WHAT IS BLOCKCHAIN?
Blockchain is an algorithm and distributed data structure for managing electronic cash without a central administrator among people who know nothing about one another. Originally designed for the crypto-currency Bitcoin, the blockchain architecture was driven by a radical rejection of at (government-guaranteed) money and bank-controlled payments.
Blockchain is a special instance of Distributed Ledger Technologies (DLTs), almost all of which have emerged in Bitcoin's wake.
Blockchain is a shared distributed ledger technology in which each transaction is digitally signed to ensure its authenticity and integrity — and it's poised to make big waves in a wide range of business use cases.
A blockchain is the structure of data that represents a financial ledger entry, or a record of a transaction. Each transaction is digitally signed to ensure its authenticity and that no one tampers with it, so the ledger itself and the existing transactions within it are assumed to be of high integrity.
The real magic comes, however, from these digital ledger entries being distributed among a deployment or infrastructure. These additional nodes and layers in the infrastructure serve the purpose of providing a consensus about the state of a transaction at any given second; they all have copies of the existing authenticated ledger distributed amongst them.
Blockchain is the technology the underpins digital currency (Bitcoin, Litecoin, Ethereum, and the like). The tech allows digital information to be distributed, but not copied. That means each individual piece of data can only have one owner.
source :
https://medium.com/the-mission/a-simple-explanation-on-how-blockchain-works-e52f75da6e9a