Most people have witnessed the craziness of surrounding the Bitcoin. Some predict that Bitcoin can be replacing both nominal currency and gold as a means of value storage or transaction payment, and that limited supply can lead to astronomical value. This article will explain blockchain, a technology that supports Bitcoin easily, so you can establish your own opinion on how revolutionary this technology is. Then, what is so special about blockchain? Why do the clearest people, including many CEOs of large corporations, believe that the blockchain has tremendous potential to change the world, and investment in developing this technology continues to grow? If you look at the blockchain as a publicly shared database among many participants, you can easily understand the concept (but blockchain technology can be built privately to restrict access). Each participant connects to this network through a computer, and all participants maintain the same copy of the database. Therefore, one of the key basic principles of the blockchain is that the information is transparent and can be used by all participants in the network at the same time. Bitcoin is probably one of the most well-known public blockchains. Bitcoin provides users with digital currency that can pay for goods and services or act as a value store like ordinary currency based on blockchain technology. It is open to the public and anyone can participate in the Bitcoin network.