Thomas Locher, Yvonne-Anne Pignolet, ABB Corporate Research, Baden-Dättwil, Switzerland
At a glance:
A blockchain is a distributed database that is used to maintain a continuously growing list of records. A distributed database is a database that is replicated across multiple machines to achieve fault tolerance. Lists of records are compiled into so called blocks, which further contain a time stampand a link to the previous block, thus forming achain of blocks. The machines ensure consistency among the replicas in a peer-to-peer fashion by executing a protocol to verify validity conditions and ensure agreement on the next block to be added to the blockchain. Since consensus on the blocks is required, it is infeasible for a single machine to deviate, thereby guaranteeing immutability of records.
The blockchain concept was invented to enable the exchange of the virtual currency Bitcoin without having to rely on trust or centralized control by anyone institution. Subsequently, other use cases and blockchains with different properties have been proposed. In general, a blockchain can serve as a distributed ledger that can store arbitrary records involving one or multiple parties efficiently and in a verifiable and permanent way. For example, the finance industry envisions simplified international inter-bank communication and transactions using blockchain technology. In an industrial context, provenance, ownership and tracking of virtual andphysical goods might benefit from the immutability, fault-tolerance and scalability properties of blockchain-based approaches.