  Transaction throughput, confirmation latency and confirmation reliability are
fundamental performance measures of any blockchain system in addition to its
security. In a decentralized setting, these measures are limited by two
underlying physical network attributes: communication capacity and
speed-of-light propagation delay. Existing systems operate far away from these
physical limits. In this work we introduce Prism, a new proof-of-work
blockchain protocol, which can achieve 1) security against up to 50%
adversarial hashing power; 2) optimal throughput up to the capacity C of the
network; 3) confirmation latency for honest transactions proportional to the
propagation delay D, with confirmation error probability exponentially small in
CD ; 4) eventual total ordering of all transactions. Our approach to the design
of this protocol is based on deconstructing the blockchain into its basic
functionalities and systematically scaling up these functionalities to approach
their physical limits.
