Efficient Compressed Ciphertext Length Scheme Using Multi-Authority CP-ABE for Hierarchical Attributes

In an attribute-based encryption, the user is identified with help of some attributes and their functions for encryption and decryption of the data. The current techniques based on attribute-based encryption have found that if user's access structure includes a considerable amount of attribute information labeled as Don't Care, then the encryption pairing operation has low calculation efficiency and ciphertext information redundancy. In this paper, we have proposed a hierarchical multi-authority attribute-based encryption on prime order groups to tackle these problems. Our encryption technique has a polycentric attribute authorization system based on an AND gate access structure, with a unified attribute index established by each attribute authority throughout the system, to form a binary tree, i.e., attribute access tree. The state value of the parent node can be determined by the state of its child node in an attribute access tree. The attribute-based encryption established in this manner is theoretically proven to effectively decrease the calculation amount for decryption and compress the redundant information in the ciphertext as much as possible. Our encryption technique has a theoretical and practical significance in the system of "large universe"constructions.