# Veronica Eyo Sharvari Joshi

Λογισμικό & κατασκευή λογ/κού

13 Δεκ 2013 (πριν από 4 χρόνια και 6 μήνες)

112 εμφανίσεις

Veronica Eyo

Sharvari Joshi

The nodes are left unattended

An Adversary can physically compromise the nodes

Solution?

Authentication and cryptographic mechanisms alone
can not solve this problem

The trust system was used for security in the Wireless
sensor network

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

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.

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.

still cooperated with the malicious
nodes.

Has one value of trust rating for
different events.

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

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

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.

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

<p ,n > is binary event for a certain event e
i

of sensor node.

Define reputation space of event e
i

RS(e
i

)={<p
i

,n
i
>|t
i
=p
i
+n
i
;p
i
=F(e
i

) or n
i
=F(e
i

)
∀e
i
∈E}

P<p
i

n
i
> (x)=
(p
i
+n
i
+1)! X
i

^(p
i
) (1
-
X
i
)^n
i

p
i
! n
i
!

Reputation:
another

Trust:
another.

Reputation space to Trust space

Let T
i

(<p
i

,n
i

>)=(pt
i

,nt
i

,ut
i

) be the
transformation from binary event <p
i

,
n
i

> to
trust rating (
pt
i

,
nt
i
,ut
i

)

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 <pi ,ni >

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

Modules used:

Wireless sensor networks (x
A
, x
B
…x
N
)

Agent nodes (x
i
)

Intruder nodes (x
m
)

Traffic data (

)

Events generator

Need to design a special Agent node

Higher processing power for the agent node

Complex architecture

Protection of agent node

Protect agent node from discovery.

Broadcast trust rating to the remote
monitoring facility.

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

Questions?