Abstract:

In view of the defect that blockchain cannot meet the requirements of large-capacity medical data storage such as video and audio, this paper adopted the multi-cloud and multi-chain collaborative mode to share medical data safely. In order to prevent proliferation and leakage, an identity multi-anonymization method was proposed to anonymously store medical data encrypted by hospital’s public key in a private cloud. Based on the multi-chains distinguishing record method, the projection will be extracted and packaged on the corresponding blockchain in terms of the patient’s medical service type. To avoid the hijacking of hospital miner server, the trust value is evaluated according to the relevant blockchain, so as to fight against the diverse miners behaviors (DMB) attacks that may exist in the multi-chains consensus. A confidentiality relay access control protocol is designed to achieve the security of medical data sharing among alliance users without direct access. Security analysis and simulation results show that this scheme can effectively prevent the leakage of patient identity privacy, the theft and tampering of medical data. Meanwhile, the accuracy of consensus can be guaranteed at a lower cost.

Key words: cloud storage, blockchain, medical data, DMB attack, security sharing