Abstract:  In order to realize fine-grained access control, secure storage and sharing of electronic health record data, this paper proposes a cloud-chain collaborative storage electronic health record sharing scheme based on attribute encryption. In the scheme, the symmetric encryption algorithm is used to encrypt the electronic health record, the ciphertext-policy attribute-based encryption is used to encrypt the symmetric key, and the searchable encryption algorithm is used to encrypt the key words. Electronic health record ciphertext is stored on the medical cloud, and secure index is stored on the consortium chain. The secure search of keywords is realized by the searchable encryption technology and the user attribute is relocated by proxy re-encryption technology. It is proved that the scheme can achieve the security of ciphertext and keyword. The numerical simulation results show that the scheme is effective.

Key words: electronic health record, consortium blockchain, searchable encryption, proxy re-encryption, attribute-based encryption, attribute revocation