In the simplest of terms, a blockchain is a time-stamped series of immutable records of data that is managed by a cluster of computers not owned by any single entity. Each of these blocks of data (i.e. block) is secured and bound to each other using cryptographic principles (i.e. chain).
In application, a blockchain, originally called block chain, is a growing list of records, called blocks, that are linked using cryptography. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data. By design, a blockchain is resistant to modification of the data. It is “an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way”.
For use as a distributed ledger, a blockchain is typically managed by a peer-to-peer network collectively adhering to a protocol for inter-node communication and validating new blocks. Once recorded, the data in any given block cannot be altered retroactively without the alteration of all subsequent blocks, which requires consensus of the network majority. Although blockchain records are not unalterable, blockchains may be considered secure by design and exemplify a distributed computing system with high Byzantine fault tolerance (Byzantine fault tolerance is the dependability of a fault-tolerant computer system, particularly distributed computing systems, where components may fail and there is imperfect information on whether a component is failed).
What is special about blockchain and why it has the capability to become one of the most disruptive technologies ever seen is that the blockchain network has no central authority. It is the very definition of a democratized system. Since it is a shared and immutable ledger, the information in it is open for anyone and everyone to see. Hence, anything that is built on the blockchain is by its very nature transparent and everyone involved is accountable for their actions.
Watch the video The Digital Currency Era to see how powerful blockchain technology really is and versatile and positively disruptive it will become in the very near future. See how the blockchain is a massive gamechanger across the planet – for all including the poorest of our global citizens.
NOTE: At the time of writing, Pres. Donald Trump is working with the USPS to roll out voting via blockchain in an effort to introduce an electoral system less open to corruption and fraud.