While widely known as the underlying technology for Bitcoin, blockchain may be best understood as a means of storing data. Generally speaking, a blockchain — and yes, there are many — is a sequence of records, shared among a network, that are both accessible and immutable, meaning no member can change or delete the data within them without invalidating the rest of the sequence. The exact definition is still a matter of debate among experts, but most agree that the aim, at least, is to produce a ledger that’s difficult to tamper with and easy to verify independently. A retailer, for instance, might want to record its end-to-end supply chain data on a blockchain in order to track inventory or combat counterfeits (more on both of these ideas later). For this to work, each entity — from factory to distributor to shipper to warehouse to store — would need to participate so that there are no gaps in the data. Then every time a new transaction is logged (say, when a container is scanned at a port or an item is placed on a shelf), it could be validated and bundled with other transactions into a “block,” which would be linked to other blocks to form a blockchain. Copies of the data would be stored across multiple devices called “nodes,” creating a decentralized system that acts as a safeguard against hacking. Read more at Vox.