What is blockchain?
A blockchain is a continuously growing list of records, called blocks, which are linked and secured using cryptography. Each block typically contains a cryptographic hash of the previous block, a timestamp and transaction data. By this mechanism, there are thousands of identical copies of the blockchain possible in order to create a decentralized transaction network without third parties. A blockchain without decentralization is a simple and expensive transaction database. Moreover, a blockchain is just one technological component in order to create a decentralized cryptocurrency.By design, a blockchain is inherently resistant to modification of the data.
Blocks hold batches of valid transactions that are hashed and encoded into a Merkle tree. Each block includes the cryptographic hash of the prior block in the blockchain, linking the two. The linked blocks form a chain.This iterative process confirms the integrity of the previous block, all the way back to the original genesis block.
What is blockchain used for?
The primary use of blockchains today is as a distributed ledger for cryptocurrencies, most notably bitcoin.