  We present VoltKey, a method that transparently generates secret keys for
colocated devices, leveraging spatiotemporally unique noise contexts observed
in commercial power line infrastructure. VoltKey extracts randomness from power
line noise and securely converts it into an authentication token. Nearby
devices which observe the same noise patterns on the powerline generate
identical keys. The unique noise pattern observed only by trusted devices
connected to a local power line prevents malicious devices without physical
access from obtaining unauthorized access to the network. VoltKey is
implemented inside of a standard USB power supply as a platform-agnostic
bolt-on addition to any IoT or mobile device or any wireless access point that
is connected to the power outlet.
