  SURFACE, standing for Secure, Use-case adaptive, and Relatively Fork-free
Approach of Chain Extension, is a consensus algorithm that is designed for
real-world networks and enjoys the benefits from both the Nakamoto consensus
and Byzantine Fault Tolerance (BFT) consensus. In SURFACE, a committee is
randomly selected every round to validate and endorse the proposed new block.
The size of the committee can be adjusted according to the underlying network
to make the blockchain mostly fork-free with a reasonable overhead in
communication. Consequently, the blockchain can normally achieve fast
probabilistic confirmation with high throughput and low latency. SURFACE also
provides a BFT mechanism to guarantee ledger consistency in case of an extreme
network situation such as large network partition or being under massive DDoS
attacks.
