Talking To Strangers: Authentication in AdHoc Wireless Networks

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Talking To StrangersAuthentication in Ad-Hoc
Wireless Networks

• Presenter Phu Dinh

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Outline

• Introduction
• Related Works
• Preliminaries
• Basic Protocol
• Alternative Protocols
• Group Key Exchange Protocols
• Conclusion and Future Work

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Introduction

• Problem
• - Securely and Authentically Communication
  with any ad-hoc device
• Certificate Authority?
• - Public Key Infrastructure Impractical
  Expensive
• - Finding the Device Name Not Reliable
• - Universal Naming Scheme Not User-Friendly

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Related Work

• Out-of-Band Authentication
• - Phone, Mail, Face-to-Face
• Bluetooth and WEP
• - PIN and Link Layer Security
• Resurrecting Duckling Security Model
• - Master/Slave (Mother/Duckling)

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Preliminaries

• Location-Limited Channels
• Used for Pre-Authentication
• Properties
• - Support Demonstrative Identification
• . Based on Physical Context
• - Authenticity
• . Protect from Potential Active Attackers
• - No Secrecy
• . Resistant to Passive Attackers
• Physical Media
• Contact, Infrared, Sound, etc.

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Preliminaries contd

• Public Key Cryptography
• Remove Secrecy Requirement
• - Secure Against Passive Attacks
• - Active Attacks Are Easily Detected
• Use of Hash Functions

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Basic Protocol

• Public Key Operations at Both Ends

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Basic Protocol contd

• Note
• - Security does not rely on the correctness
  of the device address.
• - However if provide wrong address, both
  devices cant complete the authentication process

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Alternative Protocols

• Single Public Key Protocol
• - When only one of the devices has resource for
  expensive public key operation
• Interactive Guy Fawles Protocol
• - Public key operation are infeasible for both
  ends

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Single Public Key
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Interactive Guy Fawles Protocol
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Group Key Exchange Protocols

• Centrally Managed Groups
• Unmanaged Groups.

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Centrally Managed Groups
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Centrally Managed Group contd

• Problem
• Since any node can become the group manager
• - Single Point of Attack
• - Group Manager leaves the group

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Unmanaged Groups
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Conclusion

• Use of Location-Limited Channels
• Novel Location-Limited Channels
• Concrete Pre-Authentication Protocols
• Group Communication
• No Reliance on PKI

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Future Works

• Physical Media for Location-Limited Channels
• Discover New Media
• Determine Optimal Media
• Determine Any Vulnerabilities and Fixes
• Further Implementation Development
• - Constructing Contact-Mediated Interface
• - Expand to Group Authentication with Audio

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End

• Questions?