  Blockchains is a special type of distributed systems that operates in unsafe
networks. In most blockchains, all nodes should reach consensus on all state
transitions with Byzantine fault tolerant algorithms, which creates bottlenecks
in performance. In this paper, we propose a new type of blockchains, namely
Value-Centric Blockchains (VCBs), in which the states are specified as values
(or more comprehensively, coins) with owners and the state transition records
are then specified as proofs of the ownerships of individual values. We then
formalize the "rational" assumptions that have been used in most blockchains.
We further propose a VCB, VAPOR, that guarantees secure value transfers if all
nodes are rational and keep the proofs of the values they owned, which is
merely parts of the whole state transition record. As a result, we show that
VAPOR enjoys significant benefits in throughput, decentralization, and
flexibility without compromising security.
