Secure medical data sharing scheme based on traceable ring signature and blockchain

In order to solve the problem of medical data sharing difficulties among medical institutions, we propose a secure medical data sharing scheme based on traceable ring signature and blockchain. Firstly, a certificateless traceable ring signature algorithm based on distributed key generation is proposed to provide data integrity with privacy preservation. Secondly, the smart contract combined with access control and Self-Controlling Object (SCO) can realize the decryption outsourcing and data sharing. In addition, the proposed scheme uses the InterPlanetary File System (IPFS) to store the oceans of medical privacy data, and encrypts the hash index to store, which improves the efficiency of data sharing. Finally, integrated with the blockchain, we can select the proxy node and upload the SCO package to the blockchain node for data sharing by using consensus mechanism. The security analysis shows that the scheme can realize the electronic health record (EHR) source tracking while achieving secure data sharing and privacy protection. In the performance evaluation, we compare the functionality with other schemes and conclude that our scheme is well-functional. Also, the time-consuming simulation of the algorithms in our scheme using the PBC library reflects a high practicality. The results show that the proposed scheme is secure in terms of medical data sharing and privacy protection, and feasible for data source tracking.