Computationally Secure Hierarchical Self-Healing Group Key Distribution for Heterogeneous Wireless Sensor Networks

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Computationally Secure Hierarchical Self-Healing
Group Key Distribution for Heterogeneous Wireless
Sensor Networks

• Y.J. Yang, J.Y. Zhou, R.H. Deng, F. Bao
• Institute for Infocomm Research, Singapore

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Agenda

• Introduction
• Heterogeneous WSN Architecture
• Basic Hierarchical Self-healing group Key
  Distribution Scheme
• Extended Scheme
• Conclusion

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• Introduction
• Heterogeneous WSN Architecture
• Basic Hierarchical Self-healing group Key
  Distribution Scheme
• Extended Scheme
• Conclusion

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Wireless Sensor Networks

• Wireless Sensor Networks (WSNs)

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Self-healing Group Key Distribution

• Key Distirubtion Management is Fundamental to
  Other Security Issues
• Pairwise key distribution
• Group key distribution
• Self-healing group key distribution especially
  suits WSNs lossy channel.

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Homogeneous WSNs

• All Existing Work Consider Homogeneous WSNs
• Homogeneous WSN
• All sensor nodes have the same capability
• Homogeneous WSNs have scalability problem.
  Theoretical and empirical studies have
  corroborated this

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Hierarchical Self-healing Key Distribution

• Motivated to Study Self-healing Group Key
  Distribution for Heterogeneous WSNs
• Hierarchical Self-healing Group Key Distribution
• Adapting to the heterogeneous WSN architecture

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• Introduction
• Heterogeneous WSN Architecture
• Basic Hierarchical Self-healing group Key
  Distribution Scheme
• Extended Scheme
• Conclusion

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Heterogeneous WSNs

• Heterogeneous WSNs Are A Better Alternative to
  Homogeneous ones
• The network is partitioned into groups, and each
  group is placed a group manager
• Group managers have better capability than sensor
  nodes
• A group manager acts an intermediary between
  sensor nodes and the base station

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Heterogeneous WSNs
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• Introduction
• Heterogeneous WSN Architecture
• Basic Hierarchical Self-healing group Key
  Distribution Scheme
• Extended Scheme
• Conclusion

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Key Hierarchy
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Key Generation
rK rk1, rk2
mKi mk1, mk2 h(Gi,rk1), h(Gi,rk2)
gKi
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Key Generation
reverse hash chain
foward hash chain
gKij kRm-j1kFj
kRj hRj(mk1) hR(hR(hR(hR(mk1)))) kFj
hFj(mk2) hF(hF(hF(hF(mk2))))
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Key Distribution
gKij kRm-j1kFj

• mk2 is given to each sensor as seed sF for the
  forward hash chain
• At the start of each session, the group manager
  generates kRm-j1 using mk1 as seed for the
  reverse hash chain, and broadcasts to sensors
  within its group
• The broadcast scheme is essentially the Dutta et
  al.s scheme, with a slight modification to
  rectify its weakness

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Key Distribution

• The reverse hash chain is used to achieve
  self-healing property
• The forward hash chain is used to achive forward
  secrecy, i.e., sensors joined later cannot
  compute group keys of earlier sessions

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• Introduction
• Heterogeneous WSN Architecture
• Basic Hierarchical Self-healing group Key
  Distribution Scheme
• Extended Scheme
• Conclusion

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Untrusted Group Manager
Untrusted Group Manager

• For the basic scheme, group managers are assumed
  trusted.
• However, group managers cannot be guaranteed
  trusted.
• We consider some group managers are compromised
  in the extended scheme

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Secret sharing of mk1
Secret sharing of mk1

• In basic scheme, if mk1 is compromised, all
  sessions are compromised
• We are left to secret sharing of mk1 among group
  managers and compute kRm-j1 in a distributed
  way
• The point is that hR() can be computed in a
  distributed way

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Choice of hR()

• Normal hash function cannot be used as hR()
• We define hR()
• hR() ZN ? QRN
• hR(x) x2 (mod N)

• mk1 is partitioned into t shares mk1
  s1.s2st-1.st (mod N)
• hRj(mk1) (s1)2j (s2)2j(st)2j (mod N)

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• Introduction
• Heterogeneous WSN Architecture
• Basic Hierarchical Self-healing group Key
  Distribution Scheme
• Extended Scheme
• Conclusion

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Conclusion
Conclusion

• Heterogeneous WSNs have better scalability and
  performance, as the introduction of powerful
  group managers provides shortcut for data
  transmission from sensors to base station

• We proposed hierarchical self-healing group key
  distribution tailored to heterogeneous WSNs

• Our constructions are based Dutta et al.s idea

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QA
Thank You!