The Blockchain technology that supports Bitcoin's transactions can be viewed as a network of individual databases, all linked by a Ledger system that checks and performs the exchange of values.
The network of decentralized databases allows individuals to conduct transactions among themselves, regardless of their current location.
Watch the 3 minute video that explains the Blockchain understandable.
A Blockchain (also known as block chain) is a continuously expandable list of datasets called "Blocks" that are concatenated using cryptographic techniques. Each block typically contains a cryptographically secure hash (scatter value) of the previous block, a time stamp and transaction data.
The term "Blockchain" is also used when an accounting system is decentralized and the correct state must be documented because many participants are involved in accounting. This concept is referred to as distributed ledger technology (decentralized account balance technology) or DLT. That should be documented, is irrelevant for the concept of Blockchain. Crucially, later transactions will be built on previous transactions and confirmed as correct by demonstrating knowledge of past transactions. This makes it impossible to manipulate or erase the existence or content of the previous transactions without destruction of all later transactions. Other participants in the decentralized accounting who still have knowledge of the later transactions would recognize a manipulated copy of the blockchain as having inconsistencies in the calculations.
The cryptographic chaining mechanism in a decentralized accounting system is the technical basis for Cryptocurrencies, but can also be helpful to improve or simplify transaction security in distributed systems compared to centralized systems. One of the first applications of Blockchain is the crypto-currency Bitcoin.
The functionality is similar to the Journal of accounting. It is therefore also referred to as the "Internet of values". A blockchain allows an unity between the nodes to be achieved in a decentralized network. (See also: Byzantine error.)