arXiv subjects

Isaac Doidge

Publications and source records attributed to Isaac Doidge.

2 recordsLinked to original sources

arXiv2024

Formally Verifying the Safety of Pipelined Moonshot Consensus Protocol

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.

cs.LO↗

arXiv2024

Moonshot: Optimizing Chain-Based Rotating Leader BFT via Optimistic Proposals

Existing chain-based rotating-leader BFT SMR protocols for the partially synchronous network model with constant commit latencies incur block periods of at least $2\delta$ (where $\delta$ is the message transmission latency). While a protocol with a block period of $\delta$ exists under the synchronous model, its commit latency is linear in the size of the system. To close this gap, we present the first chain-based BFT SMR protocols with $\delta$ delay between the proposals of consecutive honest leaders and commit latencies of $3\delta$. We present three protocols for the partially synchronous model under different notions of optimistic responsiveness, two of which implement pipelining. All of our protocols achieve reorg resilience and two have short view lengths; properties that many existing chain-based BFT SMR protocols lack. We present an evaluation of our protocols in a wide-area network wherein they demonstrate significant increases in throughput and reductions in latency compared to the state-of-the-art, Jolteon. Our results also demonstrate that techniques commonly employed to reduce communication complexity$\unicode{x2014}$such as vote-pipelining and the use of designated vote-aggregators$\unicode{x2014}$actually reduce practical performance in many settings.

cs.DC↗