Blockchain is a shared ledger of data e.g., transactions or code that are batched into blocks, verified, and subsequently accepted as part of the blockchain by a network of distributed users (nodes) through a consensus mechanism. At its most basic, a blockchain is a list of transactions that anyone can view and verify.
Blockchain relies on the principles of consensus, decentralization, and cryptography for ensuing trust in transactions. With cryptographic security and the assurance that no one can modify data without the knowledge of other participants. The network is distributed and has thousands of nodes all over the world that keep track of all transactions happening on the system. This ensures that in case something goes wrong on one server, there are others to pick up the slack. Hacking into any one server is meaningless. Cryptocurrencies like Bitcoin and Ethereum are powered by a technology called the blockchain.
From Blockchain to cryptocurrencies
Blockchain is a platform that drives cryptocurrency and is a technology that acts as a distributed ledger for the network. The network creates a means of transaction and enables the transfer of value and information. Miners in Blockchain accept transactions, mark them as legitimate and broadcast them across the network. After the miner confirms the transaction, each node must add it to its database. In layman terms, it has become part of the Blockchain and miners undertake this work to obtain cryptocurrency tokens, such as Bitcoin.