An Efficient Consortium Blockchain Dual Privacy Protection Scheme

The ledger on the blockchain is public, so that the transactions on the chain can be verified and traced by other nodes, but it will also lead to the privacy of blockchain users being leaked or analyzed by some malicious users to learn their true identities. Therefore, this paper suggests a privacy preserving scheme based on verifiability certificateless ring signatures and homomorphic encryption to solve privacy concerns in consortium blockchain. Firstly, the certificateless ring signature based on elliptic curve is improved to increase the verifiability to prevent malicious users from using the unconditional anonymity of ring signature to perform some malicious acts. In the meantime, the certificateless cryptosystem has the advantages of keyless escrow and high security, which can make our entire solution more secure. Secondly, the transaction amount is encrypted with homomorphic encryption where the data is available but not visible, which protects the privacy of the transaction amount while facilitating subsequent verification. Finally, it is analyzed and compared with other schemes, which proves that the scheme has certain advantages in terms of efficiency while protecting double privacy.