Abstract: Similar to Bitcoin,Monero is also a cryptocurrency.The original Monero is based on the CryptoNote protocol,which uses ring signatures and one-time keys to hide the real identities of both parties to the transaction,but the specific transaction amount is exposed in the area.In the blockchain,there are certain security risks.To address this security hole,Shen Noether proposed ring confidential transactions(RingCT),which utilizes a random number to hide the real transaction amount.The ring confidential transaction protocol currently uses by the Monero community is based on the discrete logarithm problem.However,with the development of quantum computers,solutions based on traditional number theory problems will become no longer secure.Post-quantum solutions are a good alternative.Multivariate public key cryptography is one of the main research directions of post-quantum cryptography,and compared with other post-quantum cryptographic schemes,multivariate-based signature schemes tend to have faster computing speed and less computing resources in the process of signature and verification.It has good researchva-lue.Based on the multivariable ring signature scheme,this paper designs a multivariable ring confidential transaction protocol.The protocol uses the additive homomorphism of the public key of the multivariable signature scheme to realize the commitment to the transaction amount,and performs a ring signature on the commitment.By randomly selecting the user public key in the blockchain to form a ring,the identity of the actual transaction participants in the transaction is confused.At the same time,during the transaction generation process,the trader’s private key will be used to generate a unique key-image,and it will participate in the signature generation process and become a part of the signature.By comparing this part,the transaction double-spending can be effectively prevented.The security of the proposed scheme is proved in the random oracle model,and compared with the lattice-based post-quantum secure ring confidential transaction protocol,the proposed scheme has more advantages in signature efficiency and verification efficiency.

Key words: Multivariate public-key cryptosystem, Post-quantum, Ring signature, Ring confidential transactions protocol, Homomorphic commitment