Due to the proliferation of cryptocurrencies and decentralized apps, blockchain has recently sparked widespread attention and worry. It functions as a database and is used to keep track of a huge number of entries in a time-ordered fashion for use in data-heavy applications. It is proposed in such a scenario that search engines be used to retrieve the data stored in a blockchain and then analysed for various reasons. However, there hasn't been any comprehensive study of blockchain search engines yet, and the field is still in its infancy. Both the present state of blockchain search engine development and its potential in the Internet of Things (IoT) space are examined in this article. The paper's primary focus, from a research standpoint, is on the categorization of blockchain search engine techniques and a comparison of their relative performance. Current search works connected to IoT domains are introduced with the future potential of blockchain search engines in this space. The remainder of the paper provides a history of blockchain technology. Then, the search necessities are laid down, such as the basic rules of categorization. We then provide a problem analysis of blockchain search in IoT domains and a comprehensive overview of previous work in this area. We conclude with a discussion of the difficulties inherent in blockchain-based searches and an outlook for future research initiatives in IoT-related fields.

Blockchain search engine Search fundamentals Search requirements