ahmed osama research assistant. presentation outline winc- nile university- privacy preserving over...
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Privacy Preservation Over Network Coding
Ahmed Osama
Research Assistant
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Presentation Outline
Winc- Nile University- Privacy Preserving Over Network Coding
Introduction Network coding Applications of network coding: recent work
Primitives Linear Network Coding Traffic analysis
Privacy preserving Scheme Security proposed scheme
Future work References
Winc- Nile University- Privacy Preserving Over Network Coding
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Network Coding
Network coding is a field of information theory and coding theory and is a method of attaining maximum information flow in a network [Wikipedia].
Pioneering work: [1] R. Ahlswede, N. Cai, S.-Y. R. Li, and R.W. Yeung, “Network information flow,” IEEE Trans. on Information Theory, vol. 46, no. 4, July 2000.
Winc- Nile University- Privacy Preserving Over Network Coding
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Network CodingExample Simple store and forward Multicast rate of 1.5 bits per time unit
Winc- Nile University- Privacy Preserving Over Network Coding
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Network Coding X-OR is one of the simplest form of data
coding Multicast rate of 2 bits per time unit
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Presentation Outline
Winc- Nile University- Privacy Preserving Over Network Coding
Introduction Network coding Applications of network coding: recent work
Primitives Linear Network Coding Traffic analysis “Unobservability Vs Anonymity”
Privacy preserving Scheme Security proposed scheme
Future work References
Winc- Nile University- Privacy Preserving Over Network Coding
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Applications of network coding: recent work
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Application 1:Content DistributionDistribute content to millions of users, such as Software updates Music Films
Traditional MethodContent collected in servers, clients connect to servers to download the information.Problems:Not-scalable, expensive, slow and Single point of failure
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Application 1:Content Distribution P2P networks:
Capacity and computational power of thenetwork increases with the number of users
Avalanche
Example
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Application 2:Vehicular Networks Vehicles communicate with each other and
with roadside infrastructure to increase safety and optimize traffic.
[Y. Lin ;MobiOpp 2007]
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Presentation Outline
Winc- Nile University- Privacy Preserving Over Network Coding
Introduction Network coding Applications of network coding: recent work
Primitives Linear Network Coding Traffic analysis
Privacy preserving Scheme Security proposed scheme
Future work References
Winc- Nile University- Privacy Preserving Over Network Coding
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Linear Network Coding
The output flow at a given node is obtained as a linear combination of its input flows. The coefficients of the combination are, by definition, selected from a finite field
……
x1
x2
xn
n
iiixay
Paper Summary- WINC- Nile University
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Network Model
t
s
t
s ϵ V
T ϵ V ; t means one destinationAcyclic graph Is the multi
cast capacity and x1…..,xh
Edge symbols comes from a finite field Fq
y(e) is the symbol carried
on edge e
ᵝ(e) is the LEV
),( TsMinCuth
'
' )'()()(e
e eyeey
Paper Summary- WINC- Nile University
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Network Model
T ϵ V ; t means one destination
Acyclic graph By induction we can
calculate that
Global Encoding
Vector(GEV) g(e) = [g1(e),
….gh(e)]
h
iie xegey
1' )()(
'
' )'()()(e
e egeeg
t
s
t
s ϵ V
Paper Summary- WINC- Nile University
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Network Model
By induction we can
calculate that
Global Encoding
Vector(GEV) g(e) = [g1(e),
….gh(e)]
h
iie xegey
1' )()(
'
' )'()()(e
e egeeg
h
t
hhhh
h
h x
x
G
x
x
egeg
egeg
ey
ey
.
.
.
.
.
.
)(...)(
...
...
...
)(...)(
)(.
.
.)( 11
1
1111
Global Encoding Matrix
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Presentation Outline
Winc- Nile University- Privacy Preserving Over Network Coding
Introduction Network coding Applications of network coding: recent work
Primitives Linear Network Coding Traffic analysis
Privacy preserving Scheme Security proposed scheme
Future work References
Winc- Nile University- Privacy Preserving Over Network Coding
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Traffic analysis
Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication. It can be performed even when the messages are encrypted and cannot be decrypted. In general, the greater the number of messages observed, or even intercepted and stored, the more can be inferred from the traffic.
Passive attack
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Presentation Outline
Winc- Nile University- Privacy Preserving Over Network Coding
Introduction Network coding Applications of network coding: recent work
Primitives Linear Network Coding Traffic analysis
Privacy preserving Scheme Security proposed scheme
Future work References
Winc- Nile University- Privacy Preserving Over Network Coding
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Security proposed schemeProblem Statement Privacy threats exist in network coding since
explicit GEVs provide a back door for adversaries.
We need to prevent flow tracing to protect source and destination from being revealed, Specially in multi-hop wireless network.
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Security proposed scheme Solution
Encoding Global Encoding Vectors using Homomorphic Functions
Homomorphism means operations on plain text can be performed by operating on corresponding cipher text. We need additive propertyE(x+y) = Add(E(x),E(y)) Also we need Scalar Multiplicative propertyE(t.x) = Mul(E(x),t)
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Presentation Outline
Winc- Nile University- Privacy Preserving Over Network Coding
Introduction Network coding Applications of network coding: recent work
Primitives Linear Network Coding Traffic analysis
Privacy preserving Scheme Security proposed scheme
Future work References
Winc- Nile University- Privacy Preserving Over Network Coding
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Future Work Propose a scheme that provide less
computational overhead. Authentication vs. privacy tradeoff
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References [1] Y. Lin, B. Liang, and B. Li, “Performance Modeling of
Network Coding in Epidemic Routing,” in Proc. of the First ACM International Workshop on Mobile Opportunistic Networking (MobiOpp), 2007.
[2] S.-Y. R. Li, R. W. Yeung, and N. Cai, “Linear network Coding”, IEEE Trans. on Information Theory, vol. 49, no. 2, Feb. 2003.
[3] R. Ahlswede, N. Cai, S.-Y. R. Li, and R.W. Yeung, “Network information flow,” IEEE Trans. on Information Theory, vol. 46, no. 4, July 2000.
[4] Y. Fan, Y. Jiang, H. Zhu, and X. Shen, "An Efficient Privacy-Preserving Scheme against Traffic Analysis Attacks in Network Coding", Proc.IEEE INFOCOM'09, Rio de Janeiro, Brazil, April 19-25, 2009.
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Thank you
Any Questions ?