As a decentralized distributed ledger, blockchain has developed rapidly since its birth and has been highly valued by governments, academia, and industry. Start in the financial field, blockchain technology has been rapidly applied to various fields such as the Internet of Things, supply chain, and healthcare. Blockchain technology has made sufficient development and innovation, but it also faces many challenges, such as security, scalability, and waste of resources. This paper starts with the development history of blockchain and combines the characteristics and technical principles of it to analyze the current academic research status and application scenarios. Meanwhile, this paper analyzes the existing outstanding blockchain projects and elaborates on their key advantages and current challenges. With discussing the ongoing development trend of blockchain, the development direction, and the research trend of blockchain in the future, this paper provides a useful reference for related research.

For the past few years, Internet of Things (IoT) has developed rapidly and been extensively used. However, its transmission security and privacy protection are insufficient, which limits the development of IoT to a certain extent. As a technology of IoT information transmission, anonymous communication technology comes into being as an important means to ensure the security of healthcare data, which can better protect users’ privacy in some ways. Nowadays, a variety of attack techniques for anonymous communication systems have been proposed by the academic community to track senders and receivers or discover communications between two users. Thus, the MSFA (Multiple System Fingerprint Attack) scheme for anonymous communication systems is presented in this paper where the MSFA scheme architecture, implementation in the Tor environment, and experimental data processing are described. Through a comparative analysis between two traces of visiting the same website based on the edit distance, it is shown that the longer the length of the site traffic data, the greater the edit distance of the site access traffic and the larger the range.