Security analysis is an essential activity in security engineering to identify potential system vulnerabilities and achieve security requirements in the early design phases. Due to the increasing complexity of modern systems, traditional approaches, which only consider component failures and simple cause-and-effect linkages, lack the power to identify insecure incidents caused by complex interactions among physical systems, human and social entities. By contrast, a top-down System-Theoretic Process Analysis for Security (STPA-Sec) approach views losses as resulting from interactions, focuses on controlling system vulnerabilities instead of external threats and is applicable for complex socio-technical systems. In this paper, we proposed an extension of STPA-Sec based on data flow structures to overcome STPA-Sec's limitations and achieve security constraints of information-critical systems systematically. We analyzed a Bluetooth digital key system of a vehicle by using both the proposed and the original approach to investigate the relationship and differences between both approaches as well as their applicability and highlights. To conclude, the proposed approach can identify more information-related problems with technical details and be used with other STPA-based approaches to co-design systems in multi-disciplines under the unified STPA process framework.

中文翻译：

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安全系统理论过程分析的基于数据流的扩展 (STPA-Sec)

安全分析是安全工程中的一项基本活动，用于识别潜在的系统漏洞并在早期设计阶段实现安全要求。由于现代系统日益复杂，传统方法只考虑组件故障和简单的因果关系，缺乏识别由物理系统、人类和社会实体之间复杂交互引起的不安全事件的能力。相比之下，自上而下的安全系统理论过程分析 (STPA-Sec) 方法将损失视为交互造成的，侧重于控制系统漏洞而不是外部威胁，适用于复杂的社会技术系统。在本文中，我们提出了一种基于数据流结构的 STPA-Sec 扩展，以克服 STPA-Sec' 系统的限制和实现信息关键系统的安全约束。我们通过使用提出的方法和原始方法来分析车辆的蓝牙数字钥匙系统，以研究两种方法之间的关系和差异以及它们的适用性和亮点。总而言之，所提出的方法可以通过技术细节识别更多与信息相关的问题，并与其他基于 STPA 的方法一起使用，以在统一的 STPA 流程框架下在多学科中协同设计系统。