Block Chain is growing list of blocks where each block is decentralized,distributed and linked using cryptography. It was introduced in 2008 by a person or group of persons name 'Satoshi Nakamoto' in bitcoin:A peer to peer electronic cash system.Block chain contains records of digital transactions in each peers without a central authority monitoring it,but verified by other peers.These transactions are stored in form of hash which make it immutable and secure.

Features of Block Chain


        Data stored in block chain cannot be altered since every node in the network have a copy of the ledge.

Decentralized Network
           There is no centralized authority controlling the transactions on the block chain as well as every peer poses same rights.

Distributed Ledger
           Ledger on the network is maintained by all users.Data cannot be changed and all users go through the usual channels and add the new block .

           Consensus is the decision making process of a block chain.Here the nodes validate the transaction by different algorithm and add them into the block.The process is much similar to a voting process where majority choice wins.There are different types of consensus algorithm and some of them are Proof of work(POW),Proof of stake(POS) and Proof of Elapsed time(POET)


           Most cryptocurrencies use block chain technology to record transactions.For example bitcoin network and Ethereum network are both based on block chain.on 2018 may 8 facebook confirmed that it would open a new block chain group and currency Libra.