Today's blockchain designs suffer from a trilemma claiming that no blockchain system can simultaneously achieve decentralization, security, and performance scalability. For current blockchain systems, as more nodes join the network, the efficiency of the system (computation, communication, and storage) stays constant at best. A leading idea for enabling blockchains to scale efficiency is the notion of sharding: different subsets of nodes handle different portions of the blockchain, thereby reducing the load for each individual node. However, existing sharding proposals achieve efficiency scaling by compromising on trust - corrupting the nodes in a given shard will lead to the permanent loss of the corresponding portion of data. In this paper, we settle the trilemma by demonstrating a new protocol for coded storage and computation in blockchains. In particular, we propose PolyShard: “polynomially coded sharding” scheme that achieves information-theoretic upper bounds on the efficiency of the storage, system throughput, as well as on trust, thus enabling a truly scalable system. We provide simulation results that numerically demonstrate the performance improvement over state of the arts, and the scalability of the PolyShard system. Finally, we discuss potential enhancements, and highlight practical considerations in building such a system.

中文翻译：

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PolyShard：编码分片同时实现线性扩展效率和安全性


当今的区块链设计面临着三难困境，即没有任何区块链系统可以同时实现去中心化、安全性和性能可扩展性。对于当前的区块链系统来说，随着越来越多的节点加入网络，系统的效率（计算、通信和存储）最多保持不变。使区块链能够提高效率的一个主要思想是分片的概念：不同的节点子集处理区块链的不同部分，从而减少每个节点的负载。然而，现有的分片提案通过损害信任来实现效率扩展——破坏给定分片中的节点将导致相应部分数据的永久丢失。在本文中，我们通过演示区块链中编码存储和计算的新协议来解决这个难题。特别是，我们提出了 PolyShard：“多项式编码分片”方案，该方案实现了存储效率、系统吞吐量以及信任的信息论上限，从而实现了真正可扩展的系统。我们提供的模拟结果以数字方式证明了 PolyShard 系统相对于现有技术的性能改进以及可扩展性。最后，我们讨论潜在的增强功能，并强调构建此类系统的实际考虑因素。