Partial policy hidden medical data access control method based on CP-ABE

The secure sharing and privacy protection of medical data are of great significance during the development of smart medical care. In order to achieve data sharing among medical institutions, ciphertext-policy attribute-based encryption (CP-ABE), a potential technology, allows users to encrypt data under access policies which are defined on certain attributes of the data consumer, and only allows the data consumer to decrypt those attributes conforming to the access policy. However, some existing CP-ABE schemes still have some shortcomings. For example, the efficiency of encryption and decryption is not high enough, and some cannot support more sufficient and expressive access structures. To solve the above problems, combined with blockchain, this paper presents a CP-ABE scheme with partial policy hiding based on prime order bilinear groups. Extensive experiment and analysis results reveal that the proposed scheme protects the privacy of users and realizes that attribute values are hidden in the access policy.