Universally Composable Synchronous Computation
Universally Composable Synchronous Computation
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DOI：
10.1007/978-3-642-36594-2_27
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发表时间：
2013-03
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通讯作者：
Jonathan Katz;U. Maurer;Björn Tackmann;Vassilis Zikas
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文献类型：
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作者：
Jonathan Katz;U. Maurer;Björn Tackmann;Vassilis Zikas
在同步网络中，协议可以实现在异步世界中不可能实现的安全保证：它们可以同时实现输入完整性（所有诚实方的输入都包含在计算中）和保证终止（诚实方不会无限期地“挂起”）。在实践中，真正的同步网络很少存在，但是如果信道具有（已知的）有限延迟，并且各方具有松散同步的时钟，则可以模拟同步。广泛使用的通用可组合性（UC）框架本质上是异步的，但是已经提出了几种向框架添加同步的方法。然而，我们表明，现有的建议不提供预期的保证。鉴于此，我们提出了一种新的方法来定义UC框架中的同步，通过引入分别用于建模的有界延迟网络和松散同步时钟的功能。我们表明，在给定这些功能的情况下，可以实现同步计算的预期保证，并且以前的类似模型都可以在我们的新框架中表示。
In synchronous networks, protocols can achieve security guarantees that are not possible in an asynchronous world: they can simultaneously achieveinput completeness(all honest parties’ inputs are included in the computation) andguaranteed termination(honest parties do not “hang” indefinitely). In practice truly synchronous networks rarely exist, but synchrony can be emulated if channels have (known) bounded latency and parties have loosely synchronized clocks.The widely-used framework of universal composability (UC) is inherently asynchronous, but several approaches for adding synchrony to the framework have been proposed. However, we show that the existing proposals donotprovide the expected guarantees. Given this, we propose a novel approach to defining synchrony in the UC framework by introducing functionalities exactly meant to model, respectively, bounded-delay networks and loosely synchronized clocks. We show that the expected guarantees of synchronous computation can be achieved given these functionalities, and that previous similar models can all be expressed within our new framework.