TAODV: A Trusted AODV Routing Protocol for MANET

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TAODV A Trusted AODV Routing Protocol for MANET

• Li Xiaoqi, GiGi
• March 22, 2004

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Outline

• Introduction
• Framework of Truman (TRUsted MANETs)
• Trust model for Truman
• Routing operations in Truman
• Analysis
• Conclusion and future work

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Introduction

• Mobile Ad Hoc Networks (MANETs)
• No fixed infrastructure
• Self-organized multi-hop routing among nodes
• Nodes with high mobility
• Underlying wireless communication medium
• Frequent link layer errors
• Vulnerable to kinds of attacks

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Applications of MANETs

• Personal area networking
• Meeting rooms
• Disaster relief
• Battlefield operations

? High Security Requirements
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Previous Security Solutions for MANET

• Secure routing protocols
• may perform digital signature authentication at
  each routing message
• huge overhead
• Key management mechanisms
• usually need a super-trusted third-party to issue
  certificates
• destroy the self-organization nature of MANETs

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Basic Idea of Truman

• A secure routing protocol for MANETs
• Make use of trust relationships among nodes
• Design a trust model derived from subjective
  logic
• Need not sign and verify digital signature at
  each routing message
• Cooperate with a self-organized key management
  mechanism, such as some threshold solutions
• More scalable and robust

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Framework of Truman
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Review of Our Trust Model

• Use Opinion to represent trust
• Discounting Combination
• Combine trusts along one path
• Consensus Combination
• Combine trusts from several paths
• Mapping from evidence space to opinion space

p positive evidences n negative evidences
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Routing Operations in Truman

• Trust Recommendation
• Route Table Extension
• Trust Judgement
• Trust Update
• Routing Messages Extensions
• Trusted Routing Discovery

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Trust Judgement
b belief d disbelief u
uncertainty 0.5 threshold
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Trust Update

• Update trust from local evidences
• Successful Communication ?Positive events p
• Failed Communication ?Negative events n
• Update trust from trust combination
• Combination from different recommendations
• Trust update algorithm
• TWeTeWcTc
• Usually WegtWc
• Update fashion
• Periodical update if high packets frequency
• On-demand update if lower packets frequency

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Routing Messages Extensions

• Add such fields into original routing messages
• Trust information, or
• Digital signature information
• RREQ ? TRREQ
• RREP ? TRREP
• Message structure
• original routing information,
• trust information/signature information

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Trusted Routing DiscoveryScenario I-Beginning
of Truman

• Pre-operations
• Each node in this network has generated its own
  secret, public key pair and obtained the public
  keys of other nodes for further usage of digital
  signature.
• Each nodes opinion towards others is (0,0,1),
  which means total uncertainty of other nodes
  trustworthiness.

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Trusted Routing DiscoveryScenario I-Beginning
of Truman (cond)

• A broadcasts RREQ to discover C
• B is uncertain about A ? request A to sign itself
• A unicast RREQA
• B verifies it using PA . If pass, broadcast
  RREQB
• C has PB, verify it and reply RREPC
• B has PC, verify it and forward RREPB
• A has PB, verify it and begin data communication

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Trusted Routing DiscoveryScenario I-Beginning
of Truman (cond)

• During the initialization period, nodes perform
  digital signing and verification at each routing
  message
• If a node A has passed Bs verification, B will
  update its local route table (route path and
  trust value) in a certain update fashion.
• After first routing communication, the opinions
  are all changed to (0.33,0,0.67)
• Still high computation overhead in the beginning.

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Trusted Routing Discovery Scenario II-A Stable
Truman
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Performance Analysis

• Communication overheads can be sharply reduced by
  avoiding signature generation and verification at
  each routing message.
• Bandwidth overheads can be largely reduced
  because of replacing 1024/2048 bit signatures to
  simple trust values.

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Security Analysis

• If no misbehavior, trust value will keep
  increasing.
• If an external malicious node, it will at once be
  denied due to not providing valid signature.
• We only consider to prevent external attacks.
• Internal attacks can be eased through
  certificates renewal.

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Conclusion and Future Work

• Truman is a trusted MANET which employs two types
  of security solutions
• A trusted routing protocol
• A self-organized key management mechanism
• Light computation overheads and a certain
  security level guarantee.
• Perform simulation to proof it.

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QA

• Thank You!