What’s a Blockchain?¶
A blockchain is a decentralized distributed ledger that records transactions in an append-only manner. The term “Blockchain” actually describes very well what the technology is all about.
Block + Chain¶
The way it works is that transaction data are bundled into digital blocks and each new block is linked to the previous block, creating a continuous chain. Blocks that are already submitted to the ledger are immutable and cannot be changed. However, they can be updated by appending a new set of data (blocks) to the chain that overrides the previous state of the data. All transactions are cryptographically signed and identified so that all parties can verify who did what in the network.
The definition of blockchain can be simplified to a general statement, that it is an audit or history tracking system.