An Efficient Group Key Generation

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An Efficient Group Key Generation in the
Battlefield
Jin Wook Byun byunstar_at_korea.ac.kr CIST GSIS,
Korea University
Nov. 16. 2005
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Contents

• Multi-layer ad hoc Network (Battlefield)
• Password-based key exchange protocols
• An efficient Group Key Generation in Battlefield
• Conclusion

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Multi-layer Ad-hoc Network

• Multi-layer Ad-hoc Network
• Ground MANET
• Includes regular ground mobile nodes (GN)
• GN is equipped with limited powers.
• Ground mobile backbone network
• Includes special fighting nodes such as tanks.
• Tanks may carry a lot equipment than soldiers.
• Unmanned aerial vehicles (UAV)
• UAV maintains a station that at an altitude of
• 50 thousands feet by flying a circle.

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Motivation Contributions

• Motivations
• Second and third layers gt the first layer
• Communicational and computational power !!
• The first Ground MANET
• Various physical attacks and bombs with dynamic
  changing network configuration
• Lightweight, convenient, and secure cryptographic
  solutions should be applied to soldiers
• N-Party EKE-D Protocol
• Constant round - lightweight
• Distinct Human-memorable passwords - convenient
• Dynamic setting - MANET

Battlefield !!
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Password-based Key Exchange

• Goal
• Confidentiality, Integrity
• Application
• Building secure communications in cryptographic
  protocols such as IPSec, SSL.
• Password-based Key Exchange (PAKE)
• Shared Password-Authenticated Model
• Provides PAKE between a client and server using
  shared password
• Different Password-based Authenticated Key
  Exchange (DPWA)
• Provides PAKE between a client and a client using
  different passwords

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Password-based Key Exchange

• Brief History in this area
• Different Password- Authentication Model (DPWA)
• Two party
• 1995, Steiner et al. 3-Party EKE
• 1998, Lin et al. LSSH-3PEKE
• 2002, Byun et al. C2C-PAKE
• 2005, Byun et al. efficient and provably secure
  C2C-PAKE
• 2005, Abdalla et al. Generic construction of a
  3-party protocol
• N-party
• 2005, Byun et al. suggested N-party EKE protocols
• 2005, Byun et al. suggested N-party EKE secure
  against insider attacks.

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Model and Definition

• NEKE Security
• Assumption
• Computational Diffie-Hellman Assumption

Asks queries
Test Query
Coin toss b If b1, real sk?SK Else, random str?SK
SK
Guess b
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N-party EKE-D

• Setup Algorithm

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N-party EKE-D

• Leave Algorithm

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N-party EKE-D

• Join Algorithm

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Security Results

• N-party EKE-D
• of send, hash, enc/dec queries
• Forward Secrecy
• Backward Secrecy

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Conclusion

• N-Party EKE-D
• Different passwords
• Constant round
• Provable security
• Dynamic scenario
• On Going works
• We are now designing a general key management
  framework covering all layers of Multi-layer
  ad-hoc networks

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Thank you very much !!Q AE-mail address
byunstar_at_korea.ac.kr