1. Veronica Eyo Sharvari Joshi

3. The nodes are left unattended An Adversary can physically compromise the nodesSolution?  Authentication and cryptographic mechanisms alone can not solve this problem  The trust system was used for security in the Wireless sensor network

4.  These systems identify malicious nodes, computes a trust rating of the node and exclude the nodes from the network.

5.  First trust based model designed and developed for sensor networks.  It makes use of the watchdog mechanism to collect data and monitor different events going on in the node, to build reputation(R ij )of the node and then get the trust rating (T ij )of the node.

6. T ij = P j + 1 P j + N j + 2 P j = Positive outcome N j = Negative outcome RFSN can not distinguish between negative and positive events in the node.

7. Addressed the uncertainty issue but still cooperated with the malicious nodes. Has one value of trust rating for different events.

8. Event based trust framework is proposed to detect malicious sensor nodes A new protocol ESTN is developed A new direction in trust system for wireless sensor network is proposed

9.  The trust rating is dependent on different events in the node  Each event on the sensor node has a different trust rating  A sensor node has several trust ratings stored in its neighbor nodes

11.  The agent node  Classifies all the events and then builds a reputation table of the nodes  A trust table is then computed from the reputation table and broadcast to all the nodes.

12.  Event E happened in sensor nodes.  Let E={e 1,e 2,e 3,....e n }  Event function.  F={F(e i )| ∀e i ∈E,F(e i ) ≥1,F(e i )∈N}  Positive outcome p i  Negative outcome n i  is binary event for a certain event e i of sensor node.

13.  Define reputation space of event e i  RS(e i )={ |t i =p i +n i ;p i =F(e i ) or n i =F(e i ) ∀e i ∈E}  P (x)= (p i +n i +1)! X i ^(p i ) (1-X i )^n i p i ! n i !

14.  Reputation:  Reputation: opinion of one entity about another  Trust:  Trust: Expectation of one entity about another.  Reputation space to Trust space  Let T i ( )=(pt i,nt i,ut i ) be the transformation from binary event to trust rating (pt i,nt i,ut i )

15.  while True  For all the nodes s and t in the agent node radio  range  For event e1 to en  Agnet node gets the binary event  Agent computes the trust rating Tsti;  If (Tsti) < a certain value  Break;  End if  End for  The agent broadcasts the trust rating Tsti;  End for  If the time is the begin of window time  The agent broadcasts all the trust rating Tsti;  End If  End While

16.  Modules used: ◦ Wireless sensor networks (x A, x B …x N ) ◦ Agent nodes (x i ) ◦ Intruder nodes (x m ) ◦ Traffic data (  ) ◦ Events generator

20.  Need to design a special Agent node  Higher processing power for the agent node  Complex architecture  Protection of agent node

21.  Protect agent node from discovery.  Broadcast trust rating to the remote monitoring facility.

22.  This trust model can be used in large scale wireless networks  It provides a more accurate guarantee along with cryptographic mechanisms in detecting malicious nodes of different events in sensor networks

23.  Questions?