  The past decade has witnessed the rapid evolution in blockchain technologies,
which has attracted tremendous interests from both the research communities and
industries. The blockchain network was originated from the Internet financial
sector as a decentralized, immutable ledger system for transactional data
ordering. Nowadays, it is envisioned as a powerful backbone/framework for
decentralized data processing and data-driven self-organization in flat,
open-access networks. In particular, the plausible characteristics of
decentralization, immutability and self-organization are primarily owing to the
unique decentralized consensus mechanisms introduced by blockchain networks.
This survey is motivated by the lack of a comprehensive literature review on
the development of decentralized consensus mechanisms in blockchain networks.
In this survey, we provide a systematic vision of the organization of
blockchain networks. By emphasizing the unique characteristics of incentivized
consensus in blockchain networks, our in-depth review of the state-of-the-art
consensus protocols is focused on both the perspective of distributed consensus
system design and the perspective of incentive mechanism design. From a
game-theoretic point of view, we also provide a thorough review on the strategy
adoption for self-organization by the individual nodes in the blockchain
backbone networks. Consequently, we provide a comprehensive survey on the
emerging applications of the blockchain networks in a wide range of areas. We
highlight our special interest in how the consensus mechanisms impact these
applications. Finally, we discuss several open issues in the protocol design
for blockchain consensus and the related potential research directions.
