Controlling decryption of personal health records in the cloud

Abstract

For personal health record storage systems in the cloud where the information must be encrypted before storage, we propose splitting the decryption key into two parts, where the user owns one part that is called an ownership code or a right-to-decrypt code, while the other part, called a substitute-key-half code, is stored in the system. The decryption key can only be recovered using these two separate secret parts, and the information stored in the system will not disclose any clues that could lead to guessing the decryption key, thus strengthening information protection and ensuring that the personal health records will not be disclosed to anyone without authorization.