentiality of the user files is classified, so that authority control under data sharing is better realized, and security improvement of data access control under cloud storage is effectively provided.