Origin in 1854, "a general accord or agreement of different parts in effecting a given purpose," originally a term in physiology; 1861, of persons "a general agreement in opinion;" from Latin consensus "agreement, accord," past participle of consentire "feel together," from assimilated form of com "with, together" (see con-) + sentire "to feel" (see sense (n.)). Consensus, and more importantly decentralized consensus it the goal of automating trust in the blockchain. To achieve decentralized consensus means that one party must no longer go through a central authority to share information (including information in the form of value transactions). Here come the distributed consensus mechanisms. Practical Byzantine Fault Tolerance (PBFT), Proof of Work (PoW) and Proof of Stake (PoS) are the most common consensus mechanisms. The basis of PBFT is to reach consensus on the total decisions submitted by all nodes. Hyperledger is an example of PBFT. Bitcoin is an example of PoW. Three examples of blockchain providers using the PoS consensus method are Bitshares, Nxt and Blackcoin. Ethereum is currently planning to switch from PoW to PoS with its new update “Casper”. A rather technical discussion of consensus in blockchain. Automating trust is a technical endeavor.

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Consensus building, nodes and decisions collide, blockchain transactions