Barracuda: The Power of ℓ-polling in Proof-of-Stake Blockchains
Barracuda: The Power of ℓ-polling in Proof-of-Stake Blockchains
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DOI：
10.1145/3323679.3326533
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发表时间：
2019-07
期刊：
影响因子：
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通讯作者：
G. Fanti;Jiantao Jiao;Ashok Vardhan Makkuva;Sewoong Oh;Ranvir Rana;P. Viswanath
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文献类型：
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作者：
G. Fanti;Jiantao Jiao;Ashok Vardhan Makkuva;Sewoong Oh;Ranvir Rana;P. Viswanath
区块链是由分布式节点组维护的顺序事件数据库。区块链中的一个关键共识问题是确定序列中的下一个块（数据元素）。许多区块链通过选择一个新节点来提出每个新区块来解决这个问题。新区块（通常）被附加到提议者的本地区块链的尖端，随后广播到网络的其余部分。如果没有网络延迟（或对抗行为），这个过程将给出一个完美的链，因为每个提议者都有相同的区块链视图。实践中的一个主要挑战是分叉。由于网络延迟，提议者可能还没有获得最近的区块，因此可能会创建一个从主链中间分叉的侧链。分叉降低了吞吐量，因为只有一个主链可以存活，所有其他块都被丢弃。我们为区块链提出了一种新的P2P协议，称为Barracuda，其中每个提议者在提出一个区块之前，轮询其他节点以获取其本地区块树信息。在一个随机网络模型下，我们证明了这种轻量级原语提高了吞吐量，就好像整个网络是一个因子。我们提供了如何在实践中实现Barracuda的指导方针，保证对几个现实世界因素的稳健性。
A blockchain is a database of sequential events that is maintained by a distributed group of nodes. A key consensus problem in blockchains is that of determining the next block (data element) in the sequence. Many blockchains address this by electing a new node to propose each new block. The new block is (typically) appended to the tip of the proposer's local blockchain, and subsequently broadcast to the rest of the network. Without network delay (or adversarial behavior), this procedure would give a perfect chain, since each proposer would have the same view of the blockchain. A major challenge in practice is forking. Due to network delays, a proposer may not yet have the most recent block, and may therefore create a side chain that branches from the middle of the main chain. Forking reduces throughput, since only one a single main chain can survive, and all other blocks are discarded. We propose a new P2P protocol for blockchains called Barracuda, in which each proposer, prior to proposing a block, polls ℓ other nodes for their local blocktree information. Under a stochastic network model, we prove that this lightweight primitive improves throughput as if the entire network were a factor of ℓ faster. We provide guidelines on how to implement Barracuda in practice, guaranteeing robustness against several real-world factors.