Abstract: Block chain is a distributed database with the characteristics of decentralization, joint supervision and tamper proof. However, the decentralization and high transparency of the block chain lead to the disclosure and leakage of traders' private data, and the security of traders' private information is not guaranteed. Therefore, the issue of block chain privacy protection is also the focus and difficulty of block chain data security research. In recent years, many block chain privacy protection schemes based on zero knowledge proof technology are proposed, but there are still many demerits for different application scenarios. Aiming at the problems of privacy protection in block chain applications, the existing algorithm technology based on zero knowledge proof technology are elaborated and summarized, and then privacy protection scheme based on zero knowledge proof technology are analyzed and elaborated. Finally, in view of the demerit of the existing block chain privacy protection, the focus of future research is summarized and the direction for future research work is pointed out.

Key words: block chain, privacy protection, zero knowledge proof, cryptography, information safety