Security in Self-organizing Systems

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Security in Self-organizing Systems
Refik Molva Institut EURECOM refik.molva_at_eurecom.f
r http//www.eurecom.fr/ce/researchce/nsteam.en.ht
m
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Self-organizing Systems

• System or Network consists of a Collection of
  Ordinary Components
• No fixed infrastructure
• No (or limited) organization
• Ad Hoc Networks
• Sensor Networks
• P2P Applications
• Ubiquitous computing

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Security Challenges

• Comm. Security

• Self-organizing
• No(or limited) infrastructure
• Lack of organization
• Wireless Mobile
• Scarcity of Resources
• Limited Energy
• Lack of physical security
• Lack of connectivity

• Key management

• Trust Management

• Cooperation

• Privacy

Context-awareness
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Communication Security

• Secure Routing
• ARAN, SRP, ARIADNE, SEAD,TIK
• New Challenges
• Network coding and security Gkantsidis,
  Rodriguez
• Data aggregation Girao, Schneider, Westhoff
  Castellucia, Tsudik

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Secure Routing Proposals for MANET

• ARIADNE Hu, et al.
• SRP Papadimitriou, Haas
• security associations between source end
  destination only
• ARAN Dahill, et al.
• PK certificates for IP _at_
• SEAD HU, et al.
• proactive routing - authenticated hash chains
• TESLA with instant key disclosure (TIK)
• can cope with wormhole attack

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Key Management Challenges

• Lack of (or limited)
• Security infrastructure
• Key servers (KDC, CA, RA)
• Organization (a priori trust)
• p2p
• Authentication is not sufficient to build trust
• ? Bootstrapping security associations from
  scratch
• ? Fully distributed
• ? Minimum dependency

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Key Management

• Symmetric
• Key pre-distribution
• Key agreement
• Asymmetric Keys
• PK Certificate (ID,PK)CA
• Self-organized CA
• Web of trust(PGP)
• Certificate-less
• Crypto-based IDs ID h(PK)
• ID-based Crypto PK f(ID)
• Context-awareness
• Distance Bounding Protocols
• Seeing-is-believing

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Key pre-distribution

• Sensor Networks TTP-based
• Eschenauer, Gligor ACM CCS02, H. Chan, A.
  Perrig et al, Oakland03
• Wenliang Du et al, INFOCOM04
• Ad Hoc version no TTP A. Chan, INFOCOM04
• Distributed key setup by randomly choosing key
  rings from a public key space
• Cover-Free Family Algorithm
• Neighbors determine intersection of their key
  rings using homomorphic encryption

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(ID, PK) binding Self-organized CA Zhou,
Haas Kong, et al. Yi, Kravets Lehane, et
al.Bechler et al, INFOCOM04

• Based on threshold cryptography
• PROs distributed, self-organized
• CONs share distribution during bootstrap phase,
  network density, Sybil attack

cert(PKi)SK1
cert(PKi)SK2
PKi
cert(PKi)SKi
Verification of CERT(PKi)SK by any node using
well known PK
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(ID, PK) binding Web of Trust (PGP) Hubaux,
Buttyan, Capkun

• No CA
• Alice ? Bob and Bob ? Eve ? Alice ? Eve
• Merging of certificate repositories
• PROs no centralized TTP
• CONs initialization, storage, transitivity of
  trust

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(ID, PK) binding Crypto-based ID

• SPKI Rivest
• Statistically Unique Cryptographically Verifiable
  IDs OShea, Roe Montenegro, Castellucia
• IPv6 _at_ NW Prefix h(PK)
• DSR using SUCV-based IP addresses
• Bobba, et al
• PROs no certificates, no CA
• CONs generation of bogus IDs

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(ID, PK) binding ID-based CryptoHalili, Katz,
Arbaugh
Based on Boneh, Franklin, CRYPTO 2001

• ID-based
• PK h(ID)
• SK computed by TTP
• Threshold Crypto to distribute TTP
• PROs no certificates, no centralized server
• CONs distribution of initial shares

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Trust

• Managed environment
• A-priori trust
• Authentication ? trustworthiness
• But
• requirement for infrastructure
• scarcity of computing resources (sensors)
• lack of connectivity (sensors, ad hoc nw)
• Open environment
• No a-priori trust
• authentication does not guarantee correct
  operation
• ? New paradigms
• Trust establishment protocols (history, e-cash,
  ) Bussard, Molva, Roudier, PerCom04,
  PerSec04, iTrust04
• Reputation

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Cooperation enforcement

• Token-based Yang,Meng,Lu
• Nuglets Buttyan,Hubaux
• SPRITE Zhong, Chen, Yang
• CONFIDANTBuchegger,Le Boudec
• CORE Michiardi,Molva
• Beta-Reputation Josang,Ismail

Threshold cryptography
Micro-payment
Reputation-based
Built-in with Application
Bittorrent (P2P)
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Summary

• Main research focus
• Bootstrapping from scratch
• New trust paradigms
• Optimization (computation, bandwidth)
• Solutions yet to come . . .
• Interesting applications of cryptography
• Some untruths and non-sense
• ? Room for creativity

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New Challenges

• Opportunistic Communications
• No end-to-end connectivity
• Collapsed system (Applicationnetwork)
• Data eventually reaches destination
• Trust management
• Forwarding of encrypted data
• Network coding and cryptography
• Data aggregation

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•  
• Selected Publications
• "Analysis of Coalition Formation and Cooperation
  Strategies in Mobile Ad hoc Networks in Ad Hoc
  Networks Journal Volume 3, Issue 2 , March
  2005, Pages 193-219
• Pocket Bluff- A Cooperation enforcing scheduled
  pocket switching protocol submitted to Sigcomm
  Hotnets IV, July 2005
• Non cooperative forwarding in ad hoc networks
  Networking 2005, 4th IFIP International
  Conference on Networking, May 2 - 6, 2005,
  Waterloo, Canada - Springer LNCS Vol 3462, 2005 ,
  pp 486-498
• Policy-based Cryptography Financial
  Cryptography 2005, Dominica, February 2005.
• Ad Hoc Network Security Chapter 12 in Mobile Ad
  Hoc Networking, S. Basagni, M. Conti, S.
  Giordano, I. Stojmenovic (Editors) ISBN
  0-471-37313-3 June 2004, Wiley-IEEE Press
• IDHC ID-based Hash-Chains for broadcast
  authentication in wireless networks, EURECOM
  Technical Report RR-04-111
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• History-based Trust Establishment Protocols in
  PerCom04 and iTrust04, March 2004.
• CORE a collaborative reputation mechanism to
  enforce node cooperation in mobile ad hoc
  networks CMS'2002, Communication and Multimedia
  Security 2002 Conference, September 26-27, 2002,
  Portoroz, Slovenia / Also published in the book
  Advanced Communications and Multimedia Security
  /Borka Jerman-Blazic Tomaz Klobucar, editors,
  Kluwer Academic Publishers, ISBN 1-4020-7206-6,
  August 2002 , 320 pp
• "Ad Hoc Network Security" Chapter to appear in
  Handbook of Information Security, H. Bidgoli
  (Editor), Wiley Sons
• Other papers on http//www.eurecom.fr/ce/researchc
  e/nsteam.fr.htm