A blockchain is a shared digital register of recorded data. For cryptocurrencies, this is the transaction history for every unit of the cryptocurrency, which shows how ownership has changed over time. Blockchain works by recording transactions in ‘blocks’, with new blocks added at the front of the chain.
Blockchain technology has unique security features that normal computer files do not have.
A blockchain file is always stored on multiple computers across a network – rather than in a single location – and is usually readable by everyone within the network. This makes it both transparent and very difficult to alter, with no one weak point vulnerable to hacks, or human or software error.
Blocks are linked together by cryptography – complex mathematics and computer science. Any attempt to alter data disrupts the cryptographic links between blocks, and can quickly be identified as fraudulent by computers in the network.