Multiple Security Domain Nondeducibility for Point-of-care Diagnostic Technology: WiP Abstract

Microfluidics is an interdisciplinary science focusing on the development of devices and systems that process low volumes of fluid for applications such as high throughput DNA sequencing, immunoassays, and entire Labs-on-Chip platforms. Microfluidic diagnostic technology enables these advances by facilitating the miniaturization and integration of complex biochemical processing through a microfluidic biochip [1]. This approach tightly couples the biochemical operations, sensing system, control algorithm, and droplet-based biochip. During the process the status of a droplet is monitored in real-time to detect operational errors. If an error has occurred, the control algorithm dynamically reconfigures to allow recovery and rescheduling of on-chip operations. During this recovery procedure the droplet that is the source of the error is discarded to prevent the propagation of the error and the operation is repeated. Threats to the operation of the microfluidics biochip include (1) integrity: an attack can modify control electrodes to corrupt the diagnosis, and (2) privacy: what can a user/operator deduce about the diagnosis? It is challenging to describe both these aspects using existing models; as Figure 1 depicts there are multiple security domains, Unidirectional information flows shown in black indicate undesirable flows, the bidirectional black arrows indicate desirable, but possibly corrupted, information flows, and the unidirectional red arrows indicate undesirable information flows. As with Stuxnet, a bidirectional, deducible information flow is needed between the monitoring security domain and internal security domain (biochip) [2]. Simultaneously, the attacker and the operators should receive a nondeducible information flow. Likewise, the red attack arrows should be deducible to the internal domain. Our current security research direction uses the novel approach of Multiple Security Domain Nondeducibility [2] to explore the vulnerabilities of exploiting this error recovery process through information flow leakages and leads to protection of the system through desirable information flows.