Conference：The 54th Annual IEEE/IFIP International Conference on Dependable Systems and Networks
Conference time：2024
5、A Low-Latency Random Number Generator for BFT Smart Contracts
为 BFT 智能合约设计的低延迟随机数生成器
Random numbers are essential in decentralized applications such as decentralized finance (DeFi) and non-fungible tokens (NFTs). However, their generation is challenging due to the deterministic and decentralized nature of blockchains, which can compromise the security and stability of smart contracts. Previous solutions, including Oracles that use commit-execute schemes, suffer from high transaction fees, long processing times, and increased on-chain storage, affecting efficiency. This paper introduces a new random number provider (RNP) protocol for smart contracts that eliminates reliance on traditional commit-execute methods. We also systematically identify potential attacks related to random numbers in smart contracts, particularly Post-Reveal Undo Attacks (PUAs), where attackers may reverse contract operations when randomness is unfavorable, and discuss the necessary security requirements. Our protocol mitigates these attacks by (1) integrating distributed random beacons (DRBs) with consensus processes, bridging the semantic gap between DRB and consensus, and (2) thoroughly analyzing and classifying four types of PUAs, offering robust mitigations, and providing a security proof. Our experiments demonstrate that the protocol significantly improves response times and security for random number queries in smart contracts, reducing request fees by at least 89% and on-chain data by 76.4% compared to current methods. This work advances the integration of DRB protocols and consensus mechanisms, securing and optimizing random number applications in dApps, thus fostering the creation of more reliable and robust systems.
Pdf link:https://dsn2024uq.github.io/Proceedings/pdfs/DSN2024-6rvE3SSpzFYmysif75Dkid/410500a389/410500a389.pdf
6、Verifying Randomized Consensus Protocols with Common Coins
使用Common Coins验证随机共识协议
Randomized consensus, Threshold automata, Distributed protocols, Common coin
随机共识、阈值自动机、分布式协议、Common Coin
Randomized fault-tolerant consensus protocols with common coins are widely used in cloud computing and blockchain platforms. Due to their fundamental role, it is crucial to ensure their correctness. Threshold automata is a formal model specifically designed for the verification of fault-tolerant consensus protocols. Recently, it has been extended to probabilistic threshold automata (PTAs) to verify randomized fault-tolerant consensus protocols. However, PTAs are currently limited to modeling randomized consensus protocols with local coins. In this paper, we extend PTAs to accommodate the verification of randomized fault-tolerant consensus protocols that incorporate common coins. Our approach introduces a novel process that simulates the common coin, referred to as the “common-coin process.” While the integration of the common-coin process disrupts the inherent symmetry and presents technical challenges, we demonstrate how PTAs can be effectively adapted to address these issues. We apply this methodology to validate the agreement, validity, and almost-certain termination properties of eight randomized consensus protocols featuring common coins.
Pdf link:https://dsn2024uq.github.io/Proceedings/pdfs/DSN2024-6rvE3SSpzFYmysif75Dkid/410500a403/410500a403.pdf
7、Efficient Asynchronous Approximate Agreement for Distributed Oracles
分布式预言机的高效异步近似协议
Agreement protocols are crucial in various emerging applications, spanning from distributed (blockchains) oracles to fault-tolerant cyber-physical systems. In scenarios where sensor/oracle nodes measure a common source, maintaining output within the convex range of correct inputs, known as convex validity, is imperative. Present asynchronous convex agreement protocols employ either randomization, incurring substantial computation overhead, or approximate agreement techniques, leading to high O(n^3) communication for an n-node system. This paper introduces Delphi, a deterministic protocol with O(n^2) communication and minimal computation overhead. Delphi assumes that honest inputs are bounded, except with negligible probability, and integrates agreement primitives from literature with a novel weighted averaging technique. Experimental results highlight Delphi’s superior performance, showcasing a significantly lower latency compared to state-of-the-art protocols. Specifically, for an n=160-node system, Delphi achieves an 8x and 3x improvement in latency within CPS and AWS environments, respectively.
Pdf link:https://dsn2024uq.github.io/Proceedings/pdfs/DSN2024-6rvE3SSpzFYmysif75Dkid/410500a456/410500a456.pdf
8、Enhancing Block Interval and Commit Efficiency in Chain-Driven Rotating Leader BFT
在链驱动的轮换领导者 BFT 中增强区块间隔和提交效率
In the realm of partially synchronous networks, traditional chain-based rotating-leader Byzantine Fault Tolerance (BFT) State Machine Replication (SMR) protocols necessitate a block period of no less than 2δ, where δ represents the message propagation delay. Although a protocol with a block period of δ is feasible under a fully synchronous model, the associated commit latency scales linearly with the system’s size. Bridging this gap, we introduce the inaugural chain-based BFT SMR protocols that achieve a δ time delay between consecutive honest leader proposals and a commit latency of 3δ. We unveil three protocols tailored for the partially synchronous model, each embodying varying degrees of optimistic responsiveness, with two of them incorporating a pipeline mechanism. Our protocols not only exhibit reorganization resilience but also feature shorter view lengths, attributes that are notably absent in many current chain-based BFT SMR protocols. Our comprehensive evaluation within a wide-area network setting reveals a substantial surge in throughput and a marked decrease in latency, outperforming the industry-leading Jolteon. Additionally, our findings indicate that conventional methods aimed at diminishing communication complexity, such as vote-pipelining and the employment of designated vote-aggregators, may actually detract from practical performance in numerous scenarios.
