On Bitcoin cash's target recalculation functions
On Bitcoin cash's target recalculation functions
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关于比特币现金的目标重算函数
DOI：
10.1145/3479722.3480998
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Shen, Yu
中科院分区：
文献类型：
--
作者：
Garay, Juan;Shen, Yu
比特币现金创建于2017年，是比特币的“硬分叉”，以满足允许更高交易量的需求。这是通过一个更大的块大小，以及一个新的难度调整（目标重新计算）作用更频繁的函数（与比特币每两周进行一次的难度调整相反），导致每个区块的目标可能不同。虽然在实践中似乎实现了目标，据我们所知，没有正式的分析来支持这一建议。在本文中，我们提供了第一个正式的加密分析比特币现金的目标重新计算功能-ASERT和SMA（分别为当前和以前的重新计算功能）-对抗所有可能的对手。与比特币的主要区别在于，它们不再是基于时代的，因此之前的分析无法成立。我们通过引入一组新的分析工具来克服这一技术障碍，这些工具专注于滑动窗口中块的时间戳的“校准”，从而产生接近初始块生成率的度量。有了这个措施，我们然后遵循比特币主干协议[Eurocrypt 2015及其后续协议]中开发的分析方法，首先建立区块链数据结构的基本属性，从这些属性中可以获得强大的交易分类账的属性。我们将我们的分析结果与比特币现金网络的数据进行了比较，并得出结论，为了满足安全性，（即，除了在安全参数中具有可忽略的概率之外满足的特性）相对于在实践中使用的参数值，应当使用相当大的参数值。
Bitcoin Cash, created in 2017, is a "hard fork" from Bitcoin responding to the need for allowing a higher transaction volume. This is achieved by a larger block size, as well as a new difficulty adjustment (target recalculation) function that acts more frequently (as opposed to Bitcoin's difficulty adjustment happening about every two weeks), resulting in a potentially different targetfor each block.While seemingly achieving its goal in practice, to our knowledge there is no formal analysis to back this proposal up.In this paper we provide the first formal cryptographic analysis of Bitcoin Cash's target recalculation functions---both ASERT and SMA (current and former recalculation functions, respectively)---against all possible adversaries. The main distinction with respect to Bitcoin's is that they are no longer epoch-based, and as such previous analyses fail to hold. We overcome this technical obstacle by introducing a new set of analytical tools focusing on the "calibration" of blocks' timestamps in sliding windows, which yield a measure of closeness to the initial block generation rate. With that measure, we then follow the analytical approach developed in theBitcoin backbone protocol[Eurocrypt 2015 and follow-ups] to first establish the basic properties of the blockchain data structure, from which the properties of a robust transaction ledger (namely,ConsistencyandLiveness) can be derived.We compare our analytical results with data from the Bitcoin Cash network, and conclude that in order to satisfy security (namely, properties satisfied except with negligible probability in the security parameter) considerably larger parameter values should be used with respect to the ones used in practice.
吞吐量不稳定：当难度算法失效时
DOI：
--
发表时间：
2020
期刊：
International Conference on Blockchain
影响因子：
--
作者：
Sam M. Werner;D. Ilie;I. Stewart;W. Knottenbelt
通讯作者：
W. Knottenbelt