On December 7, the "Blockchain Technology and Application" Science and Technology Frontier Forum hosted by the Chinese Academy of Sciences and jointly supported by the China Academy of Information and Communication Technology was held in Shenzhen. Tang Shaohua, a professor at South China University of Technology, a Zhujiang scholar, a leader in the Special Support Program, and director of the Guangdong Information Security Engineering Technology Research Center, said that there will actually be some privacy issues in smart contracts. When a smart contract is used, some privacy in its input and output, calculation process, and calculation results may be leaked, and the privacy of the code of the smart contract may also be leaked. The technical methods for solving the privacy calculation of smart contracts mainly include some technologies in cryptography, including zero-knowledge proof, secure multiparty computing, trusted computing environment, and so on. Tang Shaohua finally emphasized the issues of privacy protection and supervisability: "We cannot strengthen privacy protection to make the blockchain a paradise for criminals. Zero-knowledge proofs protect users' identity privacy. Secure multi-party computing protects the privacy of contract data. Trust the computing environment to ensure the privacy of the contract code, and pay special attention to the combination of security chips and blockchain. "