Blockchain data sharing scheme based on quantum re-encryption.

The current blockchain systems lack the ability to resist quantum computing attacks. This puts the confidentiality and integrity of data in blockchain-based data sharing at risk. The security of data sharing faces the new challenges. In this paper, a blockchain data sharing scheme based on quantum re-encryption is proposed. The presented scheme uses quantum key and unitary matrix to encrypt data for two times. It ensures data sharing between the data owner and the data accessor without revealing the owner's private key. Moreover, it utilizes a quantum hash function based on controlled alternate quantum walks to compute quantum hash value. The obtained hash value has higher randomness, collision resistance and input sensitivity. Additionally, this method combines on-chain and off-chain storage. The combined storage method effectively alleviates the storage pressure on the blockchain. Finally, the security of the proposed scheme is analyzed. The results show that this scheme ensures the integrity, confidentiality and non-tampering of the shared data. At the same time, it protects the security of data owner's private keys. [ABSTRACT FROM AUTHOR]