Any online transaction that consists of digital money is a piece of a challenge these days with the growing threats of hackers looking to steal bank info posted online. This leads to the invention of various kinds of crypto-currency money, Bitcoin is one of them. The generation behind the usage of Bitcoin is popularly referred to as BLOCKCHAIN.

Nowadays Blockchain has become a buzzword in both industry and academia. Blockchain is a constantly developing ledger that keeps a permanent document of all the transactions that have taken region in a relaxed, chronological, and immutable way. It is able to be used for the comfy transfer of cash, belongings, contracts, and so forth. Without requiring a 3rd- party intermediary such that a financial institution or government. Blockchain is a software protocol however it couldn’t be run without the net (like SMTP is for electronic mail).

It is a distributed database of information or in other words, it is a public ledger (files) of all transactions done in the online world. The Blockchain is innovation and a strategy that permits local area clients to approve, keep and synchronize the substance of an exchange record which is duplicated across numerous clients.

In the academic field, blockchain technology is also attracting more and more attention. The study of blockchain can be divided into three categories. Firstly, study on the digital currency that is based on blockchain, including the decentralized and centralized digital currency [4]. Secondly, study on the application of blockchain technology in non-digital currency scenarios such as the application of blockchain in smart cities [5] and medical information security management [6, 7]. Thirdly, study underlying blockchain technology. More and more researchers realize that the blockchain can be stripped out from digital currency to create a revolutionary technical architecture in other areas. Some researchers have begun to study the underlying technologies such as the difficult control of mining [8], the scalability of consensus algorithms [9] and the smart contract [10].