Verifiable and Revocable Attribute Encryption Scheme Based on Blockchain
In view of the issues of privacy leakage and user rights management in data sharing in electronic medical systems,and the fact that cloud storage servers may return incomplete and incorrect ciphertext results,this paper proposed a verifiable and revocable attribute encryption scheme based on blockchain.This solution used ciphertext-policy attribute-based encryption technology to ensure the confidentiality of shared data in the electronic medical record system and achieve fine-grained access control of private data.At the same time,a user revocation algorithm was designed using the chameleon hash function so that unauthorized users cannot continue to access shared data.In addition,a result verification algorithm was designed using a cryptographic accumulator,which was executed by a smart contract deployed on the blockchain to ensure the correctness and integrity of the data returned to the user by the cloud server.In terms of security,it is proved that the ciphertext information of this scheme was indistinguishable under a chosen plaintext attack.Finally,the JPBC cryptographic library and Hyperledger Fabric blockchain platform were used to simulate the scheme proposed in this article and similar schemes.The results show that this scheme has high computational efficiency in the key generation,encryption,decryption and user revocation stages.
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