The present invention is directed blockchain systems and censuses protocols that adopt a pipelining technique. The systems and protocols involve a committee of consensus nodes that include proposer nodes and voter nodes. Each proposer node can send two or more unnotarized proposals to the voter nodes, and the voter nodes can vote on an unnotarized proposal when they have the same freshest notarized chain or block. A sequence number is provided to facilitate the operation of the systems and protocols. The sequence number can be used to determine the freshest notarized chain or block and the finalized chain and switch proposer node. The systems and protocols also provide other features such as chain syncer, committee election scheme, and committee reconfiguration. The systems and protocols further provide a simple finalization process and thus have a low finalization time.