Trust and Reputation Based mechanisms for CIP Uniparthenope, UniRC, Polito (Fai della Paganella, Febbraio 2014)

Objectives To enhance the cyber security of Wireless Sensor Networks (WSNs) deployed to protect CIs by exploiting Trust and Reputation Model based techniques – Intrusion Tolerance at the routing level

Security of WSNs WSNs have low computational resources and energy supply – Limit the number of exchanged messages – Limit the usage of cryptographic mechanisms WSNs are deployed in unattended, hostile, environments

Trust and Reputation A trust and reputation model is proposed to improve cyber defense. Say Node 3 wants to estimate trust and reputation perceived about Node 2: Node 3 estimates a trust score of Node 2 through a direct measure related to Node 2 Node 3 estimates a reputation score of Node 2 through indirect measurements, e.g. by observing the trust level perceived by Node 1 wrt Node 2

Attack Model: Sinkhole Attack Trust and reputation-based scores to ensure resilience against attacks such as sinkhole No attack Node 3 successfully attacks (BS = Base Station)

Trust and Reputation Model The model proposed acts as follows: 1.When Node 3 starts an attack, by pretending to have the best route toward destination, we need: 1.A reliable way to check if it is lying (to measure trust) 2.A way to share this information (to update neighbourns reputation) (BS = Base Station)

Test of Trustworthiness Assuming to have a routing protocol enabling parties authentication 1.Node 4 forces a ping through two alternate paths one of which includes the node under test 2.Node 4 chooses the route with lower round trip time 3.If the selected path does not use the tested node as gateway the trust level of node 3 is lowered – T 43 (t+1) = k* T 43 (t) k < 1 3

Reputation If a change in the trust level of node 3 is going to occour, node 4 forwards a feedback to each of the nodes in its neightbour list. Each node receiving the feedback accordingly corrects the reputation of node 3 – R i3 (t+1) = f(R i3 (t), ΔT 43 )

Intrusion Tolerance When a node must select a parent to reach the BS this evaluation will be based on: quality of the channel, trust level, and reputation level of the candidate node. – That is a Dependability function is evaluated for each candidate and the new parent will be the one with highest dependability value: For each j in N: D ij (t+1) = f(Q ij (t), T ij (t),R ij (t)) (N set of neighbours) The node j such that D ij (t+1) =Max(Dij(t+1)) is selected as the parent one

AODV Routing Protocol Ad hoc On Demand Distance Vector (AODV) is a standard routing protocol defined by RFC 3561 ( AODV is widely adopted e.g. in Bluetooth and Zigbee

Implementation A WSN was simulated through NS-3 NS3 is a command-line, open source (GNU GPL v2) network simulator Programming languages: C++, Python Different WSNs routing protocols are implemented such as Optimized Link State Routing Protocol (OLSR) and Ad hoc On Demand Distance Vector (AODV)

Future Steps To complete implementation To test the effectiveness of the proposed model under different testbed configurations, and parameters tuning To extend the approach to manage other kind of attacks