Blockchain
A block-chain is an electronic, secure, public, distributed, and linked list of records, called blocks, used to create a verifiable, and permanent ledger of transactions:
- Each transaction is between two parties
- Each transaction records the public identifier or key of both parties with a timestamp in a block
- A block contains many transactions
- Each block is linked using a cryptographic hash to the previous and next record thereby forming a chain.
- A set of blocks chained together forms a ledger
- Each copy of the ledger is complete i.e. it contains all the blocks in a chain so it contains all transactions recorded.
- Copies of this ledger are distributed amongst owners
- To alter a recorded transaction, all "owners" of the copies of a ledger must consent
The blockchain is an incorruptible digital ledger of economic transactions that can be programmed to record not just financial transactions but virtually everything of value. [1]
Source: Blockgeeks
Blockchain was invented by Satoshi Nakamoto in 2008 for use in the cryptocurrency bitcoin, as its public transaction ledger.[2]