Short Paper: Revisiting Difficulty Control for Blockchain Systems
Short Paper: Revisiting Difficulty Control for Blockchain Systems
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DOI：
10.1007/978-3-319-67816-0_25
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发表时间：
2017-09
期刊：
影响因子：
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通讯作者：
D. Meshkov;A. Chepurnoy;M. Jansen
中科院分区：
文献类型：
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作者：
D. Meshkov;A. Chepurnoy;M. Jansen
比特币白皮书[1]指出，只要诚实的矿工控制了当前总计算能力的一半以上，系统的安全性就得到了保证。白皮书假设了一个静态的困难，因此对于系统历史的任何给定时刻，解决加密工作量证明难题同样困难。然而，真实的比特币网络使用的是自适应的难度调整机制。本文介绍并分析了一种针对比特币中使用的挖掘难度重定向功能的新型攻击，我们称之为“跳币”。在跳币攻击中，恶意矿工在增加其挖矿利润的同时，也增加了块间的平均延迟。为了降低跳币攻击的动机，同时减少块间延迟，我们提出了一种替代的难度调整算法。最后，我们评估了我们提出的方法，并展示了它的新算法如何比比特币的原始算法表现得更好。
The Bitcoin whitepaper [1] states that security of the system is guaranteed as long as honest miners control more than half of the current total computational power. The whitepaper assumes a static difficulty, thus it is equally hard to solve a cryptographic proof-of-work puzzle for any given moment of system history. However, the real Bitcoin network is using an adaptive difficulty adjustment mechanism.In this paper we introduce and analyze a new kind of attack on the mining difficulty retargeting function used in Bitcoin which we call “coin-hopping”. In a coin-hopping attack, a malicious miner increases his mining profits while at the same time increasing the average delay between blocks.We propose an alternative difficulty adjustment algorithm in order to reduce the incentive to perform a coin-hopping attack, and also decrease inter-block delays. Finally, we evaluate our proposed approach and show how its novel algorithm performs better than the original algorithm of Bitcoin.