DIANE Project

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Universität Karlsruhe GERMANY
Stimulating Cooperative Behavior of Autonomous
Devices An Analysis of Requirements and
Existing Approaches
The Second International Workshop on Wireless
Information Systems 22. - 23. April 2003
Angers, France
Philipp Obreiter, Birgitta König-Ries, Michael
Klein
Universität Karlsruhe Institute for Program
Structures und Data Organization
DIANE Project
http//www.ipd.uni-karlsruhe.de/DIANE
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Absence of Infrastructure
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Autonomy

• Autonomous devices
• devices are free to cooperate or not
• Sound assumption
• tampered devices
• re-engineered protocol stacks
• absence of an enforcing authority
• Devices tend to be uncooperative
• scarceness of resources (e.g. battery power)

? cooperative behavior must be stimulated
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Overview

• Cooperation and uncooperative behavior
• Issues for Incentive Schemes
• Existing Incentive Schemes

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Conceptual Layering
device A
device B
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Elementary Cooperation
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Taxonomy of Uncooperative Behavior
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Exemplification of Uncooperative Behavior
Drop other devices' advertisements ? selfish
behavior
Wastefully consume other devices' services ?
lavish behavior
User Interface
User Interface
Application
Application
Discovery
Discovery
Transport
Transport
Dropping packets under heavy load ? venial
noncooperation
Network
Network
Link
Link
DoS attack ? malicious behavior
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Incentive Schemes

• Incentive Scheme
• set of mechanisms that
• restrict misbehavior
• exempt venial noncooperation from punishment
• Current approaches for Ad Hoc Networks
• TermiNodes
• Sprite
• APE
• RPG
• Watchdog/Pathrater
• CONFIDANT
• CORE

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Issues for Incentive Schemes

• Trust
• Transactions
• Remuneration types

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Incentive Scheme Issues (1) Trust

• Trust
• prerequisite for remuneration mechanisms
• an incentive for cooperation
• Static Trust
• certification of an entity's trustworthiness
• requires cryptographic infrastructure
• Dynamic Trust
• arises from prior experiences
• need for reputation management
• considers behavioral change

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Incentive Scheme Issues (2) Transactions

• Transaction
• encompasses elementary cooperation
• agent executes action iff principal remunerates
  agent
• Negotiation phase
• agreement on the action and remuneration
• determined by the respective cost/profit ratios
• Processing phase
• assertion of atomicity seems daunting
• approximated atomicity
• by interleaving action and remuneration
• efficient low value transactions
• by aggregating actions and remunerations

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Incentive Scheme Issues (3) Remuneration

• Remuneration type
• different types have been proposed
• most popular types
• checks, e.g., TermiNodes
• reputation, e.g., Marti et al 2000
• Transferability
• passing on checks
• disseminating reputation
• Convertibility
• cashing checks
• reconciling user and device views of reputation

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Account Based Incentive Schemes Properties

• Remuneration mechanism
• every entity possesses an account
• accounts stored on virtual banks
• principal issues a check
• agent accesses a virtual bank in order to credit
  its account
• Implementation
• requires static trust mechanisms
• virtual banks managed by dedicated devices
• banker nodes
• accessibility?
• accounts distributed to account holders
• tamper resistant hardware

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Classification (1)
Approach Properties Approach Properties Approach Properties Termi- Nodes Sprite APE
Scope Coop. domain Coop. domain N/T N/T N
Scope Selfishness Selfishness yes yes yes
Scope Lavishness Lavishness yes yes yes
Scope Maliciousness Maliciousness yes - yes
Remuneration type Remuneration type Remuneration type checks checks checks
Transferability/ Dissemination Transferability/ Dissemination Transferability/ Dissemination yes - -
Convertibility Convertibility Convertibility - yes yes
Sniffing Sniffing Sniffing - - -
Trust Trust Trust static static static
Implemen-tation Implemen-tation Tamper resistance security modules - -
Implemen-tation Implemen-tation Cryptographic infrastructure public key public key public key
Trans-action Trans-action Negotiation yes - yes
Trans-action Trans-action Processing action/remuneration action/remuneration action/remuneration
Flex. remuneration Flex. remuneration Flex. remuneration yes yes yes
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Reputation Based Incentive Schemes Properties

• Remuneration mechanism
• principal adapts agent's reputation according to
  its action
• agent might decrease principal's reputation
• agent only cooperative if principal has good
  reputation
• Implementation
• couple trust and remuneration
• local views of reputation may be
• kept local
• shared, i.e., disseminated
• increases effectiveness
• introduces further opportunities for misbehavior
• requires stable or localized cooperation patterns

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Classification (2)
Approach Properties Approach Properties Approach Properties Termi- Nodes Sprite APE RPG Watchdog/ Pathrater CON- FIDANT CORE
Scope Coop. domain Coop. domain N/T N/T N N N N N
Scope Selfishness Selfishness yes yes yes yes - yes yes
Scope Lavishness Lavishness yes yes yes - - - -
Scope Maliciousness Maliciousness yes - yes - yes yes -
Remuneration type Remuneration type Remuneration type checks checks checks reputation reputation reputation reputation
Transferability/ Dissemination Transferability/ Dissemination Transferability/ Dissemination yes - - - yes yes only positive
Convertibility Convertibility Convertibility - yes yes - - - -
Sniffing Sniffing Sniffing - - - - yes yes yes
Trust Trust Trust static static static dynamic dynamic dynamic dynamic
Implemen-tation Implemen-tation Tamper resistance security modules - - - - - -
Implemen-tation Implemen-tation Cryptographic infrastructure public key public key public key - - - -
Trans-action Trans-action Negotiation yes - yes - - - -
Trans-action Trans-action Processing action/remuneration action/remuneration action/remuneration action/remuneration action/remuneration action/remuneration action/remuneration
Flex. remuneration Flex. remuneration Flex. remuneration yes yes yes - - - -
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Conclusion

• Summary
• cooperation beyond autonomy borders requires
  stimulation
• cooperation of protocol entities on different
  layers
• taxonomy and exemplification of uncooperative
  behavior
• discussion of incentive schemes
• trust
• transactions
• remuneration
• classification of existing approaches for ad hoc
  networks
• account vs. reputation based
• Future work
• incentive scheme for the discovery and
  application layer
• analysis of suitable remuneration types
• integration of incentive schemes

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Thank you!
Thank you for your attention!
More information on our project web
page http//www.ipd.uni-karlsruhe.de/DIANE/en
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Matching Remuneration Types to Layers