Blockchain technology was initially developed as part of the cryptographic currency Bitcoin. However, the two are far from limited to each other. Blockchain can support a wide range of applications. Moreover, blockchain technology is already being used in various projects such as peer-to-peer payment services, supply chain tracking, notary services and others.
A its heart, blockchain is a type of distributed ledger, consisting of blocks of data. Each block is then “chained” to the next block, using a cryptographic hash referencing the previous block. This allows blockchains to be used like a ledger, which can be shared and accessed by anyone with the appropriate permissions.
Furthermore, Blockchain is designed to store information in a way that makes it virtually impossible to add, remove or change data without being detected by other users.
Today, transactions are verified by a central authority—like a government or a credit card clearinghouse. Blockchain applications could replace these centralised systems with decentralised ones, where verification comes from the consensus of multiple users.
What is a Block?
A block is a data structure containing aggregated transaction data. Blocks are cryptographically linked together to form the larger data structure called a blockchain. The first block in any given blockchain is called the “genesis block.”
Here is an awesome video with the basic information of how blockchains work. Take a look.