Study On Attribute Based Encryption Of Cloud Storage

With the rapid development of information and Internet technology, a new Internet service called “cloud computing” is put forward, the purpose of which is to to solve the increasing amount of Internet information. According to the survey, the amount of information on the Internet increases exponentially, and in this context, the data should be stored in a better way. Based on the cloud computing, a new cloud service(i.e. cloud storage)is proposed to provide users with an on-demand services for storage, the storage device of which is associated by some software on the Internet.While the cloud storage produces large cost savings for users and business, data security increasingly becomes the focus of attention. Because service providers of cloud storage is not completely credible, people want to protect the security of data by encryption and access control technology. As the traditional access control is not as flexible as the access control based on attribute, the traditional symmetric encryption system is very difficult in the distribution of key, and the asymmetric encryption system needs to store multiple copies of the ciphertext, cloud storage based on attribute encryption system and access control has become a hot spot of research on cloud storage security.The access control scheme of cloud storage is mainly based on ciphertext policy attribute based encryption(CP-ABE). The early access control system of cloud storage only have a single authority and this makes the authority a bottleneck of data security. In order to increase the data security, some experts propose a multi authority CP-ABE scheme, but when attribute is cancelled, the scheme needs to update all customer codes, which increases the computational cost of the system. By adding attribute revocation list to authority and combining re-encryption technology with decryption outsourcing technology, an effective attribute-revocation based on forward and backward security is achieved, which reduces the computational overhead of authority as attribute is cancelled.