Chainlink is a popular cryptocurrency which is geared towards solving a major blockchain-based problem, that being communication to/from the blockchain. This is typically conducted through a series of sensors. Otherwise known as oracles, sensors can monitor virtually anything on the blockchain. They also expand usability, by providing an effective way to initiate smart contracts once parameters have been met. Owing to the centralised nature of oracles, they remain a weak link in the blockchain. If corruption, malfunction, or threats emerge, the whole blockchain network comes under fire. Chainlink is the first blockchain oracle network in the world.