Trust Evaluation Based Security Solution in Ad Hoc Networks

1
Trust Evaluation Based Security Solution in Ad
Hoc Networks

• Zheng Yan
• Nokia Research Center
• NordSec 2003
• ???

2
Content

• Security Problem in Ad hoc Network
• Related Work
• Trust Evaluation Based Security Solution
• Secure Routing Based on Trust Evaluation
• Discussion
• Conclusion

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Ad hoc net characteristics

• No trusted third party autonomous
• Dynamic no fixed trust
• gt Decentralized trust (Security by itself)

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Trust evaluation based security solution

• Compare
• Result of trust Evaluation of other node
• with
• threshold (defined policy )
• ,then do or do not

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Trust modeling

• Trust
• The confidence of an entity on another entity
  based on expectation that the other entity will
  perform a particular action important to the
  trustor
• Trust Modeling
• A technical approach to represent trust for
  digital processing

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Trust model

• Personal Trusted Bubble
• the basic unit in which the owner of the adhoc
  device has illogically full trust on device
• Trust relationship
• Among bubbles and btw the bubbles and the fixed
  networks, logical and rational trust relationship
  should be evaluated computationally

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Trust models

• Independent Model
• Cross Model

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Trust matrix

• Trust Evaluation Matrix in each bubble

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Factors(1/3)

• Experience statistics
• if communication success , increase
• if fail, decrease
• Ves(i,j) FES (Proportion of success
  communication)
• Data value
• the value of communication data
• Vd(i,j)FD(importance of data transferred)
• Intrusion black list
• Vibl(i,j) 1/0 (1Good, 0 Bad)

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Factors(2/3)

• Reference
• other bubbles recommendation, reputation,
  intrusion detection report
• Vr(I,j)FR(other PTBs recommendation on
  B(j), reputation of
• B(j), ..)
• Personal preference
• bubble owners preference
• rx(i,j,a)Fr(prefered rate of B(i) on x
  factor on B(j) on action
• a)

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Factors(3/3)

• Other factor
• frequency of routing request from a node
• Vo(i,j) FO(frequency of routing request from
  B(j))
• PTB policy
• Threshold policy
• Vp(i,j,a) Fp(B(i)s security policy on B(j))

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Metric

• TEa(I,j) trust evaluation result by B(i) on
  B(j) for action a
• TEa(I,j) res(i,j,a)Ves(i,j)
  rd(i,j,a)Vd(i,j) rr(i,j,a)Vr(i,j)
  ro(i,j,a)Vo(i,j) Vibl(i,j)
• ,where ? rx(i,j,a) 1 (xes, d, r, o)

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Example

• Secure routing
• Route select decision based on trust evaluation
• Dynamic update of trust evaluation matrix

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Routing Request
1. Source broadcast RREQ 2. Neighbor forward
based on trust evaluation
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Routing Request
3. Respond RREP 4. Choose route based on trust
evaluation
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Data confirmation from destination node
5. Source send test data package 6. Destination
confirm
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Depending attacks

• Black hole attack
• Malicious node advertise itself as the shortes
  path
• Confirmation message within time slot
• Confirm message route different from test message
• Randomly sent confirm message
• Denial of service
• If the frequency of RREQ exceeds threshold,
  ignore it
• Broadcast intrusion
• Routing table overflow or energy consummation
• Attacker create route to nonexistent node
• Attacker request frequent forwarding
• Ignore or reject according to trust evaluation

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Discussion

• Security level be closing to correctness
  gradually

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Conclusion

• Introducing human beings social contact
  procedure
• Secure source initiated on-demand driven routing
• Gradual security solution which can achieve
  expected security level