Blockchain is a database that is replicated and shared via a peer to peer network of computers. Hence the concept of a distributed ledger that is a public record of transactions. Whenever a change is made on the ledger, it is broadcasted across the network of computers and changes all other copies of the database if the algorithms run by the computers determine that the transaction is valid. This distributed ledger is also highly secure as one participant cannot alter one part of the ledger without altering the large number of replicated copies held across a network of participants. Blockchain allows the transfer of assets between two parties without the need for trust and increases the auditability and efficiency of transactions as well as remove the need for third parties thus reducing costs of these transactions. Blockchain also exists in two states: Public or Private