Traditional public distributed ledgers have not been able to scale-out well and work efficiently. Sharding is deemed as a promising way to solve this problem. By partitioning all nodes into small committees and letting them work in parallel, we can significantly lower the amount of communication and computation, reduce the overhead on each node's storage, as well as enhance the throughput of the distributed ledger. Existing sharding-based protocols still suffer from several serious drawbacks. The first thing is that all non-faulty nodes must connect well with each other, which demands a huge number of communication channels in the network. Moreover, previous protocols have faced great loss in efficiency in the case where the honesty of each committee's leader is in question. At the same time, no explicit incentive is provided for nodes to actively participate in the protocol. We present CycLedger, a scalable and secure parallel protocol for distributed ledger via sharding. Our protocol selects a leader and a partial set for each committee, who are in charge of maintaining intra-shard consensus and communicating with other committees, to reduce the amortized complexity of communication, computation, and storage on all nodes. We introduce a novel semi-commitment scheme between committees and a recovery procedure to prevent the system from crashing even when leaders of committees are malicious. To add incentive for the network, we use the concept of reputation, which measures each node's trusty computing power. As nodes with a higher reputation receive more rewards, there is an encouragement for nodes with strong computing ability to work honestly to gain reputation. In this way, we strike out a new path to establish scalability, security, and incentive for the sharding-based distributed ledger.

中文翻译：

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CycleLedger：通过分片实现分布式账本的可扩展且安全的并行协议

传统的公共分布式账本一直无法很好地扩展和高效工作。分片被认为是解决这个问题的一种很有前途的方法。通过将所有节点划分为小委员会并让它们并行工作，我们可以显着降低通信和计算量，减少每个节点的存储开销，并提高分布式账本的吞吐量。现有的基于分片的协议仍然存在几个严重的缺点。首先是所有非故障节点必须相互连接良好，这需要网络中大量的通信通道。此外，在每个委员会领导人的诚实度受到质疑的情况下，以前的协议在效率上面临着巨大的损失。同时，没有为节点积极参与协议提供明确的激励。我们提出了 CycLedger，这是一种通过分片实现分布式账本的可扩展且安全的并行协议。我们的协议为每个委员会选择了一个领导者和一个部分集，他们负责维护分片内的共识并与其他委员会进行沟通，以减少所有节点上的通信、计算和存储的摊销复杂度。我们在委员会之间引入了一种新颖的半承诺方案和恢复程序，以防止系统崩溃，即使委员会领导人是恶意的。为了给网络增加激励，我们使用了声誉的概念，它衡量每个节点的可信计算能力。随着声誉较高的节点获得更多的奖励，鼓励具有强大计算能力的节点诚实工作以获得声誉。通过这种方式，我们开辟了一条新途径，为基于分片的分布式账本建立可扩展性、安全性和激励机制。