ConChain: A Scheme for Contention-free and Attack Resilient BlockChain
Faisal Haque Bappy, Tariqul Islam, Tarannum Shaila Zaman, Md Sajidul Islam Sajid, Mir Mehedi Ahsan Pritom
TL;DR
Contention among conflicting transactions in blockchains leads to higher latency and wasted resources, especially under heavy workloads. ConChain tackles this by introducing a two-layer enhancement to the ordering process: a Dependency Manager that analyzes dependencies and a Transaction Assigner that schedules conflict-free work and coordinates parallel processing. The paper formalizes contention definitions, compares naive reduction strategies, and presents an architecture that achieves contention-free execution and resilience against four major attacks. If deployed, ConChain could substantially improve throughput and robustness for blockchain systems in both private and public deployments.
Abstract
Although blockchains have become widely popular for their use in cryptocurrencies, they are now becoming pervasive as more traditional applications adopt blockchain to ensure data security. Despite being a secured network, blockchains have some tradeoffs such as high latency, low throughput, and transaction failures. One of the core problems behind these is improper management of "conflicting transactions", which is also known as "contention". When there is a large pool of pending transactions in a blockchain and some of them are conflicting, a situation of contention occurs, and as a result, the latency of the network increases, and a substantial amount of resources are wasted which results in low throughput and transaction failures. In this paper, we proposed ConChain, a novel blockchain scheme that combines transaction parallelism and an intelligent dependency manager to minimize conflicting transactions in blockchain networks as well as improve performance. ConChain is also capable of ensuring proper defense against major attacks due to contention.