Attribute-based encryption schema with group signatures

Cipher text-policy attribute-based encryption schema(CP-ABE) is widely used in protection of sensitive data. In CP-ABE, When the users access the cipher text, the access structure and the cipher text were sent to the users. However, the access structure is also has private information which can lead to leak of the privacy. The group signatures were used in CP-ABE to realize protection of the privacy.What’s more, it can satisfy indistinguishable under the choice of plaintext attack.