  For a decentralized and transparent society, blockchain technology has been
developed. Along with this, quite a few consensus algorithms that are one of
core technologies in blockchain have been proposed. Among them, we analyze a
consensus algorithm called LFT2, which is used by a blockchain system, ICON. We
first formulate the LFT2 consensus algorithm and then analyze safety and
liveness, which can be considered as the most important properties in
distributed consensus system. We prove that LFT2 satisfies safety and liveness,
where a certain assumption is required to prove liveness. In addition, we
compare LFT2 with two similar consensus algorithms, and from the comparison, we
show that a trade-off exist among the three consensus algorithms. Finally, we
simulate LFT2 to measure a liveness quality.
