  Decentralized Finance (DeFi) has emerged as a contemporary competitive as
well as complementary to traditional centralized finance systems. As of 23rd
January 2024, per Defillama approximately USD 55 billion is the total value
locked on the DeFi applications on all blockchains put together.
  A Byzantine Fault Tolerant (BFT) State Machine Replication (SMR) protocol,
popularly known as the consensus protocol, is the central component of a
blockchain. If forks are possible in a consensus protocol, they can be misused
to carry out double spending attacks and can be catastrophic given high volumes
of finance that are transacted on blockchains. Formal verification of the
safety of consensus protocols is the golden standard for guaranteeing that
forks are not possible. However, it is considered complex and challenging to
do. This is reflected by the fact that not many complex consensus protocols are
formally verified except for Tendermint and QBFT.
  We focus on Supra's Pipelined Moonshot consensus protocol. Similar to
Tendermint's formal verification, we too model Pipelined Moonshot using IVy and
formally prove that for all network sizes, as long as the number of Byzantine
validators is less than one thirds, the protocol does not allow forks, thus
proving that Pipelined Moonshot is safe and double spending cannot be done
using forks. The IVy model and proof of safety is available on Github.
