Abstract: In traditional blockchain transactions,privacy protection is to encrypt users' sensitive information under the anonymity mechanism,and a trusted third party is involved to verify the transaction plaintext information.However,once the third party is attacked,the users' transaction information will be divulged.Furthermore,there is no truly trusted third party in a rational state.To better solve the privacy problems in blockchain transactions,and in view of issues of confidentiality verification of the tra-ders' transaction amount under the non-anonymous state,the PVC digital commitment protocol is adopted to hide the transaction amount in the commitment,and a publicly verifiable zero-knowledge proof scheme is established,so that verifiers are able to confidentially verify the legitimacy of the transaction without obtaining sensitive information from the traders.At the same time,the elliptic curve homomorphic encryption feature is used to encrypt the amount,thereby solving the problem of updating the traders' ciphertext ledger.The correctness of the proposed privacy protection scheme is verified and analyzed,and the results shows that compared with the existing schemes,the proposed scheme has the advantages of relatively low computational complexity,strong security and high efficiency.

Key words: Blockchain, Confidentiality verification, Elliptic curve homomorphic encryption, Publicly verifiable, PVC digital commitment