关键词: 关键词：非交互零知识证明, ElGamal算法, 默克尔树, 身份认证

Abstract: Due to the rise of cryptocurrencies underpinned by blockchain and cryptography， the traditional centralized transaction model has been broken. But while it brings many conveniences， it also exposes flaws. When the user key of the cryptocurrency is lost or an attacker exploits the contract vulnerability to illegally transfer funds， the system lacks additional authentication and fund custody functions， which will cause the user to lose control of the funds. In view of these problems, the proposed proposal will write the user’s account fund tracking management rules into the smart contract, and force the user to call the two-factor authentication scheme （combined with non-interactive zero-knowledge proof， Merkle tree， ElGamal algorithm and other methods） to verify the legal identity and prevent attackers from illegally transferring funds under specific abnormal circumstances. The results of comparison with other schemes show that the scheme has a certain improvement in safety and efficiency.

Key words: Key words: NIZK, ElGamal algorithm, Merkle tree, identity authentication