Multi keyword searchable attribute based encryption for efficient retrieval of health Records in Cloud

Personal Health Record (PHR) is an online electronic application used by patients to store, retrieve and share their health information in a private and secure environment. While outsourcing the PHR into cloud environment, there exist issues in privacy while storing, searching and sharing of health information. To overcome these issues, an efficient retrieval of health records using Multi Keyword Searchable Attribute Based Encryption (MK-SABE) is proposed. To manage the increasing PHR data in the cloud, an Authorized File Level Deduplication technique is adopted. It eliminates redundant files, thereby reducing the communication overhead. Moreover, PHR data is encrypted before outsourcing and to perform searching over encrypted data, the proposed MK-SABE introduces Conjunctive Multi Keyword Searchable Attribute Based Encryption (CM-SABE). This maintains the searchable property after encryption for efficient retrieval of health files using range query. Further to ensure the trustworthiness while sharing the sensitive data, MK-SABE introduces the Location Based Encryption (LBE) and Dynamic Location Based ReEncryption (DLBRE) technique to provide additional security. From the experimental analysis, it is proved that the proposed MK-SABE reduces the storage complexity by 5%, keyword search time by 25% and improves the overall performance of PHR by 40% compared to the existing schemes.