blockchain originally block chain is a distributed database that maintains a continuously-growing list of records called blocks.[Each block contains a timestamp and a link to a previous block. The data in a block cannot be altered retrospectively.

The first blockchain was conceptualised by Satoshi Nakamoto in 2008 and implemented the following year as a core component of the digital currency bitcoin, where it serves as the public ledger for all transactions. Through the use of a peer-to-peer network a blockchain database is managed autonomously. Blockchains are a successful example of a distributed computing system with high byzantine fault tolerance. The invention of the blockchain for bitcoin made it the first digital currency to solve the double spending problem. The bitcoin design has been the inspiration for other applications.

By design blockchains are inherently resistant to modification of the data. Decentralisedconsensus can therefore be achieved for the first time with a blockchain. This offers the potential of mass disintermediation and vast repercussions for how global trade is conducted. Financial technology, in particular blockchains have the potential to restructure the cost of transacting in a financial system. Side chains and blockchain based smart contracts are not currently used but an effort to develop those concepts is taking place.