论文标题
在异步汇款系统中的付款渠道上
On Payment Channels in Asynchronous Money Transfer Systems
论文作者
论文摘要
汇款是一种抽象，意识到加密货币的核心。已经表明，与共同的信念相反，在存在拜占庭断层的情况下，可以在异步网络中实施货币转移，而不需要共识。尽管如此，现有的汇款实施仍然需要每笔付款的二次消息复杂性，从而试图努力扩展。在常见的区块链中，例如比特币和以太坊，这一成本是通过在区块链顶部的第二层实施的付款渠道来降低的，从而可以在两个共享一个频道的用户之间进行许多链付款。此类渠道仅需要链接交易才能开放和关闭，而中间付款则是链接的，并具有持续的消息复杂性。但是今天使用付款渠道需要同步，因此它们不足以进行异步汇款系统。 在本文中，我们为异步汇款系统中的付款渠道提供了一系列可能性和不可能的结果。我们首先证明对链接转移的消息复杂性的二次下限。然后，我们探索两种类型的付款渠道，即单向和双向。我们将它们定义为共享内存摘要，并证明在某些情况下，它们可以作为第二层在异步转移系统之上的第二层实现，而在其他情况下则是不可能的。
Money transfer is an abstraction that realizes the core of cryptocurrencies. It has been shown that, contrary to common belief, money transfer in the presence of Byzantine faults can be implemented in asynchronous networks and does not require consensus. Nonetheless, existing implementations of money transfer still require a quadratic message complexity per payment, making attempts to scale hard. In common blockchains, such as Bitcoin and Ethereum, this cost is mitigated by payment channels implemented as a second layer on top of the blockchain allowing to make many off-chain payments between two users who share a channel. Such channels only require on-chain transactions for channel opening and closing, while the intermediate payments are done off-chain with constant message complexity. But payment channels in-use today require synchrony, therefore they are inadequate for asynchronous money transfer systems. In this paper, we provide a series of possibility and impossibility results for payment channels in asynchronous money transfer systems. We first prove a quadratic lower bound on the message complexity of on-chain transfers. Then, we explore two types of payment channels, unidirectional and bidirectional. We define them as shared memory abstractions and prove that in certain cases they can be implemented as a second layer on top of an asynchronous money transfer system whereas in other cases it is impossible.
