  In recent years, the use and suitability of drones for many applications,
including surveillance, search and rescue, research, agriculture and civil
engineering, has greatly increased due to their improved affordability and
improved functionality. However, low-cost consumer drones are rarely designed
to work in fleets, which limits the applications for which business, research
and individuals may deploy such drones. Proprietary, commercial and bespoke
options are available at higher cost and existing solutions providing fleet
functionality have limited security, if any, which excludes their use for
sensitive applications. In this paper, we discuss the repurposing of consumer
off-the-shelf (COTS) drones for use in secured fleets and provide the design,
implementation and evaluation of a complete approach for creating end-to-end
secured fleets of consumer drones (SFCD).
  We present a protocol for securing communications within fleets whilst
employing more efficient symmetric key cryptography throughout to reduce the
impact of our security on the limited and resource-constrained COTS drones,
exploiting the characteristics of a fleet with an online and central ground
control station, which may act as a key distribution centre. The protocol
allows an arbitrary number of channels to be established to authenticate and
optionally encrypt real-time data transmitted on these channels. We also
discuss routing in fleets, as well as the control and monitoring of them, to
allow SFCD to be fully deployed; providing an extensive and thorough solution.
Our experimental evaluation confirms the suitability of low-cost consumer
drones for use in SFCD, with flight time impacted by only 9.9% and worst-case
bandwidth of 4.7Mibit/s.
