Blockchain is a digital ledger that provides a most secure way of processing transactions. Blockchain acts as a decentralized database that stores collections of transactions over peer to peer network. In peer to peer network  everyone can securely access data. Each transaction in the public ledger is validated by participating nodes in network.  All the valid transactions are stored in the form of Blocks.Each block is connected or chained to previous block through hashing.In short we can say it forms a chain of blocks so we called it Blockchain.

Bitcoin is most popular example based on Blockchain. (Bitcoin is a form of digital currency)

Types of Blockchain:

• Public
• Private

Public blockchain :

In Public blockchain we have a public network of nodes.All the nodes can participate for creating or mining of the blocks.

Private blockchain :

In private blockchain an organization can verify transactions and perform mining.

*We will discuss more about public & private blockchain in upcoming tutorials.

Important Points:

• Blockchain is decentralized system for exchange of value
• All the valid transactions are stored in the form of blocks
• Blocks are chained through hashing.
• There is no central authority.
• Blockchain uses consensus mechanism  for validating transactions.
• Information is secured due to highly cryptographic techniques
• No one can alter information stored in blocks.

* Ledger – Collection of accounts or records

* Peer to Peer network is a distributed architecture where ‘N’ number of nodes are connected and share data without a server.