Blockchain has arisen as a revolutionary technology to provide trust in scenarios where several independent agents must agree about certain information. This characteristic makes Blockchain the perfect technology to operate with future next-generation internet applications, especially when involving critical data. However, assumptions and conditions that make Blockchain a secure technology are not usually considered, so many popular and recent Blockchain-supported proposals (such as only-one-miner solutions) are unsecure in practice due to Blockchain intrinsic vulnerabilities and other technology limitations. In particular, most of these solutions are vulnerable to a novel and unstudied cyberattack: Denial of Chain (DoC). Therefore, in this paper this new cyberattack is defined and studied from a theoretical and experimental point of view. Besides, a framework to predict the occurrence of this new attack is also described. A mathematical model to represent blocks and chains in Blockchain solutions is proposed, and it is employed to create a statistical framework to analyze the novel DoC attack. Simulation instruments (such as Multichain simulators) and real hardware nodes (based on Raspberry Pi computers) are employed to validate the proposed model and framework, and the proposed solutions.

区块链已经成为一种革命性的技术，可以在几个独立的代理必须就某些信息达成共识的情况下提供信任。这一特性使Blockchain成为与未来的下一代Internet应用程序一起运行的理想技术，尤其是在涉及关键数据时。但是，通常不会考虑使区块链成为安全技术的假设和条件，因此由于区块链固有的漏洞和其他技术局限性，许多流行和最新的区块链支持的提案（例如仅一个矿工的解决方案）在实践中都不安全。尤其是，这些解决方案中的大多数都容易受到新颖而未经研究的网络攻击：拒绝链（DoC）。因此，本文从理论和实验的角度定义和研究了这种新的网络攻击。除了，还描述了预测这种新攻击发生的框架。提出了一种代表区块链解决方案中的区块链的数学模型，并将其用于创建统计框架来分析新型DoC攻击。仿真工具（例如Multichain模拟器）和真实的硬件节点（基于Raspberry Pi计算机）被用来验证所提出的模型和框架以及所提出的解决方案。