Position on Securing-Workflow-Based Systems (Ph.D.)


Workflows are widely used by industry and government organizations to describe how data shall be processed and how actions shall be ordered. The individual tasks in a workflow might be performed by different actors (e.g., people, sensors, and servers), happen at different locations, and even span across multiple organizations. Consequently, securing workflows inherently involves distributed systems security and multi-lateral security (due to the different players). This makes the secure processing of sensitive data in work-flow-based systems a challenging problem.

Workflows can be used, for instance, to describe the steps in the manufacturing of a particular product (e.g., in Industry 4.0), organizational procedures (e.g., in hospitals), or strictly regulated procedures (e.g., in government organizations). Workflows appear in widely used modeling languages and computing paradigms (e.g., business processes in BPMN or BPEL, orchestrations in SOAs, and activity diagrams in UML). On a more conceptual level, a workflow can be viewed as a graph, where nodes correspond to tasks, and edges indicate control and data flow between tasks. Tasks can be constrained in multiple ways, e.g., which persons may perform a task, that at least two persons must perform the task jointly, or that some computation must run on a server under a company's control. Such constraints need to be respected when refining abstract tasks into more concrete ones for making a given workflow executable. The refinement of abstract tasks to executable programs becomes particularly intriguing when security requirements need to be preserved, due to the increased attack surface and due to the so called refinement paradox.

Our overall goal in this project is a framework for securing distributed implementations of workflow-based systems. We will provide support to automate the splitting of security requirements to local requirements for individual tasks that can then be directly implemented. We aim at reliable security guarantees and at lowering the costs of security by exploiting already available security mechanisms and characteristics of platforms.

The Position

In this position, you will develop solutions for refining abstract workflow specifications of systems to secure implementations. You will precisely describe security requirements for workflow-based systems, you will develop techniques for decomposing such global security requirements into local constraints for individual tasks, and simplify the use of these techniques by tools. Moreover, you will develop techniques for enforcing the local security requirements (e.g., by run-time monitoring or program transformations). Your research could build on established languages for describing workflows (e.g., BPMN or UML) and on frameworks for run-time monitoring (e.g., CliSeAu). Possible application domains include healthcare, industrial manufacturing (Industrie 4.0), and enterprise systems.

This position is associated with the project "Securing Refinements of Distributed Workflows" in the ATHENE Mission TRUDATA.

Prior Skills and Experiences

You should fit one of the following profiles (or a combination of both):
  • You should be interested in IT-security and have good software-development skills. In addition, prior knowledge is expected in at least one of modeling languages (e.g., BPMN, BPEL, or UML), construction paradigms for distributed systems (e.g., service-oriented architectures), program modifications (e.g., run-time monitoring or program transformations), or workflow-based systems. You should be willing and able to familiarize yourself with formal, logical foundations to the extent needed for specifying and decomposing security requirements.
  • You should be interested in IT-security and have a solid background in mathematics. In addition, prior knowledge in at least one of formal verification (theorem proving or model checking), formal modeling, or mathematical logic is required. You should be willing and able to familiarize yourself with workflow-based systems, their application domains, and relevant security requirements.
Finally, you should be highly motivated to tackle challenging research problems, to produce innovative insights and tools, to strive for international visibility as a researcher, and be open minded.

Formal Prerequisites

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