  Byzantine consensus is a critical component in many permissioned Blockchains
and distributed ledgers. We propose a new paradigm for designing BFT protocols
called DQBFT that addresses three major performance and scalability challenges
that plague past protocols: (i) high communication costs to reach
geo-distributed agreement, (ii) uneven resource utilization hampering
performance, and (iii) performance degradation under varying node and network
conditions and high-contention workloads. Specifically, DQBFT divides consensus
into two parts: 1) durable command replication without a global order, and 2)
consistent global ordering of commands across all replicas. DQBFT achieves this
by decentralizing the heavy task of replicating commands while centralizing the
ordering process.
  Under the new paradigm, we develop a new protocol, Destiny that uses a
combination of three techniques to achieve high performance and scalability:
using a trusted subsystem to decrease consensus's quorum size, using threshold
signatures to attain linear communication costs, reducing client communication.
Our evaluations on 300-replica geo-distributed deployment reveal that DQBFT
protocols achieve significant performance gains over prior art: $\approx$3x
better throughput and $\approx$50\% better latency.
