Using covert timing channels for attack detection in MANETs

Mobile ad hoc networks (MANETs) are notoriously difficult to defend against attack. In this paper we demonstrate that by optimizing a previously reported covert timing channel, it is possible to simultaneously improve the reliability of the channel and create a metric that reliably detects attacks. Using standard methods from information theory, we compute the capacity of the covert channel and show that it is reduced under wormhole attack. This result leads us to a novel application of error-correcting codes to our covert channel, where the number of errors corrected provides a measure of the likelihood that a route traverses a wormhole. This technique does not use any of the bearer-channel communications bandwidth nor does it require modifications to the protocols or hardware.