Blockchains: The great chain of being sure about things

The (Blockchain) technology behind bitcoin lets people who do not know or trust each other build a dependable ledger. This has implications far beyond the bitcoin cryptocurrency.
"The blockchain began life in the mind of Satoshi Nakamoto, the brilliant, pseudonymous and so far unidentified creator of bitcoin—a “purely peer-to-peer version of electronic cash”, as he put it in a paper published in 2008. To work as cash, bitcoin had to be able to change hands without being diverted into the wrong account and to be incapable of being spent twice by the same person. To fulfil Mr Nakamoto’s dream of a decentralised system the avoidance of such abuses had to be achieved without recourse to any trusted third party, such as the banks which stand behind conventional payment systems.

It is the blockchain that replaces this trusted third party. A database that contains the payment history of every bitcoin in circulation, the blockchain provides proof of who owns what at any given juncture. This distributed ledger is replicated on thousands of computers—bitcoin’s “nodes”—around the world and is publicly available. But for all its openness it is also trustworthy and secure. This is guaranteed by the mixture of mathematical subtlety and computational brute force built into its “consensus mechanism”—the process by which the nodes agree on how to update the blockchain in the light of bitcoin transfers from one person to another."

"...a world with record-keeping mathematically immune to manipulation would have many benefits. If blockchains have a fundamental paradox, it is this: by offering a way of setting the past and present in cryptographic stone, they could make the future a very different place."

Read the full article in the Economist here
Leader article: The promise of the blockchain -The trust machine