Security analysis of blockchain technology is an active domain of research. There has been both cryptographic and game-theoretic security analysis of Proof-of-Work (PoW) blockchains. Prominent work includes the cryptographic security analysis under the Universal Composable framework and Game-theoretic security analysis using Rational Protocol Design. These security analysis models rely on stricter assumptions that might not hold. In this paper, we analyze the security of PoW blockchain protocols. We first show how assumptions made by previous models need not be valid in reality, which attackers can exploit to launch attacks that these models fail to capture. These include Difficulty Alternating Attack, under which forking is possible for an adversary with less than 0.5 mining power, Quick-Fork Attack, a general bound on selfish mining attack and transaction withholding attack. Following this, we argue why previous models for security analysis fail to capture these attacks and propose a more practical framework for security analysis pRPD. We then propose a framework to build PoW blockchains PRAGTHOS, which is secure from the attacks mentioned above. Finally, we argue that PoW blockchains complying with the PRAGTHOS framework are secure against a computationally bounded adversary under certain conditions on the reward scheme.
翻译:安全链技术的安全分析是研究的一个积极领域。 已经对工作证明(POW)链块进行了加密和游戏理论安全分析。 突出的工作包括在通用综合框架下进行加密安全分析, 以及使用合理协议设计进行游戏理论安全分析。 这些安全分析模型依赖于可能无法维持的更为严格的假设。 在本文中, 我们分析POW链块安全协议的安全性。 我们首先展示了以往模型的假设在现实中如何不需要在现实中有效, 攻击者可以利用这些模型无法捕捉的攻击来发动这些攻击。 其中包括困难交替攻击, 在这种攻击下, 以不到0. 5 5 的采矿能力对敌进行隐蔽安全分析, Quick- Fork 攻击, 以自私的采矿攻击和交易缓冲攻击为主。 之后, 我们争论为什么以前的安全分析模型不能捕捉到这些攻击, 并为安全分析 pRPPPDD 提出更实用的框架。 我们然后建议建立一个框架, 以建造POW块链, PRAGTHOS, 不受上述攻击的危害。 最后, 我们争论说, PoW区链在一定的税制下, 在PRAGTOS 上进行安全的升级。