Transfer and enhancement of information-flow control techniques to develop secure systems using the example of workflow systems (MORES2)

MORES2项目继续发展了一个框架，用于开发从前一个项目MORES开始的安全工作流系统。MORES从事工作流系统安全属性的建模和验证，在特定抽象级别考虑不同类型的请求安全属性（例如信息流控制、职责分离），并提供各种分解技术。现在，MORES2的目标是为这些工作流规范开发适当的细化技术。特别是，要开发的精化概念必须支持工作流的各个方面（例如活动、数据、用户）的精化，还必须能够将MORES中考虑的安全属性转换为其他精化级别中的相应属性。较高抽象级别的翻译安全保证将作为较低级别安全属性验证的初始构建块。然而，我们不能期望改进的概念将在一般情况下保留安全保证，因为否则产生的限制将使这种改进变得不切实际。此外，更改抽象级别还可能导致攻击者观察工作流的能力的细化，从而导致所需要的安全保证的表述方式发生变化。在MORES2中，我们将开发一些技术，利用更高抽象级别的安全保证来验证较低抽象级别上相应的安全属性。我们将基于现有的交互式证明系统提供相应的验证工具支持。将MORES2即将发布的结果与MORES中开发的分解技术相结合，我们将提供一种支持工作流系统整体安全的集成方法。应用分解技术减少了要验证的组件的大小，并在一般情况下提高了验证任务的可伸缩性。细化技术允许重用较高抽象级别的安全保证来验证较低级别的安全性，从而简化证明任务。将使用优先级程序的基于web的工作流管理系统中的参考场景安全性来评估此方法，方法是在不同的抽象级别上指定它，并使用它来举例说明沿着细化层次结构产生的安全属性的转换。

The project MORES2 continues the evolution of a framework for developing secure workflow systems started in the predecessor project MORES. MORES was engaged in the modeling and verification of security properties for workflow systems considering the different types of requested security properties (e.g. information-flow control, separation of duty) at a particular level of abstraction, providing various decomposition techniques. Now, MORES2 aims at the development of appropriate refinement techniques for these workflow specifications. In particular, the notion of refinement to be developed has to support the refinement of the various aspects (e.g. activities, data, users) of workflows and also has to be able to translate the security properties considered in MORES to corresponding properties in other refinement levels. Translated security guarantees of higher abstraction levels will serve as initial building blocks for the verification of security properties on lower levels. However, we cannot expect that the notion of refinement will preserve the security guarantees in general because otherwise the arising restrictions would render such a refinement impracticable. Additionally, changing the abstraction level may also result in a refinement of the abilities of an attacker observing the workflow, which causes a change of how the required security guarantees are formulated. In MORES2 we will develop techniques to make use of security guarantees of higher abstraction levels in verifying the corresponding security properties on lower abstraction levels. We will provide a corresponding verification tool support based on existing interactive proof systems.Combining the upcoming results of MORES2 with the decomposition techniques developed in MORES, we will provide an integrated approach supporting security-in-the-large for workflow systems. Applying the decomposition techniques reduces the size of the components to be verified and improves the scalability of the verification tasks in general. The refinement techniques allow one to reuse the security guarantees of higher abstraction levels to verify the security of lower levels resulting in simpler proof tasks. This approach will be evaluated using the reference scenario Security in Web-based Workflow Management Systems of the priority programme by specifying it on various abstraction levels and using it to exemplify the translation of the arising security properties along the refinement hierarchy.