The blockchain is a transaction database shared by all nodes involved in the system based on the Bitcoin protocol. It is a data structure consisting of linked blocks (e.g. confirmed financial transactions) that refer to or refer to earlier ones and form a chain in linear chronological order. A full copy of any transaction that has ever been made in any currency is contained within the full copies of the block chain of any currency

Bitcoin and an extension of the blockchain was created by someone nicknamed Satoshi Nakamoto