  Mobile edge computing (MEC) systems (in which intensive computation and data
storage tasks are performed locally, due to the absence of communication
infrastructure for connectivity to the cloud) are currently being developed for
disaster response applications and for tactical environments. MEC applications
for these scenarios generate and process significant mission-critical and
personal data that require resilient and secure storage and sharing. In this
paper, we present the design, implementation, and evaluation of R-Drive, a
resilient data storage and sharing framework for disaster response and tactical
MEC applications. R-Drive employs erasure coding and data encryption, ensuring
resilient and secure data storage against device failure. R-Drive adaptively
chooses erasure coding parameters to ensure the highest data availability with
a minimal storage cost. R-Drive's distributed directory service provides a
resilient and secure namespace for files with rigorous access control
management. R-Drive leverages opportunistic networking, allowing data storage
and sharing in mobile and loosely connected edge computing environments. We
implemented R-Drive on Android, and integrated it with existing MEC
applications. Performance evaluation results show that R-Drive enables
resilient and secure data storage and sharing.
