Improved Searchable Attribute Based Encryption in Cloud

The development of online electronic personal data leads to the trend that data owners prefer to remotely outsource their health information to the cloud. Personal Health Record (PHR) is a developing online service model that allows PHR users to enjoy high quality retrieval of health record and storage space. However, an efficient secured share and search for the outsourced health data is a difficult task. Searchable Attribute Based Encryption (SABE) enables the data owners to efficiently share his/her data to a specified group of users. It requires the health data to preserve its searchable property while it is shared among public domain users like doctors and researchers. Moreover, it facilitates keyword search on ciphertext which consumes a considerable amount of search time in keyword query processing. To minimize the search time to retrieve the related health attributes from PHR database, this paper proposes an Improved SABE (ISABE) for PHR in the cloud. Nowadays, Global Positioning Service (GPS) is combined with mobile technology and it became part and parcel of our lives. However, most of the existing crypto-graphic schemes are location independent. Therefore, Location Based Encryption (LBE) allows a secure communication of mobile nodes by restricting unauthorized access of sensitive information at a specific location and time. But the existing GPS technology has several inconsistencies like the triangular problem and number of keys generated for the particular user within the region of interest. To minimize the number of keys generated for the mobile users in an environment with location based services, this paper proposes an Enhanced Location Based Encryption (ELBE) with threshold limit to enforce non repudiation. From the experimental results, it is found that the proposed ISABE with ELBE improves the efficiency of the PHR system in the cloud by minimizing the storage complexity, keyword query search time and Key management for PHR users in a multi owner cloud environment.