An Efficient Encryption Scheme with Fully Hidden Access Policy for Medical Data

Abstract

With the development of informatization, patient medical data are generally stored in the form of electronic medical records. Hospitals store a large amount of medical data on cloud servers, which can ensure the integrity and sharing of medical data. There are many problems when sharing medical data, the most important of which is the security of private data. The ciphertext-policy attribute-based encryption (CP-ABE) algorithm not only supports data encryption, but also supports data access control. The CP-ABE algorithm is applied to medical databases. Through the encryption of medical data and the fine-grained control of data owner access to medical data, the privacy security and sharing security of medical data are realized. However, the traditional CP-ABE algorithm also has problems for the data user regarding access policy privacy leakage and the low efficiency of medical data encryption and decryption. This paper proposes a secure and efficient encryption technique. Medical data are encrypted using a symmetric encryption algorithm, and the CP-ABE algorithm with a fully hidden access policy encrypts the symmetric key. To implement access policy hiding, it uses an attribute bloom filter (ABF) for all access structures. The solution also supports the outsourced decryption of medical data, which can improve the encryption and decryption efficiency of the technique. Finally, in this paper, it is demonstrated that the scheme is selectively chosen-plaintext attack secure (CPA-secure). The experimental results show that users have less computational consumption to obtain medical data.