We propose a new large-universe multi-authority ciphertext-policy attribute-based encryption system. In this system, any string can be used as an attribute of the system, and there are several authorities, each of which is responsible for the authorized key distribution of a specific set of attributes. Then, we prove its security under two static assumptions without random oracle. The main techniques used in this work are "Waters' hash" over global identifier and attribute information in the construction, as well as dual system encryption in the security proof. To the best of our knowledge, this is the first ciphertext-policy attribute-based encryption system satisfying both of "large-universe" property and "multi-authority" property without random oracle. Finally, as the application of our new scheme, we propose a new data access control scheme for cloud storage systems.
['Hao Wang', 'Zhihua Zheng', 'Lei Wu', 'Debiao He']
New large-universe multi-authority ciphertext-policy ABE scheme and its application in cloud storage systems