Blockchain

Each block typically contains a hash pointer as a link to a previous block, a timestamp and transaction data. By design, a blockchain is inherently 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 collusion 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. Decentralized consensus has therefore been claimed with a blockchain.

Blockchain was invented by a person (or group of people) using the name Satoshi Nakamoto in 2008 to serve as the public transaction ledger of the cryptocurrency bitcoin. The identity of Satoshi Nakamoto is unknown. The invention of the blockchain for bitcoin made it the first digital currency to solve the double-spending problem without the need of a trusted authority or central server. The bitcoin design has inspired other applications, and blockchains that are readable by the public are widely used by cryptocurrencies. Private blockchains have been proposed for business use.

A blockchain is a decentralized, distributed and public digital ledger that is used to record transactions across many computers so that the record cannot be altered retroactively without the alteration of all subsequent blocks and the collusion of the network. The basic principle behind blockchain is that there is no single point of control or failure. Because the ledger is distributed across a network of computers, it is virtually impossible to hack or tamper with. This makes blockchain an extremely secure way to store data. In addition to being secure, blockchain is also transparent.

Because all transactions are publicly recorded on the ledger, anyone can view the transaction history of any given address. This transparency makes it possible to hold businesses and individuals accountable for their actions. Blockchain is often lauded as a revolutionary technology that has the potential to change the way the world does business. While it is still in its early stages, blockchain has already begun to disrupt many industries.