The blockchain is a technology. This technology is currently adopted in cryptocurrencies. This blockchain can be otherwise termed as a ledger or a list of record of accounts, which is ever growing in size. The blockchain is composed of blocks. These blocks are records of accounts. These blocks are secured and linked together, in a chain by cryptographical methodology. Technically, a blockchain can be termed as the leading software platform in the world for those assets, which are digital in nature. Every block in a blockchain carries a cryptographic hash of the block before it, the data for transactions and a time stamp. The blockchain is essentially so designed that the data within can never be modified. The blockchain is an open ledger that is publicly distributed. Blockchain efficiently records all transaction made in cryptocurrencies by two parties. This record is a permanent record and can be verified. When a data is recorded in the block, the data can never be altered unless all subsequent blocks are altered. This would require a collision of the majority of the network. The blockchain is so securely designed that it becomes an example of a secure distributed computing system. Blockchains are having the high tolerance for faults. A blockchain has been able to achieve a decentralized consensus. This capability makes the blockchain an ideal tool to record a medical record, records of events, other important records, activities related to management, such as management of identity, processing of transactions, documentation of provenance, traceability of food, voting related to the process of elections etc, in future. Mr. Satoshi Nakamoto invented this technology of blockchain in the year 2008. Blockchain technology was used in the Bitcoin cryptocurrency, at first. Blockchain served as the public transaction ledger of Bitcoins. Blockchain helped to prevent the problem of double spending, in the transactions of cryptocurrency. It also removes the need of having a central server or having a controlling authority, in cryptocurrency transactions.