Efficient and Privacy-Preserving Medical Data Sharing in Internet of Things With Limited Computing Power

With the application of Internet of Things (IoT) technologies in smart city, intelligent medical terminals play a more and more significant role in our daily life. These terminals can monitor our physical conditions and get lots of medical data in time. For the sake of data security and practicality, the collected big data can be encrypted and then stored on a cloud server such that only authorized users, such as the data owner and the doctors, can access. However, smart terminals are usually limited in computing power and users' privacy issues remain. To tackle this challenging problem, an efficient medical data sharing scheme is presented in this paper. To solve the privacy issues in users' data sharing, we utilize attribute-based encryption to enable data sharing. In addition, we remove the attribute matching function and use the attribute bloom filter to hide all the attributes in the access control structure. In order to improve the efficiency of encryption, we introduce the online/offline encryption technology in the encryption phase. Before the message is known, a large amount of work that is needed at the encryption stage will be done. Then, once the message is known, the ciphertext can be generated quickly. Besides, the initialization stage of the system does not need to specify all attributes. When the overall attributes of the system users increase, the system does not need to be reinitialized, which will also improve the system efficiency. Security analysis and performance analysis show that the data sharing scheme is secure and can improve data processing ability in IoT based data sharing.