Modelling the Supply Chain: Trust but Verify in Complex Systems

Trust, but verify is a Russian proverb that has reverberated throughout history. Trust involves a belief in the fidelity of what is being evaluated. But fidelity can fluctuate, making trust more accurately characterized as varying rather than binary. This concept is especially true in the operation and evaluation of complex systems. The volume of operation and interconnectivity of states in complex systems can create unanticipated effects, and the resiliency of such systems is dependent on communicating degradation and collapse, and correcting unanticipated failure as it occurs. Supply chains are complicated systems of systems that operate within an increasingly complex global environment. They involve the interconnection of multiple systems, independently owned and often optimized with different, competing priorities. The degradation of trust in these systems can have profound consequences in the complicated environment, and the disruption of this environment may result in behaviors that exhibit characteristics associated with complexity. Disruption of trust may be an intentional objective; supply chains are critical, complicated and increasingly automated and technology assisted, which makes them a focal point for sufficiently advanced adversaries. This effort serves as an assessment of how trust in the supply chain may be potentially degraded due to environmental complexity. This is achieved through merging the disciplines of trust engineering, systems engineering and dependency modelling to form a lens through which the impact of complexity on supply chain trust can be evaluated. Fundamentally, there is a requirement for trustworthy, verifiable and reliable systems within supply chains, and cyber security measures must be taken in order to ensure this trustworthiness.