Privacy-Preserving and Blockchain Blockchain has recently received a vast amount of attention from the computer scientist to use it in various applications in different real-world applications and systems, especially because of the distributed nature and decentralized data in almost every computer system. On the other hand, preserving the privacy of data has been always a challenging issue in many fields that are dealing with sensitive information, such as health sector, government, and business. Recent research shows that in one side we can propose privacy-preserving protocols for the systems that use blockchain, while the blockchain itself can also be used to preserve privacy in some applications. In this research project, we are going to perform a comprehensive survey and literature review on blockchain technology and its current status in different fields of applications. Then, we investigate on how Blockchain could be used for preserving data privacy, and on the other hand how we can apply privacy-preserving approach on the systems that use blockchain.