Consistency, availability, and partition tolerance in blockchain: a survey on the consensus mechanism over peer-to-peer networking

Blockchain is a disruptive technology that relies on the distributed nature of the peer-to-peer network while performing an agreement, or consensus, a mechanism to achieve an immutable, global, and consistent registry of all transactions. Thus, a key challenge in developing blockchain solutions is to design the consensus mechanism properly. As a consequence of being a distributed application, any consensus mechanism is restricted to offer two of three properties: consistency, availability, and partition tolerance. In this paper, we survey the main consensus mechanisms on blockchain solutions, and we highlight the properties of each one. Moreover, we differentiate both deterministic and probabilistic consensus mechanisms, and we highlight coordination solutions that facilitate the data distribution on the blockchain, without the need for a sophisticated consensus mechanism.