Blockchain is a shared, peer-to-peer database, a type of distributed ledger. While there are currently several different kinds of blockchains in existence, they share certain functional characteristics. They generally have a means for nodes on the network to communicate directly with each other. They have some sort of mechanism for nodes on the network to propose the addition of information to the database, usually in the form of some transaction, and some sort of consensus mechanism by which the other nodes on the network can validate this information and then store it. Blockchain gets its name from the fact that data is stored in groups known as blocks, and that each validated block gets cryptographically sealed on to the previous block, forming an ever-growing chain of data. Instead of being stored in a central location, all the nodes in the network share an identical copy of the blockchain, continuously updating it as new valid blocks are added.