Security Assessment of Micro-Electrode-Dot-Array Biochips

Digital microfluidic biochips (DMFBs) are versatile, reconfigurable systems for manipulating discrete fluid droplets. Building on the success of DMFBs, platforms based on "sea-of-electrodes," the micro-electrode-dot-array (MEDA), has been proposed to further increase scalability and reconfigurability. Research has shown that DMFBs are susceptible to actuation tampering attacks which alter control signals and result in fluid manipulation; such attacks have yet to be studied in the context of MEDA biochips. In this paper, we assess the security of MEDA biochips under such attacks, and further argue that it is inherently a more secure platform than traditional DMFBs. First, we identify a new class of actuation tampering attacks specific to MEDA biochips: the micro-droplet attack. We show that this new attack is stealthy as it produces a subtler difference in results compared to traditional DMFBs. We then illustrate our findings through a case study of an MEDA biochip implementing a glucose measurement assay. Second, we enumerate the system features required to secure an MEDA biochip against actuation tampering attacks and show that these features are naturally implemented in MEDA.