  Since Remote Keyless Entry (RKE) systems started to be widely used, several
vulnerabilities in their protocols have been found. Attacks such as
jamming-and-replay attacks and relay attacks are still effective against most
recent RKE systems, even when many secure schemes have been designed. Although
they are interesting from a theoretical point of view, the complexity of these
solutions is excessive to implement them into a fob. This paper presents a
lightweight and general solution based on a one message protocol, which
guarantees the integrity and validity of the authentication in RKE systems,
protecting the communication against the well-known jamming-and-replay and
relay attacks, without using complex cryptographic schemes. Moreover, we also
adapt our protocol for passive RKE (PRKE) systems. Our solution also includes a
novel frequency-hopping-based approach which mitigates deny-of-service attacks.
Finally, a prototype has been implemented using non-expensive hardware.
Obtained results assure scalability, effectiveness and robustness.
