  Modern cars are no longer purely mechanical devices but shelter so much
digital technology that they resemble a network of computers. Electronic
Control Units (ECUs) need to exchange a large amount of data for the various
functions of the car to work, and such data must be made secure if we want
those functions to work as intended despite malicious activity by attackers.
TOUCAN is a new security protocol designed to be secure and at the same time
both CAN and AUTOSAR compliant. It achieves security in terms of authenticity,
integrity and confidentiality, yet without the need to upgrade (the hardware
of) existing ECUs or enrich the network with novel components. The overhead is
tiny, namely a reduction of the size of the Data field of a frame. A prototype
implementation exhibits promising performance on a STM32F407Discovery board.
