• networking
• sensori
• sicurezza
• tsch

In this thesis we focus on an important security aspect of wireless sensor/actuator networks using the IEEE 802.15.4e Time Slotted Channel Hopping (TSCH) protocol.
Despite one of the main reasons of introducing TSCH was just the safety aspect, this presents some problems caused by its deterministic nature. We show why that, and we prove that selective jamming represents a concrete problem thanks to its simplicity and velocity.
We inspect IEEE 802.15.4 and 802.15.4e standards in order to understand if security could be a solution and what is possible to acheive by means of it. We show that this doesn't represent a big issue for a malicious node, which can reach its goal spending a feasible amount of time and energy even if security were implemented. We present such kind of attack, algorithm used and impact on a TSCH network, by means of both simulative tests and on real-environment.
Finally we propose a feasible solution to significantly reduce the problem of selective jamming, maintaining basic characteristics of TSCH. It consists of changing links schedule at every slotframe, thus making the used channel unpredictable to the adversary. This system is decentralized, as sensor nodes determine the next schedule in a distributed and autonomous way.