Block chain is a distributed ledger technology that creates a network that is difficult to destroy or tamper with without distributing centralized computers by distributing data to computer scattered throughout the world. Originally, it was an idea created by ""Satoshi Nakamoto"" which is called as the inventor as a basic technology supporting bit coin (Bitcoin), and today, among unspecified number of participants without mutual trust, Since it is suitable for realizing the transfer of rights, it can be applied to a wide range of fields. In general, block chains have characteristics that it is extremely difficult to destroy or tamper with conventional centralized control systems, and that they can construct a system that is substantially zero downtime at low cost, and now, in the financial field Is expected as one of the core technologies of ""FInTech (FinTech)"". Block chain is a distributed computer network that everyone can monitor, it is a technology that enables a way to reach a credible consensus without centralization. In addition, the name comes from a mechanism that adds to the existing record (block) one after another in the form of a chain when adding new records. The following are the basic features of the block chain: · Information is communicated via a networked computer and shared widely. · Every time information passes through, it is checked by the computer and all information is accumulated (recorded) as a chain of data having time series information called a block. · The recorded information is structured such that no one can forge or alter, and the safety of the transaction is secured. · Since the core of the system is dispersed all over the world, destruction is difficult (impossible), no one can stop spreading.